阅读说明：本技术 搭载于超重力离心机的定向凝固熔铸系统 (Directional solidification casting system carried on hypergravity centrifugal machine ) 是由 韦华 谢亚丹 王江伟 林伟岸 张泽 陈云敏 于 2019-09-10 设计创作，主要内容包括：本发明公开了一种搭载于超重力离心机的定向凝固熔铸系统。定向凝固熔铸系统包括高温加热子系统和坩埚及气冷系统,高温加热子系统固定于超重力试验舱中,坩埚及气冷系统置于高温加热子系统中；高温加热子系统包括上中下炉体以及莫来石保温层、上下加热腔外体、上下加热炉管、坩埚支撑座和发热体,高温加热腔体分为上下部分,内部加工有螺旋状凹槽并装有发热体；坩埚支撑座内部有冷却气体通入的通气管道；坩埚及气冷系统包括进气管、冷却底座、冷速调节环、坩埚、排气盖和排气管。本发明配合超重力环境,解决了高速旋转状态下定向凝固熔铸温度梯度的关键难题,填补了国内技术行业的空白,且装备简单、操作方便。(The invention discloses a directional solidification casting system carried on a hypergravity centrifugal machine. The directional solidification casting system comprises a high-temperature heating subsystem, a crucible and an air cooling system, wherein the high-temperature heating subsystem is fixed in the supergravity test chamber, and the crucible and the air cooling system are arranged in the high-temperature heating subsystem; the high-temperature heating subsystem comprises an upper furnace body, a middle furnace body, a lower furnace body, a mullite heat-insulating layer, an upper heating cavity body, a lower heating cavity body, an upper heating furnace tube, a lower heating furnace tube, a crucible supporting seat and a heating element, wherein the high-temperature heating cavity body is divided into an upper part and a lower part, and a spiral groove is processed in the high-temperature heating; a ventilation pipeline for introducing cooling gas is arranged in the crucible supporting seat; the crucible and air cooling system comprises an air inlet pipe, a cooling base, a cooling speed adjusting ring, a crucible, an exhaust cover and an exhaust pipe. The invention solves the key problem of directional solidification casting temperature gradient in a high-speed rotation state by matching with a supergravity environment, fills the blank of the domestic technical industry, and has simple equipment and convenient operation.)

1. A directional solidification casting system carried on a hypergravity centrifuge is characterized in that: the directional solidification casting system comprises a high-temperature heating subsystem, a crucible and an air cooling system, wherein the high-temperature heating subsystem is fixed in the supergravity test chamber, and the crucible and the air cooling system are arranged in the high-temperature heating subsystem;

the high-temperature heating subsystem comprises a mounting base (23), and an upper furnace body, a middle furnace body, a lower furnace body, a mullite heat-insulating layer (16), an upper heating cavity outer body (17), a lower heating cavity outer body (18), an upper heating furnace tube (19), a lower heating furnace tube (20), a crucible supporting seat (21) and a heating body (22) which are arranged on the mounting base (23) and connected in sequence from top to bottom; the upper furnace body mainly comprises an upper heat insulation cover (1), an upper furnace body shell (2), an upper furnace body middle shell (3), an upper furnace body heat insulation layer (4) and an upper furnace body lower fixing cover (5), wherein the upper furnace body shell (2), the upper furnace body middle shell (3) and the upper furnace body heat insulation layer (4) are respectively installed from outside to inside to form an upper furnace three-layer structure, the upper heat insulation cover (1) and the upper furnace body lower fixing cover (5) are respectively installed at the upper end and the lower end of the upper furnace three-layer structure to enable the upper furnace three-layer structure to be fixedly connected, and gaps are respectively reserved between the upper furnace body shell (2) and the upper furnace body middle shell (3) and between the upper furnace body middle shell (3) and the upper furnace body heat; the middle furnace body mainly comprises a middle cavity heat cover (6), a middle cavity outer shell (7), a middle cavity middle shell (8), a middle cavity heat-insulating layer (9) and a middle cavity lower fixing cover (10), wherein the middle cavity outer shell (7), the middle cavity middle shell (8) and the middle cavity heat-insulating layer (9) are respectively installed from outside to inside to form a middle furnace three-layer structure, the middle cavity heat cover (6) and the middle cavity lower fixing cover (10) are respectively installed at the upper end and the lower end of the middle furnace three-layer structure to fixedly connect the middle furnace three-layer structure, and gaps are respectively reserved between the middle cavity outer shell (7) and the middle cavity middle shell (8) and between the middle cavity middle shell (8) and the middle cavity heat-insulating layer (9) to serve as air heat-insulating layers; the upper cavity lower fixed cover (5) of the upper furnace body is fixedly connected with the middle heat insulation cover (6) of the middle furnace body; the lower furnace body mainly comprises a lower heat insulation cover (11), a lower cavity outer shell (12), a lower cavity middle shell (13), a lower cavity heat insulation layer (14) and a lower cavity lower fixing cover (15), the lower cavity outer shell (12), the lower cavity middle shell (13) and the lower cavity heat insulation layer (14) are respectively installed from outside to inside to form a lower furnace three-layer structure, the lower heat insulation cover (11) and the lower cavity lower fixing cover (15) are respectively installed at the upper end and the lower end of the lower furnace three-layer structure to enable the lower furnace three-layer structure to be fixedly connected, the bottom of the lower cavity lower fixing cover (15) is fixed on the installation base (23) through bolts and screws, the installation base (23) is fixed on a hypergravity experiment cabin base of the hypergravity centrifuge, gaps are respectively reserved between the lower cavity outer shell (12) and the lower cavity middle shell (13) and between the lower cavity middle shell (13) and the lower cavity heat insulation layer (14) to serve as air heat insulation layers; the lower fixed cover (10) of the middle cavity of the middle furnace body is fixedly connected with the lower heat insulation cover (11) of the lower furnace body;

the crucible supporting seat (21) is arranged at the bottom of a lower cavity heat insulation layer (14) of the lower furnace body, the bottom of the crucible supporting seat is fixed on an installation base (23), the heating cavity is arranged on the crucible supporting seat (21), the heating cavity comprises an upper heating cavity outer body (17), a lower heating cavity outer body (18), an upper heating furnace tube (19) and a lower heating furnace tube (20), the upper heating cavity outer body (17) and the lower heating cavity outer body (18) are of sleeve structures, the upper heating cavity outer body (17) and the lower heating cavity outer body (18) are respectively positioned in upper and lower coaxial fixed butt joint, the upper heating furnace tube (19) and the lower heating furnace tube (20) are respectively sleeved in the upper heating cavity outer body (17) and the lower heating cavity outer body (18, a mullite heat-insulating layer (16) is filled among an upper heating cavity outer body (17), a lower heating cavity outer body (18), an upper cavity heat-insulating layer (4) of the upper furnace body, a middle cavity heat-insulating layer (9) of the middle furnace body and a lower cavity heat-insulating layer (14) of the lower furnace body; spiral grooves (22-1) are processed on the outer walls of the upper heating furnace tube (19) and the lower heating furnace tube (20), spiral heating bodies (22) are arranged in the spiral grooves (22-1), heat generated by the heating bodies (22) is uniformly radiated to the heating furnace tube consisting of the upper heating furnace tube (19) and the lower heating furnace tube (20), and a high-temperature region is formed in the center of the heating furnace tube.

2. The directional solidification casting system mounted on a hypergravity centrifuge as claimed in claim 1, wherein: the heating body (22) generates heat in the working process, the upper heating furnace tube (19) and the lower heating furnace tube (20) are heated through radiation, a high-temperature area is formed in the center of the heating furnace tube, the pitch of the spiral grooves (22-1) at different height positions is changed, the distance between the heating furnace tubes and the heating body (22) at different height positions is further changed, the temperature and the flow of cooling gas introduced through the ventilation pipeline (21-1) of the crucible supporting seat (21) are matched, cooling is started from the bottom of the crucible, and a temperature gradient along the supergravity direction is formed.

3. The directional solidification casting system mounted on a hypergravity centrifuge as claimed in claim 1, wherein: the upper heating furnace tube (19) and the lower heating furnace tube (20) are made of ceramics with high strength and low heat conductivity coefficient.

4. The directional solidification casting system mounted on a hypergravity centrifuge as claimed in claim 1, wherein: the experimental cabin is also internally provided with a bearing frame, a signal collector and a wiring frame, material samples to be directionally solidified are arranged in an upper heating furnace tube (19) and a lower heating furnace tube (20) of the high-temperature heating subsystem, the upper heating furnace tube and the lower heating furnace tube are also provided with temperature sensors, the temperature sensors are connected with the signal collector, and a lead output by the signal collector is connected with a weak signal conductive slip ring through the wiring frame and then is connected with a ground measurement and control center;

the high-temperature heating subsystem is provided with a strong current independent loop, the strong current independent loop controls heating bodies (22) at different height positions in the high-temperature heating system to carry out high-temperature heating, and a strong current independent loop on the ground is connected into a wiring frame of the hypergravity experiment cabin through a centrifugal centrifuge main shaft conductive slip ring;

the high-temperature heating subsystem is provided with a cooling gas loop, the cooling gas independent loop controls the flow of introduced cooling gas, and a cooling gas independent loop on the ground is connected into a cooling gas pipeline support and an exhaust pipe of the hypergravity experiment chamber through a centrifugal centrifuge main shaft conductive slip ring.

5. The directional solidification casting system mounted on a hypergravity centrifuge as claimed in claim 1, wherein: the crucible and air cooling system is arranged in an upper heating furnace tube (19) and a lower heating furnace tube (20) on a crucible supporting seat (21), and comprises an air inlet pipe (29), a cooling base (26), a cooling speed adjusting ring (27), a crucible (25), an exhaust cover (28) and an exhaust pipe (30); a cooling base (26) is arranged on the top surface of the crucible supporting seat (21), a crucible (25) is arranged on the cooling base (26), an exhaust cover (28) is arranged at the top end of the crucible (25), and a cooling speed adjusting ring (27) is sleeved in the middle of the crucible (25); a central cavity (25-1), a cooling hole (25-2), a temperature gradient adjusting block (25-3), a heat radiation groove (25-4), a positioning flange block (25-5), a heat dissipation groove (25-6) and a gas discharge hole (25-7) are arranged on the crucible (25); the crucible (25) main body is of a cylindrical structure, a cylindrical blind hole is formed in the center of the top surface of the crucible (25) and serves as a central containing cavity (25-1), and molten metal/metal samples to be subjected to supergravity directional solidification are filled in the central containing cavity (25-1); a plurality of vertical through holes are formed in the top surface of the crucible (25) around the central cavity (25-1) along the circumference to serve as cooling holes (25-2), the plurality of cooling holes (25-2) are uniformly distributed at intervals along the circumferential direction, and cooling gas is introduced into the lower ends of the cooling holes (25-2); a temperature gradient adjusting block (4) for realizing and adjusting the directional solidification temperature gradient is arranged in each cooling hole (25-2), a gap exists between the temperature gradient adjusting block (4) and the hole wall of the cooling hole (25-2), and the temperature gradient adjusting block (4) can move up and down in the axial direction of the cooling hole (25-2); an annular bump is fixed on the circumferential surface of the lower part of the crucible (25) and serves as a positioning flange block (25-5), a plurality of heat dissipation grooves (25-6) are formed in the peripheral cylindrical surface of the lower part of the positioning flange block (25-5), and the heat dissipation grooves (25-6) radially extend outwards from the inner wall of the crucible (25) main body to form the outer wall of the positioning flange block (25-5); a plurality of heat radiation grooves (25-4) are formed in the peripheral cylindrical surface of the crucible (25) above the positioning flange block (25-5), the plurality of heat radiation grooves (25-4) are uniformly distributed at intervals along the circumferential direction, and one heat radiation groove (25-4) is formed in the peripheral cylindrical surface of the crucible (25) between every two adjacent cooling holes (25-2); through holes are symmetrically formed in the two sides of the side wall of the crucible (25) at the top surface of the positioning flange block (25-5) and serve as gas discharge holes (25-7), and the gas discharge holes (25-7) are used for communicating the cooling holes (25-3) with the outside of the crucible (25); an air duct (21-1) is arranged in the crucible supporting seat (21), the lower end of the air duct (21-1) penetrates out of the outer wall of the bottom of the crucible supporting seat (21) and is connected with one end of an air inlet pipe (29), and the other end of the air inlet pipe (29) is connected with a cooling air source; the upper end of a cooling base (26) is opened, a lower annular groove (26-2) is arranged in the opening, the lower end of a crucible (25) is arranged in the opening at the upper end of the cooling base (26), the lower ends of cooling holes (25-2) of the crucible (25) are communicated through the lower annular groove (26-2), an air inlet through hole (26-1) communicated with the lower annular groove (26-2) is formed in the bottom end of the cooling base (26), and the upper end of an air duct (21-1) of a crucible supporting seat (21) penetrates through the top surface of the crucible supporting seat (21) and is communicated with the air inlet through hole (26-1) of the cooling base (26); the cooling speed adjusting ring (27) is fixedly arranged on a positioning flange block (25-5) of the crucible (25), one or two vertical gas collecting slotted holes (27-1) are formed in the top surface of the cooling speed adjusting ring (27), and the bottom ends of the gas collecting slotted holes (27-1) penetrate through the inner ring wall surface of the cooling speed adjusting ring (27) and are communicated with gas discharge holes (25-7) of the crucible (25); the lower end of the exhaust cover (28) is opened, an upper annular groove (28-2) is arranged in the opening, the lower end of the crucible (25) is arranged in the opening at the lower end of the exhaust cover (28), the upper ends of the cooling holes (25-2) of the crucible (25) are communicated through the upper annular groove (28-2), the bottom end of the exhaust cover (28) is provided with an air outlet through hole (28-1) communicated with the upper annular groove (28-2), and the air outlet through hole (28-1) of the exhaust cover (28) is communicated with one end of an exhaust pipe (30); the other end of the exhaust pipe (30) is communicated with the outside to exhaust the cooling gas;

an air duct (21-1) is arranged in the crucible supporting seat (21), the air duct (21-1) is used for introducing cooling gas for directional solidification, the upper end of the air duct (21-1) penetrates through the top surface of the crucible supporting seat (21) to serve as an outlet and is communicated with the interior of the lower heating furnace tube (20), and the lower end of the air duct (21-1) penetrates through the bottommost part of the crucible supporting seat (21) to serve as an inlet; cooling gas for the directional solidification test enters through an inlet at the lower end of the vent pipe (21-1), enters the bottom of the crucible (25) through an outlet at the upper end of the vent pipe (21-1), forms a temperature gradient along the direction of supergravity for directional solidification by cooling the bottom of the crucible (25), and regulates the temperature gradient distribution along the direction of supergravity by regulating the introduction flow of the cooling gas and the temperature generated by the heating body (22).

6. The directional solidification casting system mounted on a hypergravity centrifuge as set forth in claim 5, wherein: the crucible (25) is used for containing molten metal/metal samples in the directional solidification process under the super-gravity environment.

7. The directional solidification casting system mounted on a hypergravity centrifuge as set forth in claim 5, wherein: the cooling gas is liquid nitrogen, compressed air or the like, the temperature of the cooling gas is not higher than 5 ℃, and the pressure of the cooling gas is not higher than 5 Mpa.

8. The directional solidification casting system mounted on a hypergravity centrifuge as claimed in claim 1, wherein: the directional solidification casting system is arranged in a hypergravity environment of a centrifugal machine.

Technical Field

The invention relates to the field of high-temperature heating, in particular to a directional solidification casting system carried on a hypergravity centrifugal machine.

Background

The high-pressure turbine working blade is one of key components of a hot end part of an aeroengine and a gas turbine, works under coupling loading conditions of high temperature, high pressure, high rotating speed, alternating load and the like for a long time in service, is a rotating part with the worst working condition in the engine, and the use reliability of the rotating part directly influences the performance of the whole engine. In the development process of the high-temperature alloy, the process plays a great promoting role in the development of the high-temperature alloy. Generally, in order to improve the comprehensive mechanical property of the high-temperature alloy, two approaches are adopted: one is that a large amount of alloying elements are added, and solid solution strengthening, precipitation strengthening, grain boundary strengthening and the like are generated through a reasonable heat treatment process, so that the high-temperature alloy is ensured to have good strength from room temperature to high temperature, surface stability and better plasticity; and secondly, starting from a solidification process, preparing columnar crystal high-temperature alloy with grain boundaries parallel to a main stress axis so as to eliminate harmful transverse grain boundaries or preparing single crystal high-temperature alloy with all grain boundaries eliminated by adopting a directional solidification process.

Because the transverse crystal boundary of the directional and single crystal blade is eliminated or the crystal boundary is completely eliminated, the crystal grows along the specific direction of [001], the initial melting temperature and the temperature of a solid solution treatment window are improved, the number of gamma rays is increased and refined, the performance is greatly improved, and the use temperature is improved. At present, almost all advanced aircraft engines use single crystal superalloys. The single crystal alloy prepared by the rapid solidification method widely applied to industry has the temperature gradient of only about 100K/cm, and the solidification rate is very low, so that the solidification structure is thick, the segregation is serious, and the performance of the material is not fully exerted. The crystal growth under microgravity effectively inhibits the irregular thermal mass convection caused by gravity due to the reduction of the acceleration of gravity, thereby obtaining the crystal with highly uniform solute distribution, but the cost is too high to be industrialized.

The single crystal alloy can be prepared in a hypergravity environment, but the prior art lacks a temperature gradient control system for realizing directional solidification in the hypergravity environment and lacks a system for realizing directional solidification casting in the hypergravity environment.

Disclosure of Invention

The invention aims to solve the problem that a sample is difficult to heat in the process of directionally solidifying and casting a material under the conditions of supergravity and high temperature test, and provides a directional temperature gradient solidifying system which is simple in assembly, convenient to use, high in safety coefficient and capable of being used in the supergravity working condition, and the preparation of a single crystal alloy under the supergravity is possible.

The technical scheme adopted by the invention is as follows:

the directional solidification casting system comprises a high-temperature heating subsystem, a crucible and an air cooling system, wherein the high-temperature heating subsystem is fixed in a supergravity test chamber, and the crucible and the air cooling system are arranged in the high-temperature heating subsystem.

The high-temperature heating subsystem comprises a mounting base, and an upper furnace body, a middle furnace body, a lower furnace body, a mullite heat-insulating layer, an upper heating cavity outer body, a lower heating cavity outer body, an upper heating furnace tube, a lower heating furnace tube, a crucible supporting seat and a heating body which are sequentially arranged and connected from top to bottom on the mounting base; the upper furnace body mainly comprises an upper heat insulation cover, an upper cavity shell, an upper cavity middle shell, an upper cavity heat insulation layer and an upper cavity lower fixing cover, wherein the upper cavity shell, the upper cavity middle shell and the upper cavity heat insulation layer are respectively installed from outside to inside to form an upper furnace three-layer structure; the middle furnace body mainly comprises a middle heat insulation cover, a middle cavity shell, a middle cavity middle shell, a middle cavity heat insulation layer and a middle cavity lower fixing cover, wherein the middle cavity shell, the middle cavity middle shell and the middle cavity heat insulation layer are respectively installed from outside to inside to form a middle furnace three-layer structure; the upper cavity lower fixing cover of the upper furnace body is fixedly connected with the middle heat insulation cover of the middle furnace body; the lower furnace body mainly comprises a lower heat insulation cover, a lower cavity shell, a lower cavity middle shell, a lower cavity heat insulation layer and a lower cavity lower fixing cover, wherein the lower cavity shell, the lower cavity middle shell and the lower cavity heat insulation layer are respectively installed from outside to inside to form a lower furnace three-layer structure; the lower fixed cover of the middle cavity of the middle furnace body is fixedly connected with the lower heat insulation cover of the lower furnace body.

The crucible supporting seat is arranged at the bottom of a lower cavity heat insulation layer of the lower furnace body, the bottom of the crucible supporting seat is fixed on the mounting base, the heating cavity is arranged on the crucible supporting seat and comprises an upper heating cavity outer body, a lower heating cavity outer body, an upper heating furnace tube and a lower heating furnace tube, the upper heating cavity outer body and the lower heating cavity outer body are of sleeve structures, the upper heating cavity outer body and the lower heating cavity outer body are respectively positioned in upper and lower coaxial fixed butt joint, the upper heating furnace tube and the lower heating furnace tube are respectively sleeved in the upper heating cavity outer body and the lower heating cavity outer body, and mullite heat insulation layers are filled between an upper cavity heat insulation layer of the upper furnace body, a middle cavity heat insulation layer of the middle furnace body and a lower cavity heat insulation layer of the lower furnace body; the outer walls of the upper heating furnace tube and the lower heating furnace tube are both processed with spiral grooves, spiral heating bodies are arranged in the spiral grooves, heat generated by the heating bodies is uniformly radiated to the heating furnace tube consisting of the upper heating furnace tube and the lower heating furnace tube, and a high-temperature area is formed in the center of the heating furnace tube.

The heating element produces heat in the working process, through radiation heating upper heating furnace tube and lower heating furnace tube, forms the high temperature region at heating furnace tube central authorities, and the heliciform recess pitch through changing different height position and then change the heating element of different height position at heating furnace tube interval, and the cooling gas temperature and the flow that cooperation crucible supporting seat breather line lets in begin to cool off from the crucible bottom, form a temperature gradient along the hypergravity direction.

The upper heating furnace tube and the lower heating furnace tube are made of ceramics with high strength and low heat conductivity coefficient.

The experimental cabin is also internally provided with a bearing frame, a signal collector and a wiring frame, material samples to be directionally solidified are arranged in an upper heating furnace tube and a lower heating furnace tube of the high-temperature heating subsystem, and are provided with temperature sensors, the temperature sensors are connected with the signal collector, and a lead output by the signal collector is connected with a weak signal conductive slip ring through the wiring frame and then is connected with a ground measurement and control center; the high-temperature heating subsystem is provided with a strong electric independent loop, the strong electric independent loop controls and heats heating bodies at different height positions in the high-temperature heating subsystem to carry out high-temperature heating, and a strong electric independent loop on the ground is connected into a wiring frame of the hypergravity experimental cabin through a centrifugal centrifuge main shaft conductive slip ring; the high-temperature heating subsystem is provided with a cooling gas loop all the way, the flow of the introduced cooling gas is controlled by a cooling gas independent loop all the way, and a cooling gas independent loop on the ground is connected into a cooling gas pipeline support and an exhaust pipe of the hypergravity experiment cabin through a centrifugal centrifuge main shaft conductive slip ring.

The crucible and air cooling system is arranged in the upper heating furnace tube and the lower heating furnace tube on the crucible supporting seat, and comprises an air inlet pipe, a cooling base, a cooling speed adjusting ring, a crucible, an exhaust cover and an exhaust pipe; a cooling base is arranged on the top surface of the crucible supporting seat, a crucible is arranged on the cooling base, an exhaust cover is arranged at the top end of the crucible, and a cooling speed adjusting ring is sleeved in the middle of the crucible; the crucible is provided with a central cavity, a cooling hole, a temperature gradient adjusting block, a heat radiation groove, a positioning flange block, a heat dissipation groove and a gas discharge hole; the crucible main body is of a cylindrical structure, a cylindrical blind hole is formed in the center of the top surface of the crucible and serves as a central containing cavity, and molten metal/metal samples to be directionally solidified by supergravity are filled in the central containing cavity; a plurality of vertical through holes serving as cooling holes are formed in the top surface of the crucible around the central cavity along the circumference, the plurality of cooling holes are uniformly distributed at intervals along the circumferential direction, and cooling gas is introduced into the lower ends of the cooling holes; a temperature gradient adjusting block for realizing and adjusting the directional solidification temperature gradient is arranged in each cooling hole, a gap exists between the temperature gradient adjusting block and the wall of the cooling hole, and the temperature gradient adjusting block can move up and down along the axis in the cooling hole; an annular bump is fixed on the circumferential surface of the lower part of the crucible and serves as a positioning flange block, a plurality of radiating grooves are formed in the peripheral cylindrical surface of the lower part of the positioning flange block, and the radiating grooves radially extend outwards from the inner wall of the crucible main body to form the outer wall of the positioning flange block; a plurality of heat radiation grooves are formed in the peripheral cylindrical surface of the crucible above the positioning flange block and are uniformly distributed at intervals along the circumferential direction, and one heat radiation groove is formed in the peripheral cylindrical surface of the crucible between every two adjacent cooling holes; through holes are symmetrically formed in the two sides of the side wall of the crucible at the top surface of the positioning flange block and serve as gas discharge holes, and the cooling holes are communicated with the outside of the crucible through the gas discharge holes; an air duct is arranged in the crucible supporting seat, the lower end of the air duct penetrates out of the outer wall of the bottom of the crucible supporting seat and is connected with one end of an air inlet pipe, and the other end of the air inlet pipe is connected with a cooling air source; the upper end of the cooling base is opened, a lower annular groove is arranged in the opening, the lower end of the crucible is arranged in the opening at the upper end of the cooling base, the lower ends of the cooling holes of the crucible are communicated through the lower annular groove, the bottom end of the cooling base is provided with an air inlet through hole communicated with the lower annular groove, and the upper end of an air duct of the crucible supporting seat penetrates out of the top surface of the crucible supporting seat and is communicated with the air inlet through hole of the cooling base; the cold speed adjusting ring is fixedly arranged on a positioning flange block of the crucible, one or two vertical gas collecting slotted holes are formed in the top surface of the cold speed adjusting ring, and the bottom ends of the gas collecting slotted holes penetrate through the wall surface of the inner ring of the cold speed adjusting ring and are communicated with gas discharge holes of the crucible; the lower end of the exhaust cover is provided with an opening, an upper annular groove is arranged in the opening, the lower end of the crucible is arranged in the opening at the lower end of the exhaust cover, the upper ends of the cooling holes of the crucible are communicated through the upper annular groove, the bottom end of the exhaust cover is provided with an air outlet through hole communicated with the upper annular groove, and the air outlet through hole of the exhaust cover is communicated with one end of an exhaust pipe; the other end of the exhaust pipe is communicated with the outside to discharge the cooling gas.

The crucible supporting seat is internally provided with an air duct for introducing cooling gas for directional solidification, the upper end of the air duct penetrates out of the top surface of the crucible supporting seat to serve as an outlet and is communicated with the inner part of the lower heating furnace tube, and the lower end of the air duct penetrates out of the bottommost part of the crucible supporting seat to serve as an inlet; the cooling gas of directional solidification test gets into through the inlet of breather pipe lower extreme, lets in the crucible bottom through the export of breather pipe upper end, through cooling to the crucible bottom, forms one along the temperature gradient of hypergravity direction and carries out directional solidification to through the temperature that the flow and the heat-generating body produced that let in of regulation and control cooling gas, the temperature gradient distribution along the hypergravity direction is regulated and controlled.

The crucible is used for containing molten metal/metal samples in the directional solidification process under the super-gravity environment.

The cooling gas is liquid nitrogen, compressed air or the like, the temperature of the cooling gas is not higher than 5 ℃, and the pressure of the cooling gas is not higher than 5 Mpa.

The directional solidification casting system is arranged in a hypergravity environment of a centrifugal machine.

The invention realizes a temperature gradient control system for realizing directional solidification under a supergravity environment, so that crystal growth can be carried out under supergravity, buoyancy convection is enhanced by increasing the acceleration of gravity, when the buoyancy convection is enhanced to a certain degree, the buoyancy convection is converted into a laminar state, namely, laminar flow is carried out again, and irregular heat mass flow is also inhibited. Forced convection of the liquid phase is caused during the accelerated rotation, which causes significant changes in the interface morphology due to greatly changing heat and mass transport processes, resulting in a significant reduction in the width of the mushy zone. The liquid phase fast flow causes the temperature gradient in the liquid phase at the front edge of the interface to be greatly improved, which is very beneficial to the uniform mixing of liquid phase solutes and the planar interface growth of materials, the growth form of dendritic crystals is obviously changed from the original dendritic crystals with obvious main axes to spike crystals without the obvious main axes, and the spike crystals have fine microstructures.

The invention has the beneficial effects that:

the invention provides a set of directional solidification device and a method for the directional solidification device under the hypergravity environment, which can perform a temperature gradient control treatment process on a material sample needing directional solidification casting under the hypergravity environment, can realize the directional solidification casting of the material under the centrifugal load-thermal load coupling condition, can effectively solve the problem of the temperature gradient of the directional solidification casting of the material under the hypergravity and high-temperature test conditions, and has the advantages of simple structure, operation scheme and higher safety factor.

The invention is matched with a supergravity environment, can heat a material directional solidification casting sample under the condition of high rotating speed, such as the directional of high-temperature alloy and the growth of single crystal, solves the key problem of material directional solidification casting temperature gradient under the high-speed rotating state, fills the blank of the domestic technical industry, and has simple equipment and convenient operation. The invention is suitable for the super-gravity environment of 1g-2000g, and the heating temperature is from normal temperature to 1250 ℃.

Drawings

FIG. 1 is a front view of a directional solidification melt casting system;

FIG. 2 is a front view of the high temperature heating subsystem;

FIG. 3 is a sectional view of the crucible support base;

FIG. 4 is a partial enlarged view of the heating furnace tube;

FIG. 5 is a schematic view of a heat-generating body;

fig. 6 is a schematic diagram of an electrical connection structure of the directional solidification casting system.

FIG. 7 is a general view of a crucible and air cooling system;

FIG. 8 is a front cross-sectional view of the crucible;

FIG. 9 is an enlarged partial cross-sectional view taken at the location labeled A in FIG. 8;

FIG. 10 is a top view of the crucible;

FIG. 11 is a cross-sectional view A-A of FIG. 8;

FIG. 12 is a perspective view of a crucible.

FIG. 13 is a cross-sectional view of the cooling base;

FIG. 14 is a cross-sectional view of the cold speed adjustment ring;

fig. 15 is a sectional view of the exhaust cover.

FIG. 16 is a schematic view of a directional solidification fusion casting structure in which a crucible and a cooling system are independently installed according to the present invention.

In the figure: the device comprises an upper heat insulation cover 1, an upper cavity shell 2, an upper cavity middle shell 3, an upper cavity heat insulation layer 4, an upper cavity lower fixing cover 5, a middle heat insulation cover 6, a middle cavity shell 7, a middle cavity middle shell 8, a middle cavity heat insulation layer 9, a middle cavity lower fixing cover 10, a lower heat insulation cover 11, a lower cavity shell 12, a lower cavity middle shell 13, a lower cavity heat insulation layer 14, a lower cavity lower fixing cover 15, a mullite heat insulation layer 16, an upper heating cavity outer body 17, a lower heating cavity outer body 18, an upper heating furnace tube 21, a lower heating furnace tube 20, a crucible supporting seat 21, a heating body 22, a spiral groove 21-1, a ventilation pipeline 21-1 and an installation base 23; the device comprises a crucible 25, a central cavity 25-1, a cooling hole 25-2, a temperature gradient adjusting block 25-3, a heat radiation groove 25-4, a positioning flange block 25-5, a heat dissipation groove 25-6 and a gas discharge hole 25-7; an air inlet pipe 29, a crucible supporting seat 21, a cooling base 26, a cooling speed adjusting ring 27, a crucible 25, an exhaust cover 28 and an exhaust pipe 30; the air duct 21-1, the air inlet through hole 26-1, the lower annular groove 26-2, the air collecting groove hole 27-1, the air outlet through hole 28-1, the upper annular groove 28-2 and the boss 28-3.

Detailed Description

The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic views, and merely illustrate the basic structure of the present invention in a schematic manner, and therefore, only show the components related to the present invention.

As shown in fig. 1, the directional solidification fusion casting system includes a high temperature heating subsystem, a crucible and an air cooling system, the high temperature heating subsystem is fixed in the supergravity test chamber, and the crucible and the air cooling system are disposed in the high temperature heating subsystem.

As shown in fig. 2, the high-temperature heating subsystem comprises a mounting base 23, and an upper furnace body, a middle furnace body, a lower furnace body, a mullite heat-insulating layer 16, an upper heating cavity outer body 17, a lower heating cavity outer body 18, an upper heating furnace tube 19, a lower heating furnace tube 20, a crucible supporting seat 21 and a heating element 22 which are arranged on the mounting base 23 and connected in sequence from top to bottom; the upper heat insulation cover 1, the upper cavity shell 2, the upper cavity middle shell 3, the upper cavity heat insulation layer 4, the upper cavity lower fixing cover 5, the middle heat insulation cover 6, the middle cavity shell 7, the middle cavity middle shell 8, the middle cavity heat insulation layer 9, the middle cavity lower fixing cover 10, the lower heat insulation cover 11, the lower cavity shell 12, the lower cavity middle shell 13, the lower cavity heat insulation layer 14 and the lower cavity lower fixing cover 15 form a shell of a cylindrical high-temperature heating subsystem consisting of three furnace bodies.

The upper furnace body mainly comprises an upper heat insulation cover 1, an upper furnace body shell 2, an upper furnace body middle shell 3, an upper furnace body heat insulation layer 4 and an upper furnace body lower fixing cover 5, wherein the upper furnace body shell 2, the upper furnace body middle shell 3 and the upper furnace body heat insulation layer 4 are respectively installed from outside to inside to form an upper furnace three-layer structure, the upper heat insulation cover 1 and the upper furnace body lower fixing cover 5 are respectively installed at the upper end and the lower end of the upper furnace three-layer structure to enable the upper furnace three-layer structure to be fixedly connected, and the upper heat insulation cover 1 is used for fixing the upper furnace three-layer structure of the upper furnace body and plays; gaps are arranged between the upper cavity outer shell 2 and the upper cavity middle shell 3 and between the upper cavity middle shell 3 and the upper cavity heat insulation layer 4 to serve as air heat insulation layers, and the air heat insulation layers play a role in heat insulation and heat preservation to prevent heat in the furnace from being dissipated.

The middle furnace body mainly comprises a middle heat insulation cover 6, a middle cavity outer shell 7, a middle cavity middle shell 8, a middle cavity heat insulation layer 9 and a middle cavity lower fixing cover 10, wherein the middle cavity outer shell 7, the middle cavity middle shell 8 and the middle cavity heat insulation layer 9 are respectively installed from outside to inside to form a middle furnace three-layer structure, the middle heat insulation cover 6 and the middle cavity lower fixing cover 10 are respectively installed at the upper end and the lower end of the middle furnace three-layer structure to enable the middle furnace three-layer structure to be fixedly connected, the middle heat insulation cover 6 is used for fixing the middle furnace three-layer structure of the middle furnace body and plays a role in heat insulation, and the middle heat insulation cover 6 has a heat insulation effect and prevents heat from being conducted downwards under the effect of supergravity; gaps are reserved between the middle cavity outer shell 7 and the middle cavity middle shell 8 and between the middle cavity middle shell 8 and the middle cavity heat-insulating layer 9 to serve as air heat-insulating layers which play a role in heat insulation and heat preservation to prevent heat in the furnace from being dissipated; the upper furnace body lower fixing cover 5 is fixedly connected with the middle heat insulation cover 6 of the middle furnace body, and the upper furnace body lower fixing cover 5 and the middle heat insulation cover 6 are connected to connect the upper furnace body and the middle furnace body.

The lower furnace body mainly comprises a lower heat insulation cover 11, a lower cavity outer shell 12, a lower cavity middle shell 13 and a lower cavity heat insulation layer 14, the lower cavity lower fixing cover 15 is formed, a lower cavity outer shell 12, a lower cavity middle shell 13 and a lower cavity heat insulation layer 14 are respectively installed from outside to inside to form a lower furnace three-layer structure, the lower heat insulation cover 11 and the lower cavity lower fixing cover 15 are respectively installed at the upper end and the lower end of the lower furnace three-layer structure to enable the lower furnace three-layer structure to be fixedly connected, the bottom of the lower cavity lower fixing cover 15 is fixed to an installation base 23 through bolt screws, the installation base 23 is fixed to a hypergravity experiment cabin base of a hypergravity centrifuge, the lower heat insulation cover 11 is used for fixing the lower furnace three-layer structure of the lower furnace body and playing a role in heat insulation, the lower heat insulation cover 11 has a heat insulation role in preventing heat from being conducted downwards under the hypergravity effect, and the lower cavity lower fixing cover 15 is used for fixing a high-temperature heating subsystem at the. Gaps are reserved between the lower cavity outer shell 12 and the lower cavity middle shell 13 and between the lower cavity middle shell 13 and the lower cavity heat insulation layer 14 to serve as air heat insulation layers, and the air heat insulation layers play a role in heat insulation and heat preservation to prevent heat in the furnace from being dissipated; the middle-cavity lower fixed cover 10 of the middle furnace body is fixedly connected with the lower heat insulation cover 11 of the lower furnace body, and the middle-cavity lower fixed cover 10 and the lower heat insulation cover 11 are connected to connect the middle furnace body with the lower furnace body.

The whole furnace body is reinforced through four places, namely an upper heat insulation cover 1, an upper cavity lower fixing cover 5, a middle heat insulation cover 6, a middle cavity lower fixing cover 10, a lower heat insulation cover 11 and a lower cavity lower fixing cover 15, so that the rigidity and the strength of the whole furnace body in a supergravity environment are improved, and the deformation and the damage of the furnace body in the operation process are prevented. The upper cavity lower fixing cover 5, the middle heat insulation cover 6, the middle cavity lower fixing cover 10 and the lower heat insulation cover 11 are connected through high-strength bolts, and therefore installation and maintenance are convenient.

As shown in fig. 3 and 4, the crucible supporting seat 21 is disposed at the bottom of the lower cavity thermal insulation layer 14 of the lower furnace body, and the bottom is fixed on the mounting base 23, the heating cavity is disposed on the crucible supporting seat 21, the crucible supporting seat 21 is disposed on the bottom surface of the supergravity test chamber, the crucible supporting seat 21 is used for supporting the weight of the whole furnace body, and the compressive stress generated under the action of the supergravity force, and is simultaneously thermal-insulated, so that the heat is prevented from being conducted to the bottom of the supergravity test device under the supergravity. The heating cavity comprises an upper heating cavity outer body 17, a lower heating cavity outer body 18, an upper heating furnace tube 19 and a lower heating furnace tube 20, the upper heating cavity outer body 17 and the lower heating cavity outer body 18 are of a sleeve structure, the upper heating cavity outer body 17 and the lower heating cavity outer body 18 are respectively positioned in upper and lower coaxial fixed butt joint, the bottom end of the lower heating cavity outer body 18 is fixed at the edge of a crucible supporting seat 21, the upper heating furnace tube 19 and the lower heating furnace tube 20 are respectively sleeved in the upper heating cavity outer body 17 and the lower heating cavity outer body 18, and mullite heat-insulating layers 16 are filled among an upper cavity heat-insulating layer 4 of the upper furnace body, a middle cavity heat-insulating layer 9 of the middle furnace body and a lower cavity heat-insulating layer 14 of the lower furnace body; as shown in fig. 4, the outer walls of the upper heating furnace tube 19 and the lower heating furnace tube 20 are both processed with a spiral groove 22-1, the spiral groove 22-1 is provided with a spiral heating element 22, as shown in fig. 5, the spiral groove 22-1 can effectively fix the heating element to prevent the heating element from sliding downwards under the supergravity, heat generated by the heating element 22 is uniformly radiated to the heating furnace tube composed of the upper heating furnace tube 19 and the lower heating furnace tube 20, and a high temperature region is formed in the center of the heating furnace tube composed of the upper heating furnace tube 19 and the lower heating furnace tube 20; the upper heating chamber external body 17 is used for installing an upper heating furnace tube 19, and the upper heating chamber external body 17 and the upper heating furnace tube 19 are used for heating the upper part of the device. The lower heating external body 18 is used for installing a lower heating furnace tube 20, and the lower heating external body 18 and the lower heating furnace tube 20 are used for heating the lower part of the device.

A plurality of through holes for connecting the upper heat insulation cover 1 are formed in the upper annular end face and the lower annular end face of the upper heating cavity outer body 17 and the lower heating cavity outer body 18 along the circumference, and a shaft connecting piece/rod connecting piece penetrates through the upper heat insulation cover 1 and is sleeved in the through holes in the same axial direction of the upper heating cavity outer body 17 and the lower heating cavity outer body 18.

The structural design of the heating furnace tube and the heating element 22 of the invention can prevent the heating element 22 from falling off under the environment of supergravity, and can adjust the heating effect by adjusting the screw pitches of different positions of the spiral groove.

The heating body 22 generates heat in the working process, the upper heating furnace tube 19 and the lower heating furnace tube 20 are heated through radiation, a high-temperature area is formed in the center of the heating furnace tube, the pitch of the spiral grooves 22-1 at different height positions is changed, the distance between the heating furnace tubes of the heating body 22 at different height positions is further changed, the cooling gas is cooled from the bottom of the crucible by matching with the temperature and the flow of the cooling gas introduced through the ventilation pipeline 21-1 of the crucible supporting seat 21, and a temperature gradient along the supergravity direction is formed.

The upper heating furnace tube 19 and the lower heating furnace tube 20 are made of ceramics with high strength and low heat conductivity coefficient.

In the concrete implementation of the invention, the selection of the heating element 22, the spiral groove pitch processed by the high-strength furnace tube 17 and the material type of the high-strength furnace tube 17 are required.

Selection of the heating element 22: the maximum allowable temperature and the requirement for the use environment are different for different heat-generating bodies 22, and the type of the heat-generating body 22 is determined in combination with the specific use condition of the apparatus, the maximum operating temperature, the vacuum environment and the hypergravity environment). Such as iron-chromium-aluminum electrothermal alloy wires, platinum wires and the like.

The spiral groove pitch processed by the upper heating furnace tube 19 and the lower heating furnace tube 20 is as follows: the heating element 22 is easily pulled up and deformed or even broken under an excessive stress. Besides the layout design of the heating element 22, a series of changing influences caused by the heating element 22 should be considered, for example, the heating element 22 is prevented from being broken when the deformation and movement are serious under the condition of supergravity, so that the overall operation of the device is influenced.

The material types of the upper heating furnace tube 19 and the lower heating furnace tube 20 are as follows: the material types of the upper heating furnace tube 19 and the lower heating furnace tube 20 are determined according to the type of the heat-generating body 22 and the temperature requirement for use. In order to prevent the deformation caused by the dead weight of the upper heating furnace tube 19 and the lower heating furnace tube 20 under the hypergravity, the furnace body of the high-temperature heating device is designed to be of a three-layer split type, and each layer is reinforced with an insulating layer independently.

As shown in fig. 6, a bearing frame, a signal collector and a wiring frame are further installed in the supergravity experimental cabin, material samples to be directionally solidified are installed in an upper heating furnace tube 19 and a lower heating furnace tube 20 of the high-temperature heating subsystem, a temperature sensor is also arranged, the temperature sensor is connected with the signal collector, and a lead output by the signal collector is connected with a weak signal conductive slip ring through the wiring frame and then is connected with a ground measurement and control center;

the high-temperature heating subsystem is provided with a strong current independent loop which controls heating bodies 22 at different height positions in the heating system to carry out high-temperature heating, and a strong current independent loop on the ground is connected into a wiring frame of the hypergravity experiment cabin through a centrifugal centrifuge main shaft conductive slip ring;

the high-temperature heating subsystem is provided with a cooling gas loop, the cooling gas independent loop controls the flow of the introduced cooling gas, and the cooling gas independent loop on the ground is connected with a cooling gas pipeline support and an exhaust pipe of the supergravity experiment chamber through a centrifugal centrifuge main shaft conductive slip ring.