阅读说明：本技术 一种基于金属液流冲击的金属组织细化方法 (Metal structure refining method based on metal liquid flow impact ) 是由 刘雪峰 李昂 万祥睿 于 2020-04-22 设计创作，主要内容包括：本发明公开了一种基于金属液流冲击的金属组织细化方法,属于金属制备技术领域。该方法包括如下步骤：在喷嘴中盛装金属熔体,并使所述金属熔体的温度维持在金属的液相线温度以上1-300℃；使所述金属熔体从所述喷嘴中以50-5000mm/s的速度呈连续金属液流的形式喷出并冲击到低温基板上；采用水平运动机构驱动所述喷嘴以1-1000mm/s的速度在水平方向运动,使所述金属液流冲击到所述低温基板表面后向所述金属液流移动的后方稳定堆积并且堆积的所述金属的固液界面与所述金属液流的距离始终维持恒定,最终制备得到具有均匀细小组织的金属件。本发明采用移动的金属液流冲击低温基板的方式直接制备出组织均匀细小的金属件,具有成本低、流程短和效率高等优点。(The invention discloses a metal structure refining method based on metal liquid flow impact, and belongs to the technical field of metal preparation. The method comprises the following steps: the method comprises the following steps of (1) containing a metal melt in a nozzle, and maintaining the temperature of the metal melt to be 1-300 ℃ above the liquidus temperature of metal; ejecting the metal melt from the nozzle in the form of a continuous metal liquid flow at a speed of 50-5000mm/s and impacting the metal melt on a low-temperature substrate; and driving the nozzle to move in the horizontal direction at the speed of 1-1000mm/s by adopting a horizontal movement mechanism, so that the metal liquid flow is stably accumulated behind the movement of the metal liquid flow after impacting the surface of the low-temperature substrate, and the distance between a solid-liquid interface of the accumulated metal and the metal liquid flow is always kept constant, and finally, the metal piece with uniform and fine tissues is prepared. The method directly prepares the metal piece with uniform and fine structure by adopting a mode of impacting the low-temperature substrate by the moving metal liquid flow, and has the advantages of low cost, short flow, high efficiency and the like.)

1. A metal structure refining method based on metal liquid flow impact is characterized by comprising the following steps:

the first step is as follows: the method comprises the following steps of (1) containing a metal melt in a nozzle, and maintaining the temperature of the metal melt to be 1-300 ℃ above the liquidus temperature of metal;

the second step is that: ejecting the metal melt from the nozzle in the form of a continuous metal liquid flow at a speed of 50-5000mm/s and impacting the metal melt on a low-temperature substrate;

the third step: and driving the nozzle to move in the horizontal direction at the speed of 1-1000mm/s by adopting a horizontal movement mechanism, so that the metal liquid flow is stably accumulated behind the movement of the metal liquid flow after impacting the surface of the low-temperature substrate, and the distance between a solid-liquid interface of the accumulated metal and the metal liquid flow is always kept constant, and finally, the metal piece with uniform and fine tissues is prepared.

2. The method for refining metal structure according to claim 1, wherein the diameter of the molten metal stream in the second step is 0.1 to 100 mm.

3. The method for refining metal structure according to claim 1, wherein in the first step, the step of maintaining the temperature of the metal melt 1-300 ℃ above the liquidus temperature of the metal is replaced with:

maintaining the temperature of the metal melt between the solidus temperature and the liquidus temperature of the metal.

4. The method for refining metal structure according to claim 1, wherein in the third step, the step of driving the nozzle to move in the horizontal direction at a speed of 1-1000mm/s using a horizontal movement mechanism is replaced with:

the nozzle is kept stationary and the low temperature substrate is moved in the horizontal direction at a speed of 1-1000 mm/s.

5. The method of claim 1, wherein the low-temperature substrate is made of at least one of pure copper, pure aluminum, a copper alloy, an aluminum alloy, stainless steel, aluminum nitride, and graphite.

6. The method for refining a metallic structure according to claim 5, wherein the low-temperature substrate is cooled by circulating cooling water or cooling medium around the low-temperature substrate.

7. The method for refining a metal structure according to claim 6, wherein the cooling medium is at least one of a liquid cooling medium, a gas cooling medium, or a solid cooling medium.

8. The method of claim 1, wherein the metal stream continuously impinges on the metal member and, under the influence of a cooling device, produces a large-sized metal product.

9. A metal part having a uniform fine structure, characterized in that it is produced by the method of refining a metal structure according to any one of claims 1 to 8.

Technical Field

The invention belongs to the technical field of metal preparation, and particularly relates to a metal structure refining method based on metal liquid flow impact.

Technical Field

The structure refinement can obviously improve the strength and toughness of the metal, and is an important means for improving the comprehensive performance of the metal and expanding the application field of the metal. The main principles of the refinement of the metal structure include increasing the nucleation rate, reducing the growth rate of crystal nuclei, increasing the breakage of dendrites, and recrystallization or phase transformation. Based on the above principle, the existing metal structure refining method mainly includes a chemical treatment method, a physical stirring/vibration refining method, a rapid solidification method, a deformation heat treatment method, and the like. The above methods can significantly refine the structure of the metal, but still have the following problems:

(1) the chemical treatment method introduces elements different from the chemical components of the metal, reduces the purity of the metal and increases the cost of metal preparation.

(2) The physical stirring/vibration refining method is easy to involve in gas when stirring/vibrating the metal melt, and has the defects of complicated stirring/vibrating device, high control difficulty and the like.

(3) The rapid solidification method has the defects of harsh realization conditions, low preparation efficiency and the like.

(4) The deformation heat treatment method consumes a large amount of energy, and the preparation process of the metal is complicated and the production cost is high.

Therefore, the method for refining the metal structure has the advantages of low development cost, short flow, high efficiency and no need of an additional stirring/vibrating device or element addition, and has important significance.

Disclosure of Invention

Aiming at the problems of high cost, long flow, low efficiency, additional stirring/vibrating devices or element addition and the like of the traditional metal structure refining method, the invention provides a method for directly preparing a metal piece with uniform and fine structure by adopting a moving metal liquid flow to impact a low-temperature substrate. The method combines the characteristic that after impacting a low-temperature substrate, a moving metal liquid flow can stably accumulate towards the rear of the moving metal liquid flow and the distance between a solid-liquid interface for accumulating metal and the metal liquid flow is always kept constant with the characteristic that the metal liquid flow impacts to enable a metal melt to always keep high-speed annular flow in front of the solid-liquid interface, so that the metal melt is fully nucleated under the action of a high-speed annular flow field, the nucleation rate is increased, the metal melt is always solidified at a higher speed under the action of the low-temperature substrate, the growth speed of crystal nuclei is reduced, and finally the metal piece with uniform and fine tissues is prepared.

According to a first aspect of the present invention, there is provided a method for refining a microstructure based on molten metal stream impact, comprising the steps of:

the first step is as follows: the nozzle is filled with the metal melt, the temperature of the metal melt is maintained to be 1-300 ℃ above the liquidus temperature of the metal, the components of the metal melt are uniform, the metal melt has better fluidity and required superheat degree, and the requirements of subsequent stable accumulation, high-speed annular flow and the like are met.

The second step is that: under the action of external force or self gravity, the metal melt is ejected from the nozzle in the form of continuous metal liquid flow at the speed of 50-5000mm/s and impacts on a low-temperature substrate, so that the metal liquid flow has the required initial flow speed after impacting the low-temperature substrate, and a high-speed annular flow field can be formed; the diameter of the metal liquid flow is 0.1-100mm, so that the metal liquid flow can be solidified at a higher speed after impacting the low-temperature substrate.

The third step: driving the nozzle to move in the horizontal direction at a speed of 1-1000mm/s by using a horizontal movement mechanism, so that the metal liquid flow is stably accumulated behind the movement of the metal liquid flow after impacting the surface of the low-temperature substrate, and the distance between a solid-liquid interface of the accumulated metal and the metal liquid flow is always kept constant; under the cooling action of the low-temperature substrate, the solid-liquid interface of the accumulated metal inclines to the rear upper part of the metal liquid flow and moves along with the metal liquid flow; in the metal melt between the solid-liquid interface and the metal liquid flow, a high-speed annular flow field formed by impacting the low-temperature substrate by the metal liquid flow exists, so that the metal melt in front of the solid-liquid interface is fully nucleated, the nucleation rate of the metal melt is increased, the metal melt is solidified at a high speed all the time under the action of the low-temperature substrate, the growth speed of crystal nuclei of the metal melt is reduced, and the metal piece with uniform and fine structures is finally prepared.

Further, the temperature of the metal melt is maintained between the solidus temperature and the liquidus temperature of the metal, and a solid-liquid mixture is obtained.

Further, the nozzle is kept still, and the low-temperature substrate moves in the horizontal direction at a speed of 1-1000 mm/s.

Furthermore, the low-temperature substrate is made of at least one of pure copper, pure aluminum, copper alloy, aluminum alloy, stainless steel, aluminum nitride or graphite, circulating cooling water is introduced into the low-temperature substrate or cooling media are adopted around the low-temperature substrate for cooling, and the cooling media are at least one of liquid cooling media, gas cooling media or solid cooling media.

Further, the metal liquid flow continuously impacts on the metal piece, and large-size metal products are prepared under the action of a cooling device.

According to a second aspect of the present invention, there is provided a metal part having a uniform fine structure, characterized in that the metal part is prepared by the method for refining a metal structure according to any one of the above aspects.

The invention has the following advantages:

1. the metal structure refining method based on metal liquid flow impact fully utilizes the stirring effect of the metal liquid flow on the metal melt after impacting the low-temperature substrate, and enables the metal liquid flow to always impact the substrate in a metal liquid flow moving mode, so that the nucleation rate of the metal melt is improved, and the prepared metal piece has uniform and fine isometric crystal structures.

2. The metal structure refining method based on metal liquid flow impact fully utilizes the characteristic that metal liquid flow is uniformly accumulated in a smaller volume behind the movement of the metal liquid flow after impacting the low-temperature substrate, and under the cooling effect of the low-temperature substrate, a solid-liquid interface is uniformly pushed along with the metal liquid flow, so that the cooling speed of metal melt is increased, the growth speed of crystal nuclei is reduced, and the structure of a metal piece is further uniformly refined.

3. The metal structure refining method based on metal liquid flow impact directly utilizes the flow of metal melt and the cooling of a low-temperature substrate to refine the structure, does not need an additional stirring/vibrating device or element addition, does not need subsequent thermomechanical treatment to further process the prepared metal piece, and has the advantages of low cost, short flow, high efficiency and the like.

Drawings

FIG. 1 is a process flow diagram of a microstructure refining method based on metal liquid flow impact according to the present invention.

Detailed Description

The present invention is described in detail below with reference to the following examples, which are necessary to point out here only for further illustration of the present invention and should not be construed as limiting the scope of the present invention, and those skilled in the art can make some insubstantial modifications and adaptations to the present invention based on the above-mentioned disclosure.