阅读说明：本技术 一种Mo-Nb-W-Zr合金单晶籽晶的培育方法 (Method for cultivating Mo-Nb-W-Zr alloy single crystal seed crystal ) 是由 李来平 胡忠武 殷涛 郭林江 郑晗煜 高选乔 任广鹏 杜明焕 张平祥 于 2019-10-28 设计创作，主要内容包括：本发明公开了一种Mo-Nb-W-Zr合金单晶籽晶的培育方法,该方法具体过程为：将Mo-Nb-W-Zr合金多晶坯料和Mo-Nb合金单晶籽晶晶棒放置于电子束区域熔炼设备熔炼室中并抽真空,然后加热熔接,再进行培育,得到Mo-Nb-W-Zr合金单晶籽晶。本发明采用电子束区域熔炼法,以Mo-Nb合金单晶作为籽晶直接培育Mo-Nb-W-Zr合金单晶籽晶,通过调节和控制熔接的加热功率、Mo-Nb-W-Zr合金多晶坯料的旋转速度R<Sub>多晶</Sub>和Mo-Nb合金单晶籽晶晶棒的旋转速度R<Sub>单晶</Sub>的比值以及培育时间,直接高效地培育出Mo-Nb-W-Zr合金单晶籽晶,缩短了工艺流程和培育周期,降低了培育成本。(the invention discloses a method for cultivating Mo-Nb-W-Zr alloy single crystal seed crystals, which comprises the following specific steps: placing the Mo-Nb-W-Zr alloy polycrystalline blank and the Mo-Nb alloy single crystal seed crystal ingot into a melting chamber of electron beam zone melting equipment, vacuumizing, heating, welding and cultivating to obtain the Mo-Nb-W-Zr alloy single crystal seed crystal. The invention adopts an electron beam zone melting method, uses Mo-Nb alloy single crystal as seed crystal to directly cultivate Mo-Nb-W-Zr alloy single crystal seed crystal, and adjusts and controls the heating power of welding and the rotation speed R of Mo-Nb-W-Zr alloy polycrystalline blank Polycrystalline And the rotation speed R of the Mo-Nb alloy single crystal seed crystal rod Single crystal The ratio and the cultivation time of the Mo-Nb-W-Zr alloy single crystal seed crystal are directly and efficiently cultivated, the process flow and the cultivation period are shortened, and the cultivation cost is reduced.)

1. A method for cultivating Mo-Nb-W-Zr alloy single crystal seeds is characterized by comprising the following steps:

Step one, coaxially placing Mo-Nb-W-Zr alloy polycrystalline blank and Mo-Nb alloy single crystal seed crystal rod on a displacement mechanism clamp in a melting chamber of electron beam zone melting equipment, wherein the displacement mechanism clamp and the cathode filament ring are both positioned at the central position of a cathode filament circle, and then carrying out vacuum-pumping treatment on the melting chamber until the vacuum degree is not more than 1.0 multiplied by 10^-3Pa; the diameter of the Mo-Nb alloy single crystal seed crystal rod is 20-40 mm;

Step two, heating the Mo-Nb-W-Zr alloy polycrystalline blank and the Mo-Nb alloy single crystal seed crystal rod in the smelting chamber subjected to the vacuumizing treatment in the step one by controlling input high-voltage working voltage and electron beam current, welding the Mo-Nb-W-Zr alloy polycrystalline blank and the Mo-Nb alloy single crystal seed crystal rod when the heating power is 5.5 kW-6.5 kW, and then adjusting the rotation speed R of the Mo-Nb-W-Zr alloy polycrystalline blank_{Polycrystalline}And the rotation speed R of the Mo-Nb alloy single crystal seed crystal rod_{Single crystal}Culturing for 15min to 30min according to the ratio to obtain Mo-Nb-W-Zr alloy single crystal seed crystals; the crystal orientation of the Mo-Nb-W-Zr alloy single crystal seed crystal is consistent with that of the Mo-Nb alloy single crystal seed crystal rod, and the R is_{Polycrystalline}/R_{Single crystal}0.8 to 1.2.

2. The method for growing the Mo-Nb-W-Zr alloy single crystal seeds of claim 1, wherein in the second step, the Mo-Nb-W-Zr alloy single crystal seeds are grown on the end surface of the Mo-Nb alloy single crystal seed crystal rod.

3. The method for cultivating a Mo-Nb-W-Zr alloy single crystal seed crystal according to claim 1, wherein in the second step, the Mo-Nb-W-Zr alloy single crystal seed crystal contains Nb 0.1-20 wt%, W0.1-1.0 wt%, and Zr 0.01-1.0 wt%.

Technical Field

The invention belongs to the technical field of seed crystal preparation, and particularly relates to a method for cultivating Mo-Nb-W-Zr alloy single crystal seed crystals.

Background

The method for growing single crystal seeds is various, such as the Czochralski method, the strain annealing method, the vapor phase crystallization method, the electrolysis method, the distillation method, the zone melting method, and the like, and among them, the methods suitable for growing refractory metal single crystal seeds are only the Czochralski method, the strain annealing method, and the zone melting method.

The essence of the Czochralski method for cultivating the metal single crystal seed crystal is that a metal wire with a very thin diameter is immersed into a melt in a shallow mode, the melt is gradually crystallized on the surface of the lower end face of the metal wire with a specific tissue by controlling parameters such as temperature gradient and the like, and the metal single crystal seed crystal is cultivated through repeated solidification for many times. The Czochralski method has the disadvantages that the number of crystal grains in the structure of the lower end surface of the metal wire is required to be small, the cultivation frequency is high (not less than 5 times), the cultivation time is long, a proper crucible material is required, and meanwhile, the crucible material can pollute a melt, which is not beneficial to the improvement of the purity of the refractory metal material and the cultivation of the single crystal seed crystal.

The strain annealing method is a method for growing single crystal seed crystals based on the occurrence of polymorphic solid phase transformation or recrystallization of metals. According to the method, the metal polycrystalline material needs to be annealed at high temperature for a very long time, the single crystal seed crystal cultivation efficiency is extremely low, and the diameter of the cultivated refractory metal single crystal seed crystal is not more than 3 mm.

The essence of the method for culturing the refractory metal single crystal seed crystal by the zone melting method is that a melting zone is heated by means of electron beams in a high vacuum environment, the stability of the melting zone is kept by the balance of surface tension and gravity, and the refractory metal single crystal seed crystal is cultured by controlling the temperature gradient, the chemical composition gradient and the like of the melting zone through repeated tests in a certain time. Since the 50 s of the last century, research work for growing refractory metal single crystal seeds by electron beam zone melting has begun to be explored and made better progress. Since the last 60 years, China began to explore the research of growing refractory metal single crystal seed crystals by electron beam zone-melting smelting, and successively grown pure W single crystal seed crystals, pure Mo single crystal seed crystals, pure Nb single crystal seed crystals and Mo-Nb alloy single crystal seed crystals. However, no matter which method is adopted to cultivate the refractory metal single crystal seed crystal, the cultivation process is very complicated and long, the efficiency is low, the cost is high, and the method is only limited to the cultivation of the single crystal seed crystal of the pure metal or the binary infinite solid solution alloy system with simple components.

At present, only Russia, China and the United states can cultivate large-size refractory metal single crystal seed crystals internationally, and the method is limited to pure refractory metal single crystals and binary alloy system single crystal seed crystals. For the cultivation work of ternary and above refractory metal alloy single crystal seed crystals, Russia and America are still in the stage of attack. However, since the fields of application of these materials are important and special, Russia and the United states both have technical blockages in China. Therefore, China can only develop the development of the multi-element refractory metal single crystal material by independent innovation, including the cultivation of the multi-element refractory metal single crystal seed crystals and the like.

Disclosure of Invention

The invention aims to solve the technical problem of providing a method for cultivating Mo-Nb-W-Zr alloy single crystal seed crystals aiming at the defects of the prior art. The method adopts an electron beam zone melting method, uses Mo-Nb alloy single crystal as seed crystal to directly cultivate Mo-Nb-W-Zr alloy single crystal seed crystal, and adjusts and controls the heating power of welding and the rotation speed R of Mo-Nb-W-Zr alloy polycrystalline blank_{Polycrystalline}And the rotation speed R of the Mo-Nb alloy single crystal seed crystal rod_{Single crystal}The ratio and the cultivation time of the Mo-Nb-W-Zr alloy single crystal seed crystal are directly and efficiently cultivated, the process flow and the cultivation period are shortened, and the cultivation cost is reduced.

In order to solve the technical problems, the invention adopts the technical scheme that: a method for cultivating Mo-Nb-W-Zr alloy single crystal seeds is characterized by comprising the following steps:

Step one, coaxially placing Mo-Nb-W-Zr alloy polycrystalline blank and Mo-Nb alloy single crystal seed crystal rod in an electron beam region for meltingThe displacement mechanism clamps in the smelting chamber of the smelting equipment are all positioned at the central position of the cathode filament circle, and then the smelting chamber is vacuumized until the vacuum degree is not more than 1.0 multiplied by 10^-3Pa; the diameter of the Mo-Nb alloy single crystal seed crystal rod is 20-40 mm;

Step two, heating the Mo-Nb-W-Zr alloy polycrystalline blank and the Mo-Nb alloy single crystal seed crystal rod in the smelting chamber subjected to the vacuumizing treatment in the step one by controlling input high-voltage working voltage and electron beam current, welding the Mo-Nb-W-Zr alloy polycrystalline blank and the Mo-Nb alloy single crystal seed crystal rod when the heating power is 5.5 kW-6.5 kW, and then adjusting the rotation speed R of the Mo-Nb-W-Zr alloy polycrystalline blank_{Polycrystalline}And the rotation speed R of the Mo-Nb alloy single crystal seed crystal rod_{Single crystal}Culturing for 15min to 30min according to the ratio to obtain Mo-Nb-W-Zr alloy single crystal seed crystals; the crystal orientation of the Mo-Nb-W-Zr alloy single crystal seed crystal is consistent with that of the Mo-Nb alloy single crystal seed crystal rod, and the R is_{Polycrystalline}/R_{Single crystal}0.8 to 1.2.

The invention adopts an electron beam zone melting method, uses Mo-Nb alloy single crystal as seed crystal to directly cultivate Mo-Nb-W-Zr alloy single crystal seed crystal, and adjusts and controls the heating power of welding and the rotation speed R of Mo-Nb-W-Zr alloy polycrystalline blank_{polycrystalline}And the rotation speed R of the Mo-Nb alloy single crystal seed crystal rod_{Single crystal}The ratio of the Mo to the Nb to the W to the Zr and the cultivation time, and directly and efficiently cultivating the Mo-Nb-W-Zr alloy single crystal seed crystal. According to the invention, firstly, by adjusting and controlling the heating power of fusion, segregation of alloy elements W and Zr caused by overlarge viscosity of a fusion zone which is not beneficial to diffusion of the alloy elements W and Zr in the Mo-Nb-W-Zr alloy polycrystalline blank in the fusion process is avoided, meanwhile, the temperature gradient of the fusion zone is also prevented from being increased due to the overlarge viscosity of the fusion zone, and the cultivation and growth of Mo-Nb-W-Zr alloy single crystal seed crystals are ensured; then regulating and controlling the rotation speed R of the Mo-Nb-W-Zr alloy polycrystalline blank_{Polycrystalline}And the rotation speed R of the Mo-Nb alloy single crystal seed crystal rod_{Single crystal}The rotation speed R of the Mo-Nb-W-Zr alloy polycrystalline blank is avoided_{Polycrystalline}Too slow, and Mo-Nb-W alloy polycrystalline blank melting zone internal alloy elements Nb, W and Zr are unevenly distributed easily to cause Mo-Nb-Wthe-Zr alloy single crystal seed crystal forms a polycrystalline structure, and the rotation speed R of the Mo-Nb-W-Zr alloy polycrystalline blank is avoided_{Polycrystalline}the temperature gradient of the melting zone fluctuates violently due to the excessive rapidness and the damage to the balance state of the force of the melting zone, so that the Mo-Nb-W-Zr alloy single crystal seed crystal cultivation fails; the alloy elements in the melting zone are uniformly distributed by regulating and controlling the cultivation time, and the phenomenon that the segregation of the alloy elements damages the formation of a single crystal tissue due to the over-short cultivation time is avoided, so that the smooth cultivation of the single crystal seed crystal is ensured, and meanwhile, the phenomena that the viscosity of the melting zone is reduced due to the over-long cultivation time and the over-large accumulated heat in the melting zone damages the balance state of the force of the melting zone to cause the collapse of the melting zone and further the Mo-Nb-W-Zr alloy single crystal seed crystal cannot be cultivated are avoided; in addition, by utilizing the genetic characteristics of the crystal, the crystal orientation and the quality of the Mo-Nb-W-Zr alloy single crystal seed crystal are ensured by selecting and controlling the crystal orientation of the Mo-Nb alloy single crystal seed crystal and combining the cultivation process.

The method for cultivating the Mo-Nb-W-Zr alloy single crystal seed is characterized in that in the second step, the Mo-Nb-W-Zr alloy single crystal seed is obtained by cultivating the Mo-Nb alloy single crystal seed on the end face of the Mo-Nb alloy single crystal seed crystal rod. Heating the lower end face of the Mo-Nb-W-Zr alloy polycrystalline blank by adopting an electron beam, converting the lower end face of the Mo-Nb-W-Zr alloy polycrystalline blank from a solid state into a liquid state, keeping the lower end face of the Mo-Nb-W-Zr alloy polycrystalline blank in the liquid state by controlling power, melting the upper end face of the Mo-Nb alloy single crystal seed crystal rod by controlling the electron beam, converting the upper end face of the Mo-Nb alloy single crystal seed crystal rod from the solid state into the liquid state, fusing the lower end face of the Mo-Nb-W-Zr alloy polycrystalline blank with the upper end face of the Mo-Nb alloy single crystal seed crystal rod by utilizing the action of gravity, and then culturing, thereby obtaining the Mo-Nb-W-Zr alloy single crystal seed crystal by culturing the end face of.

The method for cultivating the Mo-Nb-W-Zr alloy single crystal seed crystal is characterized in that in the second step, the mass content of Nb in the Mo-Nb-W-Zr alloy single crystal seed crystal is 0.1-20%, the mass content of W is 0.1-1.0%, and the mass content of Zr is 0.01-1.0%. The Mo-Nb-W-Zr alloy single crystal seed crystal with the composition is beneficial to the smooth generation of a Mo-Nb-W-Zr alloy single crystal seed crystal bar.

Compared with the prior art, the invention has the following advantages:

1. The invention adopts an electron beam zone melting method, uses Mo-Nb alloy single crystal as seed crystal to directly cultivate Mo-Nb-W-Zr alloy single crystal seed crystal, and adjusts and controls the heating power of welding and the rotation speed R of Mo-Nb-W-Zr alloy polycrystalline blank_{polycrystalline}and the rotation speed R of the Mo-Nb alloy single crystal seed crystal rod_{Single crystal}the ratio and the cultivation time of the Mo-Nb-W-Zr alloy single crystal seed crystal are directly and efficiently cultivated, the process flow and the cultivation period are shortened, and the cultivation cost is reduced.

2. The diameter of the Mo-Nb-W-Zr alloy single crystal seed crystal bar prepared by the invention is 20-40 mm, and the crystal orientation deviation angle is stably controlled at 0-2 degrees.

3. The invention has simple process and higher efficiency and is suitable for popularization.

The technical solution of the present invention is further described in detail by examples below.

Detailed Description