Cold crucible directional solidification method for refining lamellar structure of TiAl alloy

A directional solidification, cold crucible technology, applied in the field of TiAl alloy processing, can solve problems such as coarsening, and achieve the effects of refining lamellar structure, increasing cooling rate, and improving room temperature plasticity

Inactive Publication Date: 2019-01-29
HARBIN INST OF TECH
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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem of increasing the cooling rate of the directionally solidified TiAl alloy while the directionally solidified TiAl alloy lamellar structure is coarse in the cold crucible continuous melting and casting process, and to provide a cold crucible directionally solidified TiAl alloy lamellar structure that is refined method

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  • Cold crucible directional solidification method for refining lamellar structure of TiAl alloy
  • Cold crucible directional solidification method for refining lamellar structure of TiAl alloy
  • Cold crucible directional solidification method for refining lamellar structure of TiAl alloy

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specific Embodiment approach 1

[0026] Specific embodiment 1: This embodiment records a cold crucible directional solidification method for refining TiAl alloy lamellar structure, and the method includes the following steps:

[0027] Step 1: preparing an alloy ingot whose composition is Ti-47Al-2Nb-2Cr-0.2C (unless otherwise specified, the composition is atomic percentage);

[0028] Step 2: processing the Ti-47Al-2Nb-2Cr-0.2C alloy ingot into a round bar for cold crucible directional solidification experiments;

[0029] Step 3: In the multi-functional cold crucible electromagnetically confined precise forming directional solidification equipment (quoted from the application number: 2018107732776), the round rod used for the directional solidification experiment is prepared into a TiAl intermetallic compound directional solidification sample;

[0030] Step 4: If figure 1 As shown, the directional solidification experiment was carried out on the TiAl intermetallic compound directional solidification sample, a...

specific Embodiment approach 2

[0032] Specific embodiment two: a cold crucible directional solidification method for refining TiAl alloy lamellar structure described in specific embodiment one, in step one, Ti-47Al-2Nb-2Cr-0.2C alloy is prepared by vacuum induction melting Ingot casting, the specific steps are as follows: according to the alloy composition, put titanium sponge, aluminum block, aluminum niobium master alloy, chromium sheet and C powder into a vacuum induction melting furnace (a small vacuum induction melting furnace of Consarc Company in the United States), and evacuate to 2.0 ×10 -3 ~2.5×10 -3 mbar, increase the smelting power to 150-160kW at a rate of 8-10kW / min and stop increasing the power, then smelt at a constant power for 3-5min to obtain an alloy melt, and then pour the melt into a furnace preheated to 350-400°C In the metal casting mold, a Ti-47Al-2Nb-2Cr-0.2C alloy ingot is obtained, and is naturally cooled to room temperature with the furnace.

specific Embodiment approach 3

[0033] Specific embodiment three: the cold crucible directional solidification method of a kind of refinement TiAl alloy lamellar structure described in specific embodiment one, in step two, adopt electric spark numerical control cutting machine tool (the numerical control DK7780 of Ningbo Haishu Zhongyuan Machine Tool Co., Ltd. fast walk wire machine tool) to process the Ti-47Al-2Nb-2Cr-0.2C alloy ingot into a round bar for directional solidification experiments, the wire speed of the EDM CNC cutting machine tool is 0.1m / s, and the diameter of the round bars for directional solidification experiments is 20mm.

[0034] Embodiment 4: A cold-crucible directional solidification method for refining the lamellar structure of TiAl alloy described in Embodiment 1. In step 4, a PtRh30-PtRh6 thermocouple with a diameter of Ф0.15 mm is inserted into the solid phase of the TiAl alloy , through the multi-channel temperature tester (JK-32U multi-channel temperature tester produced by Xingt...

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Abstract

The invention provides a cold crucible directional solidification method for refining the lamellar structure of TiAl alloy, and belongs to the technical field of TiAl alloy treatment. The method comprises the following steps of: preparing an alloy ingot having a composition of Ti-47Al-2Nb-2Cr-0.2C; processing the alloy ingot into a round bar for cold crucible directional solidification experiment;processing the round bar into a TiAl intermetallic compound directional solidification sample in multifunctional cold crucible electromagnetic confinement precise forming directional solidification equipment; carrying out directional solidification experiment on the TiAl intermetallic compound directional solidification sample, and measuring the temperature gradient in a TiAl alloy solid phase inthe experimentation process to obtain a cooling rate; and changing the cooling rate of the directionally solidified TiAl alloy to prepare the directionally solidified TiAl alloy having different lamellar thicknesses. By increasing the drawing rate in the directional solidification process of the cold crucible, the cooling rate of the directionally solidified TiAl alloy is increased, and the lamellar structure of the directionally solidified TiAl alloy is refined without destroying the directional solidification effect of the directionally solidified TiAl alloy; and the cold crucible directional solidification method has very important significance for improving the room-temperature ductility of the TiAl alloy and realizing the engineering application of the TiAl alloy.

Description

technical field [0001] The invention belongs to the technical field of TiAl alloy treatment, and in particular relates to a cold crucible directional solidification method for refining the lamellar structure of TiAl alloy. Background technique [0002] In recent years, the research on TiAl-based alloys has been paid more and more attention by researchers of superalloys in various countries. TiAl-based alloys have high specific strength, high specific stiffness, good high temperature oxidation resistance, creep resistance and hydrogen embrittlement resistance, which are not found in general metals and alloys, and are considered to be the next generation of new engine materials. TiAl alloys prepared by directional solidification can significantly improve their properties. During the directional solidification process, due to the slow cooling rate, the layer thickness of the directional solidified TiAl alloy is coarse. However, for directionally solidified TiAl alloys, sheet ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C14/00C22C1/03C22F3/02
CPCC22C1/03C22C14/00C22F3/02
Inventor 丁宏升王强陈瑞润郭景杰傅恒志
Owner HARBIN INST OF TECH
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