Method for realizing gamma-TiAl alloy refinement by accurately controlling metastable structure stabilization

A precise control and stabilization technology, applied in the direction of process efficiency improvement, energy efficiency improvement, etc., can solve the problems of difficult to control the size of lamellar clusters, increase the cracking tendency of ingots, and limited degree of refinement. The effect of improving performance, improving room temperature plasticity, and improving the degree of refinement

Active Publication Date: 2022-03-22
XI'AN PETROLEUM UNIVERSITY
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  • Abstract
  • Description
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Problems solved by technology

However, the existing casting industrial technology makes it difficult to control the grain size of lamellar clusters below 200 μm
The invention patent titled "A Heat Treatment Method for Refinement of TiAl Alloy Full Lamellar Cluster Size" (publication number: CN107904530A) adopts a two-step heat treatment process of quenching and tempering to refine TiAl alloy to obtain 20-100μm Fine-grained full-lamellar structure; however, this method uses a high-energy heat treatment method of quenching, which increases the cracking tendency of the ingot, and the degree of refinement is limited
The invention patent titled "A Multi-step Cyclic Heat Treatment Method for Improving the Mechanical Properties of Traditional Cast γ-TiAl Alloys" (publication number: CN105220096A) heat-treats the homogenized TiAl alloy continuously in the α+γ two-phase region; but the Method implementation takes too long and has limited granularity

Method used

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  • Method for realizing gamma-TiAl alloy refinement by accurately controlling metastable structure stabilization
  • Method for realizing gamma-TiAl alloy refinement by accurately controlling metastable structure stabilization
  • Method for realizing gamma-TiAl alloy refinement by accurately controlling metastable structure stabilization

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Embodiment 1

[0030] The γ-TiAl alloy of this embodiment is composed of the following atomic percentages: Al 48.5%, Nb 1.0%, Ta 3.0%, B 0.01%, and the balance is Ti, such as figure 1 As shown, the method of the present embodiment includes the following steps:

[0031] Step 1. Melting of the alloy ingot: the γ-TiAl alloy ingot is prepared by three smelting methods using the cold crucible vacuum induction melting method, and the O introduced into the γ-TiAl alloy ingot by atomic percentage does not exceed 0.05%, and the Fe does not exceed 0.05%. ;

[0032] Step 2, alloy homogenization treatment: put the γ-TiAl alloy ingot prepared in step 1 into a hot isostatic pressing furnace, and perform hot isostatic pressing treatment at a pressure of 200 MPa and a temperature of 1280 °C for 8 hours to obtain The dense TiAl alloy casting is then placed in a box-type heat treatment furnace for homogenization treatment. The specific process is as follows: firstly keep warm at 1430°C for 2 hours in the α s...

Embodiment 2

[0038] The γ-TiAl alloy of this embodiment is composed of the following atomic percentages: Al 47.5%, Nb 1.5%, Cr 1.0%, Ta 2.0%, B 0.05%, and the balance is Ti, such as figure 1 As shown, the method of the present embodiment includes the following steps:

[0039] Step 1. Melting of the alloy ingot: the γ-TiAl alloy ingot is prepared by three smelting methods using the cold crucible vacuum induction melting method, and the O introduced into the γ-TiAl alloy ingot by atomic percentage does not exceed 0.05%, and the Fe does not exceed 0.05%. ;

[0040] Step 2, alloy homogenization treatment: put the γ-TiAl alloy ingot prepared in step 1 into a hot isostatic pressing furnace, and perform hot isostatic pressing treatment at a pressure of 200 MPa and a temperature of 1260 °C for 6 hours to obtain The dense TiAl alloy casting is then placed in a box-type heat treatment furnace for homogenization treatment. The specific process is as follows: firstly keep warm at 1420°C for 2 hours i...

Embodiment 3

[0044] The γ-TiAl alloy of this embodiment is composed of the following atomic percentages: Al 47%, Nb 2.5%, Cr 2.0%, Ta 1.0%, B 0.1%, and the balance is Ti, such as figure 1 As shown, the method of the present embodiment includes the following steps:

[0045] Step 1. Melting of the alloy ingot: the γ-TiAl alloy ingot is prepared by three times of melting by the cold crucible vacuum induction melting method; impurities O and Fe are introduced in the process of the cold crucible vacuum induction melting method, and the γ-TiAl alloy ingot is calculated by atomic percentage. The O introduced into the TiAl alloy ingot does not exceed 0.05%, and the Fe does not exceed 0.05%;

[0046] Step 2, alloy homogenization treatment: put the γ-TiAl alloy ingot prepared in step 1 into a hot isostatic pressing furnace, and perform hot isostatic pressing treatment at a pressure of 200 MPa and a temperature of 1240 °C for 4 hours to obtain Dense TiAl alloy castings are then placed in a box-type ...

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Abstract

The invention discloses a method for refining gamma-TiAl alloy by accurately controlling metastable structure stabilization, the gamma-TiAl alloy comprises the following components in atomic percent: 47.0%-48.5% of Al, 1.0%-2.5% of Nb, 0.0%-2.0% of Cr, 1.0%-3.0% of Ta, 0.01%-0.1% of B and the balance of Ti, and the method comprises the following steps: 1, preparing a gamma-TiAl alloy ingot; 2, carrying out hot isostatic pressing and homogenization treatment; thirdly, heating and heat preservation are conducted in an alpha single-phase region and an alpha + gamma two-phase region in sequence, and the heat treatment process is circulated multiple times; and fourthly, heating and heat preservation are conducted in the alpha single-phase region, and the gamma-TiAl alloy of the fine-grain fully lamellar structure is obtained. According to the method, alloy element adding is combined with circulating heat treatment, the metastable structure is continuously regulated and controlled, grain refinement in the gamma-TiAl alloy is achieved, and the room-temperature plasticity, strength and other performance of the gamma-TiAl alloy are improved.

Description

technical field [0001] The invention belongs to the field of manufacturing light-weight high-temperature structural materials, and in particular relates to a method for precisely controlling the stabilization of metastable structures to realize the refinement of gamma-TiAl alloys. Background technique [0002] At present, there is an urgent demand for lightweight heat-resistant structural materials for aerospace power systems, automotive engines, and petrochemical high-temperature components, because the density of γ-TiAl alloys is only about 50% of that of Ni-based superalloys (about 3.8-4.3 g / cm 3 ), and has the advantages of high specific modulus, high creep resistance, good resistance to combustion, good oxidation resistance, and strong corrosion resistance, and has gradually become a candidate material for high-temperature components to replace high-temperature alloys to achieve substantial weight reduction. The second-generation casting γ-TiAl alloy 4822 alloy (Ti-48A...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C1/02C22C14/00C22C30/00C22F1/16C22F1/18
CPCC22C14/00C22C30/00C22C1/02C22F1/183C22F1/16Y02P10/25
Inventor 张可人霍苗
Owner XI'AN PETROLEUM UNIVERSITY
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