TiAl alloy and preparation method thereof

Abstract

The invention belongs to the field of TiAl intermetallic compounds, and relates to forging TiAl alloy which is mainly applied to manufacturing of aero-engine blades, can be used for a long time at thetemperature being 700-800 DEG C, and is high in plasticity, high in strength, high-temperature-resistant and fatigue-resistant and a preparation method of the forging TiAl alloy. The TiAl alloy is added with beta stable elements such as Cr, Nb, Ta, W and Mo, and is further added with a small amount of interstitial elements such as B and Si. The forging TiAl alloy is characterized in that the TiAlalloy comprises the following components in percentages by atoms: 42-47% of Al, 3-6% of Nb, 1-2% of Cr, 0.1-0.5% of Ta, 0-0.2% of W, 0-0.2% of Mo, 0-0.2% of B, 0-0.2% of Si and the balance of Ti andinevitable impurities, wherein O content is less than or equal to 0.1 wt%, N content is less than or equal to 0.015 wt%, H content is less than or equal to 0.01 wt%, and Fe content is less than or equal to 0.08 wt%. After the various beta stable elements are combined and matched, the total adding amount is calculated according to a [Nb] equivalent formula and requires to be controlled between 6 and 11. The TiAl alloy can work at the temperature being 700-800 DEG C for a long time, can be used for manufacturing parts such as aero-engine compressor blades and low-pressure turbine blades, can also be used for manufacturing high-temperature-resistant structures such as supersonic aircrafts, and can be used for a short time at the temperature being 900-1000 DEG C.

Description

technical field [0001] The invention belongs to the field of TiAl intermetallic compounds, and relates to a forged TiAl alloy with high plasticity, high strength, high temperature resistance and fatigue resistance, which is mainly used in the manufacture of aeroengine blades and can be used for a long time at 700°C to 800°C, and a preparation method thereof. Background technique [0002] TiAl-based intermetallic compound alloy has excellent properties such as low density, high specific strength, high specific modulus, high creep resistance, oxidation resistance, and combustion resistance, so it has become a very potential light-weight and high-temperature resistant structural material. Key materials for next-generation high thrust-to-weight ratio aeroengines. Judging from the current development of TiAl alloys, cast TiAl alloys have developed rapidly. For example, blade parts of cast Ti-48-2Cr-2Nb alloys have begun to be used in aero-engines. However, the degree of alloying...

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Problems solved by technology

However, since TiAl alloy is a long-range ordered intermetallic compound material, γ and α in TiAl alloy 2 The two phases are respectively ordered L1 0 and D0 19 Crystal structure, most of the β-phase stabilizing elements are in γ and α 2 The solid solubility in the two phases is relatively low. When the addition of β-stabilizing elements exceeds the solid solubility limit, a B2 phase with an ordered body-centered cubic crystal structure will be formed in the TiAl alloy. When the B2 phase content is high, It will significantly reduce the plasticity of TiAl alloy at room temperature, making it impossible to apply

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