Alloy design method for reducing directionally-solidified titanium aluminum alloy interface reaction

Abstract

The invention discloses an alloy design method for reducing directionally-solidified titanium aluminum alloy casting member and casting mold coating interface reaction, and belongs to a method for improving titanium aluminum alloy casting quality. The specific steps are as follows: designing TiAl alloys with different Nb contents for directional solidification process to obtain casting members; and using a microhardness tester to test Vickers microhardness to determine interface reaction layer thickness. A German brooke Quantax400-10 energy dispersive spectrometer is used for sample interface element distribution analysis, a German Brook D8AdanceX ray diffractometer is used for sample surface phase analysis, and a United States FEIQuanta TM250 scanning electron microscope is used for casting memberreaction layer and casting member matrix tissue morphology observation and analysis. Through corresponding analysis and test of the directionally-solidified titanium aluminum alloy casting members obtained by the alloy design, interfacial reaction degree can be obtained specifically and vividly, corresponding titanium aluminum alloy casting member quality can be well evaluated, and a TiAl alloy casting member with optimized Nb content can be obtained.

Description

Technical field [0001] This design studies an alloy design method that reduces the interface reaction between the directionally solidified titanium aluminum alloy castings and the mold coating, which is a method to improve the casting quality of titanium aluminum alloy. Background technique [0002] TiAl alloy has low density, high specific strength, high specific stiffness, good heat resistance, high temperature creep resistance and oxidation resistance. It is a lightweight superalloy with the best comprehensive performance, and is a super-high-speed aircraft and the next generation The material of choice for advanced aero-engines has therefore become the focus of research in lightweight alloys. [0003] At present, most TiAl-based alloys are produced by powder metallurgy technology, casting and ingot metallurgy technology. TiAl is a brittle intermetallic compound. The biggest obstacle to the practical use of TiAl alloys is the room temperature brittleness and difficult deformab...

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Problems solved by technology

[0007] Technical issues: This paper focuses on the titanium-aluminum alloy castings with different Nb contents obtained by directional solidification, and faces the problems of contamination and reaction with the casting coating material due to high temperature during the entire directional solidification process. Phase change and hardness distribution are used to evaluate the degree of interface reaction of corresponding castings, in order to find the best alloy composition ratio, thereby improving the quality of titanium-aluminum alloy castings and reducing the cost of subsequent processing

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