Gamma-based high-temperature TiAl composite material coaxial powder feeding 3D printing preparation method

Abstract

The invention discloses a coaxial powder feeding 3D printing preparation method of a gamma-based high-temperature TiAl composite material. Si3N4 is used as a silicon source and a nitrogen source and is subjected to ball-milling mixing with pre-alloyed powder Ti-55Al-7.5 Nb with high Al content, and 3D printing is performed to obtain the in-situ synthesized micro-nano particle net-shaped coated synergistically reinforced TiAl-based composite material. And micro-nano-scale Ti2AlN and Ti5Si3 reinforcing phases are dispersed and distributed in the matrix of the composite material. According to the TiAl-based composite material, the Ti2AlN and Ti5Si3 reinforcing phases with the micron scale are 5-10 [mu] m, the Ti5Si3 reinforcing phase with the nano scale is 50-100 nm, the two reinforcing phases have the reinforcing effect on the TiAl-based composite material, and the nano-scale Ti5Si3 reinforcing phase is almost separated out of the grain boundary of matrix gamma grains and plays a role in pinning the grain boundary. Through precipitation coexistence of two different-scale reinforced phases, the high-temperature structure stability of the gamma-based TiAl composite material is further improved, the problems of high energy consumption, serious environmental pollution and the like of TiAl alloy preparation by a traditional process are solved, meanwhile, the problem of high-temperature structure degradation of TiAl alloy widely applied at present is solved, the method can be widely realized in industry, and the method is suitable for industrial production. Therefore, the method has a wide application prospect.

Description

technical field [0001] The invention belongs to the field of preparation of TiAl and its metal-based composite materials, and in particular relates to an in-situ self-generated Ti 5 Si 3 and Ti 2 Preparation method for coaxial powder feeding 3D printing of AlN multiphase synergistic γ-based high temperature TiAl composites. Background technique [0002] With the proposal of carbon neutralization, the energy, transportation and aviation industries are also facing great challenges, and structural materials occupy a very important position in the industry, especially high-temperature structural materials used in aerospace. For aerospace materials, high temperature resistance and light weight have always been the goals pursued by scholars at home and abroad. As a new type of intermetallic compound structural material, TiAl alloy has low density (compared to nickel-based superalloys with a weight reduction effect of 40% to 50%), high strength, high modulus, combustion resistan...

AI Technical Summary

Problems solved by technology

The dual-phase structure will show structural degradation during long-term use at high temperature, that is, the grain growth of some structures and the occurrence of solid-state phase transformation, and the high-temperature creep performance will drop sharply

Moreover, most of the currently used TiAl alloys are formed by casting or plastic deformation. The cast TiAl grains are relatively coarse, and the structure segregation is relatively serious, which seriously affects the later use.

Although the deformed structure is relatively small and relatively uniform, the deformation process of TiAl alloy is extremely complicated, and it needs to go through processes such as ingot casting, hot isostatic pressing, sheath extrusion, and high-temperature forging, and high-temperature forging requires expensive forging machines and forging molds , the process is complicated, requires a lot of manpower and material resources, and the energy consumption is very serious

[0004] In order to solve the problems of high energy consumption and serious environmental pollution in the preparation of TiAl alloys by traditional processes, and at the same time solve the problem of microstructure degradation of TiAl alloys widely used at high temperatures, it is urgent to design a new type of TiAl-based composite material and its preparation and processing technology. No phase change occurs during high temperature use, avoiding tissue degradation. The corresponding preparation and processing technology is suitable for brittle TiAl alloy materials on the one hand, and meets the process requirements of low-carbon and environmental protection on the other hand.

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