元素粉末法制备TiAl金属间化合物的研究进展

Research Progress of TiAl Intermetallic Alloy Fabricated by Elemental Powder Metallurgy Method

元素粉末冶金因具有成本低、制备的合金组织均匀细小等优点而受到广泛关注。简要介绍了元素粉末法制备TiAl合金的研究进展,主要从反应机理、致密化行为和力学性能等方面进行综述。研究表明,Ti与Al元素的反应由扩散控制,借助TiAl_(3)和TiAl_(2)等中间相最终得到Ti_(3)Al和TiAl相共存的反应产物。在高Nb-TiAl合金的Ti-Al-Nb三元系中,Nb元素主要通过形成中间产物——Nb-Al化合物最终均匀分布在基体相中。从原料和工艺两个角度总结了元素粉末法制备TiAl合金过程中影响致密化的因素,介绍了提高元素粉末法制备TiAl合金的热加工和力学性能的方法,总结了近年来元素粉末法制备TiAl合金的力学性能研究成果。目前来看,元素粉末法制备的TiAl合金力学性能已达到变形合金的水平。

Elemental powder metallurgy method has attracted extensive attention because of its low cost and the uniform and fine microstructure of the prepared alloy.This paper briefly introduces the progress of preparation of TiAl alloy by elemental powder metallurgy method,mainly focus on the reaction mechanism,densification behavior and mechanical properties.Studies have shown that the reaction between Ti and Al is a diffusion-controlled process in which the intermediate phases such as TiAl_(3) and TiAl_(2) are obtained,while the final reaction products are the co-existed Ti_(3)Al and TiAl.In the Ti-Al-Nb ternary system for high Nb-TiAl alloy,the Nb element is mainly transformed into intermediate product of Nb-Al compounds,and then distributed uniformly in the matrix phase.The factors affecting the densification of TiAl alloy are summarized from the perspective of raw materials and sintering process,as well as the methods to improve the thermal workability and mechanical properties.The recent research results on mechanical properties of the TiAl alloy prepared by elemental powder metallurgy method are provided.At present,its mechanical properties can reach the level of forged TiAl alloys.