新型超轻TiAl多孔材料的制备及其力学性能

Processing and mechanical property of the novel TiAl with high porosity

摘要:

基于化学反应造孔和物理占位造孔的联合作用,发展了一种新型TiAl金属间化合物多孔材料的制备工艺,工艺具体可用均混、压制、脱溶、烧结四个阶段来描述。该工艺实现了双孔结构TiAl多孔材料的制备,其中微米孔由Kirkendall效应产生,毫米孔由物理占位造孔颗粒实现。材料具有完全的通孔结构,孔洞分布均匀,且孔隙率、孔径、孔型、孔结构可控,最高孔隙率可达90%。准静态压缩力学性能测试表明,TiAl多孔材料属于脆性多孔材料,具有典型的脆性破坏断裂机制,其屈服强度与相对密度的关系可通过正六面体单胞模型来理解。

Abstract:

A novel preparation process has been developed to fabricate TiAl intermetallic compound porous materials based on the combination effect of making pores arising from the chemical reaction and physical space occupation. The technique is mainly consisted of four stages describled as mixing, compacting, dissolution and sintering. The typical double pore structures of the TiAl porous materials were successfully achieved, where the micron pore is associated with the Kirkendall effect and the millimeter pore comes from the space holders. The TiAl porous materials exhibit a thorough open-cellular structure and a perfect homogeneous distribution. Moreover, the porosity, pore size, pore shape, pore structure can be tailored as designed, and the maximum of porosity even reaches 90%. The results of quasi-state compression tests indicate that the TiAl porous materials are typical brittle porous materials with corresponding brittle fracture failure mechanism. The relationship between yield strength and relative density can be understood in terms of the cube cell modle.