原位反应合成Nb掺杂Al2O3/TiAl复合材料的显微结构分析

利用Al-Ti-TiO2体系原位反应合成了Nb掺杂Al2O3／TiAl复合材料。借助XRD和SEM研究了Nb掺杂Al2O3／TiAl的显微结构以及Nb引入量对复合材料显微结构的影响。结果表明，复合材料由TiAl、Ti3Al、Al2O3、Nb和NbAl3相构成，细小Al2O3颗粒分布于基体晶粒交界处，存在一定的团聚；Nb元素引入量的高低，可调节产物中TiAl和Ti3Al的相对含量，随Nb含量的增大，TiAl含量逐渐减少，Ti3Al则逐渐增大；同时，基体晶粒和Al2O3颗粒均有所细化，且分布逐渐均匀，材料的均匀性得到改善。

Microstructure Analysis of Nb-Doped Al2O3/TiAl Composite Fabricated by In-Situ Reaction Synthesis

Nb-doped Al2O3/TiAl composites are fabricated by in-situ reaction synthesis by using exothermic reaction of Al- Ti - TiO2 system. The microstructure of Nb-doped A1203/TiA1 and effect of niobium content in composite on microstructure are experimentally investigated by means of XRD and SEM. The results indicate that the phases of composite are composed of TiAl, Ti3 Al, Al2O3, Nb and/or NbA13, and Al2O3 particles assemble on the boundary of matrix grains. There exists aggregation to some extent. TiAl content is decreased and Ti3Al increased with increasing niobium content. The matrix and Al2O3 particles are also refined with increasing niobium cbntent, resulting in a better homogeneity of composites.