Al_2O_3/TiAl 复合材料的原位合成、结构与性能研究(英文)

以 Ti, Al, TiO2和 Nb2O5混合粉为原料,采用热压反应合成技术制备了 Al2O3/TiAl 复合材料。对复合材料的微观组织与力学性能进行了研究。结果表明:产物由γ-TiAl, α2-Ti3Al, Al2O3和 NbAl3相组成。原位反应形成的细小 Al2O3粒子主要分布在基体晶界处。随着 Nb2O5含量的增加,晶粒明显细化,Al2O3粒子呈弥散分布在基体中。最终形成了由γ和γ α2构成的特殊组织。随着 Nb2O5含量的增大,复合材料的硬度逐渐增大,抗弯强度和断裂韧性在 Nb2O5含量为 6 wt%时达到最大,分别为 398.5 MPa 和 6.99 MPa·m1/2。

Microstructure and Mechanical Properties of In-situ Synthesized Al2O3/TiAl Composites

Al2O3 particle-reinforced TiAI composites are successfully reaction-synthesized from the powder mixture of Ti, A1, TiO2, and Nb2O5, using the hot pressing reaction synthesis technique. The microstmcture and mechanical properties of the as-sintered products are investigated. It is found that in the as-sintered products consisting of γ-TiA1, α2-Ti3Al, Al2O3, and NbAl3 phases, the f'me Al2O3 particles tend to disperse on the grain boundaries. With the Nb2O5 content increasing, the grains are remarkably refined and the Al2O3 particles are dispersing more uniformly in the TiAI matrix, forming a partial lamellar structure containing γ and lamellar phases. The hardness of the in-situ composites increases gradually, and the bending strength and the fi-acture toughness of the as-sintered products reach the maxi-