Microstructure and Mechanical Properties of In-situ Synthesized Al2O3/TiAl Composites
Microstructure and Mechanical Properties of In-situ Synthesized Al2O3/TiAl Composites
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DOI：
10.1016/s1000-9361(08)60174-0
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发表时间：
2008-12-01
影响因子：
5.7
通讯作者：
Ai Taotao
中科院分区：
文献类型：
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作者：
Ai Taotao
以Ti、Al、TiO 2和Nb 2 O 5粉末混合物为原料，采用热压反应合成技术，成功反应合成了Al 2 O3颗粒增强TiAl复合材料。研究了烧结体的显微组织和力学性能。研究发现，在由γ-TiAl、α 2-Ti 3Al、Al 2 O3和NbAl 3相组成的烧结产物中，细小的Al 2 O3颗粒倾向于分散在晶界上。随着Nb 2 O 5含量的增加，晶粒明显细化，Al 2 O3颗粒在TiAl基体中的分散更加均匀，形成了含有γ相和片层相的部分片层组织。MPa.ml 2 O 5含量的增加，原位复合材料的硬度逐渐增加，当Nb 2 O 5含量增加到6wt%时，原位复合材料的抗弯强度和断裂韧性分别达到最大值398.5MPa和6.99（1/2）。
Al2O3 particle-reinforced TiAl composites are successfully reaction-synthesized from the powder mixture of Ti, Al, TiO2, and Nb2O5, using the hot pressing reaction synthesis technique. The microstructure and mechanical properties of the as-sintered products are investigated. It is found that in the as-sintered products consisting of gamma-TiAl, alpha 2-Ti3Al, Al2O3, and NbAl3 phases, the fine 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 TiAl matrix, forming a partial lamellar structure containing gamma and lamellar phases. The hardness of the in-situ composites increases gradually, and the bending strength and the fracture toughness of the as-sintered products reach the maximum value of 398.5 MPa and 6.99 MPa.ml(1/2), respectively, as the Nb2O5 content increases to 6 wt%.