两相连续网络结构Ti_(2)AlC/TiAl复合材料的制备及力学性能

Fabrication and mechanical properties of Ti_(2)AlC/TiAl composites with co-continuous network structure

采用热压工艺制备不同体积分数的Ti_(2)AlC/TiAl复合材料,并研究其增强结构特征及力学性能。当增强相体积分数达到20%时,复合材料形成两相三维互贯通的结构;当增强相体积分数高于20%,复合材料中Ti_(2)AlC相聚集长大并形成粗大的骨骼网络。Ti_(2)AlC相的微观塑性变形行为(如扭折和层裂)能改善复合材料的断裂韧性,均匀细小的两相互贯通网络结构使复合材料得到进一步强化。20 vol.%Ti_(2)AlC/TiAl的复合材料的抗弯强度达到(900.9±45.0)MPa,比TiAl基体的提高25.5%。采用粉末冶金工艺能制备具有优异综合力学性能的两相连续网络结构的Ti_(2)AlC/TiAl复合材料。

Ti_(2)AlC/TiAl composites with different volume fractions were prepared by hot pressing technology,and their reinforced structural characteristics and mechanical properties were evaluated.The results showed that when the reinforced phase volume fraction of Ti_(2)AlC was 20%,three-dimensional interpenetrating network structures were formed in the composites.Above 20%,Ti_(2)AlC phase in the composites accumulated and grew to form thick skeletal networks.The microplastic deformation behavior of Ti_(2)AlC phase,such as kink band and delamination,improved the fracture toughness of the composites.Comparative analysis indicated that the uniform and small interconnecting network structures could further reinforce the composites.The bending strengths of composites prepared with 20 vol.%Ti_(2)AlC reached(900.9±45.0)MPa,which was 25.5% higher than that of TiAl matrix.In general,the co-continuous Ti_(2)AlC/TiAl composite with excellent mechanical properties can be prepared by powder metallurgy method.