Fabrication and mechanical properties of Ti2AlC/TiAl composites with co-continuous network structure
(1. School of Mechanical Engineering, Guizhou University, Guiyang 550025, China;
2. School of Mechatronics Engineering, Guizhou Minzu University, Guiyang 550025, China)
2. School of Mechatronics Engineering, Guizhou Minzu University, Guiyang 550025, China)
Abstract: Ti2AlC/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 Ti2AlC was 20%, three-dimensional interpenetrating network structures were formed in the composites. Above 20%, Ti2AlC phase in the composites accumulated and grew to form thick skeletal networks. The microplastic deformation behavior of Ti2AlC 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.% Ti2AlC reached (900.9±45.0) MPa, which was 25.5% higher than that of TiAl matrix. In general, the co-continuous Ti2AlC/TiAl composite with excellent mechanical properties can be prepared by powder metallurgy method.
Key words: Ti2AlC/TiAl composites; co-continuous composites; hot pressing; strengthening mechanism