High temperature mechanical properties of a laser melting deposited TiC/TA15 titanium matrix composite

The tensile behavior of a laser melting deposited TA15 titanium matrix composite containing 10 vol.% TiC reinforcement was studied at elevated temperatures. Results showed that the composite exhibited a superior strength but lower tensile elongation than monolithic matrix alloys at 873 K. As the test temperature increased from 873 K to 973 K, the ultimate tensile strength of the composite decreased from approximately 625 MPa to 342 MPa while the elongation rose from 7% to 18%. The internal damage phenomena were more evident at higher temperatures during tensile deformation. Although there was an increasing damage of interface debonding with the increasing test temperature, the fracture mechanism of the composite was predominantly controlled by particle cracking followed by ductile failure of the matrix in the whole temperature range of 873-973 K. This could be attributed to the strong bonding of the as-solidified TiC reinforcements with the matrix at high temperatures and the existence of prone-to-fracture carbides such as coarse unmelted TiC and clustered TiC particles in the composite.