The Relationship of TiCp/Titanium Based Composites Creep Mechanism and Microstructure

The creep properties and fracture microstructure of TiCp reinforced Ti based composites were investigated, while creep mechanism being discussed in this article. The thermal creep properties in different heat-treatment conditions were tested, and the microstructures and fracture were observed by SEM. The results show something as follows: Firstly, there is somewhat mismatching between particles and matrix for their difference of the properties. Because much more dislocation resulted by mismatching piled up on the interfaces of TiCp/Titanium, transmitting the stresses loaded on matrix to particles, dislocation pile-up stress field hindered the after dislocation movement to decrease creep deformation. Secondly, TP-650 showed binary microstructure with lower initial alpha phase, which often lead to a little residual deformation of creep. The creep fracture microstructures were cavity-shape fracture, and micro-crack occurred on the edges of the fracture. Thirdly, the creep deformation mechanism is mainly dislocation slide, and fracture seemed to be candy appearance along the grain boundary.