Interfacial study of continuous Mo fiber reinforced tial matrix composite

ABSTRACT Composite reinforced with continuous Mo fiber reinforcement was prepared by pre-placing fiber and vacuum casting. The microstructure, concentration and hardness profiles across the interface in ascast and HIPed samples were investigated. The results showed that the interfacial phases formed between Mo fiber and TiAl matrix in both materials. These include two intermetallic phases, p-(Ti, Mo)3Al and /3-(Ti, Mo)Al with a sequence of Mo-p-Y (or y + 01). Boundaries of Mo/,0, and p/ are smooth, while the /3/y + 02 interfaces are serrated with the serration parallel to the lamellar laths in the casting condition. The serration disappeared after HIPing, and the boundary between and y becomes smooth. The area containing p-(Ti, Mo)3Al and /î-(Ti, Mo)Al is harder than the TiAl matrix and the Mo fiber. Mo atoms appear to diffuse faster in a2-Ti3Al than in y-TiAl.