ENVIRONMENTAL-EFFECTS ON THE ROOM-TEMPERATURE DUCTILITY OF A TIAL BASED ALLOY

The effects of different environments and strain rates on the room tem perature ductility of a TiAl based alloy with the composition Ti-46Al- 2Cr-0.2Si-0.1Nd have been investigated in this paper. The results show that the TiAl based alloy is susceptible to environmental embrittleme nt at room temperature. The tensile ductility of the TiAl based alloy in different test environments decreases in the sequence of oxygen > a ir > hydrogen > argon saturated with water vapor. The ductility is als o sensitive to strain rate. It increases with increasing strain rate w hen tested in hydrogen gas. Both H2O and H-2 cause environmental embri ttlement, with the former being a more potent embrittler.