Effect of Fe on the environmental embrittlement of Co3Ti alloy

The mechanical properties of Co3Ti-based alloys were investigated. The tensile results show that the environment embrittlement of the alloy was completely suppressed when third element Fe was added to L12-type Co3Ti alloy. The AES result shows that the surface reaction of Co3Ti–Fe alloy with water vapor saturates at exposure of 2×10−3 Pa s, but it does not saturate at 0.1 Pa s exposure for Co3Ti alloy, and that the extent of the surface reaction of Co3Ti–Fe with water vapor is much smaller than that of Co3Ti at the same exposure. It illustrates that the beneficial effect of Fe in Co3Ti on the environmental embrittlement is attributed to its obvious reduction of the kinetics of the surface reaction with water vapor.