Fatigue behavior of surface modified Ti-6Al-4V alloy by double glow discharge plasma alloying

The Mo–N, Mo–C, Mo–Cr modified layers on Ti-6Al-4V alloy were prepared using a double glow discharge plasma alloying technology. Repeated impact tests were performed to evaluate the fatigue behavior of the plasma modified Ti-6Al-4V alloys. Results show that the three surface modified layers exhibited a different depth distribution in microhardness and different failure mode in repeated impact tests. Among the three modified layers the Mo–N has the best matching of impact fatigue strength with hardness.