Repeated Impact Resistance of Cr-Mo Surface Alloying Layers on Ti6Al4V Alloy

Cr-Mo surface alloying modified layers on Ti6Al4V alloy were prepared using double glow discharge plasma alloying technique. The surface hardness and the resistance ability of repeated impact of the layers were measured using Knoop hardness test and repeated impact test respectively. The results show that the surface hardness of the modified samples was significantly improved due to the deposited layer containing Cr1.93Ti1.07, Cr2Ti, FeCrMo, and Cr2Ti4O11 compounds. However, it was found that heavy peeling occurred on the Cr-Mo alloying modified layers after repeated impact test due to these brittle phases formed in plasma alloying process. Brittle phases appeared in the surface modified layer, such as intermetallic compounds, contribute to hardness enhancement and wear properties, but may be detrimental to impact resistance.