Abstract: The behaviour of oxidation at elevated tem- peratures and fretting in the laser-alloyed layer of Ti-6Al-4V with the addition of Pr was studied. The results show that the addition of Pr changes the structure of oxide scale of Ti-6Al-4V,controls the short-range diffusion of oxygen to the scale/substrate interface and increases the adhe- sion and ductility of the scale,thus changing the oxidation kinetics and considerably reducing oxidation rate.The analysis of fretting test shows that the existence of high hardness layer in the al- loyed zone,fine dendrites perpendicular to the sur- face of the high hardness layer and the oxide scale produced during fretting at elevated temperatures are all beneficial to the improvement of wear resist- ance.

Key words: laser modification, Ti-6Al-4V alloy, oxidation, fretting