Abstract
Surface properties of heat-treated Ti-6Al-4V alloy treated by heating-assisted ultrasonic rolling (HUR) were studied in this paper. The results showed that the sample treated by HUR at 140 degrees C exhibited the better microstructure and had relatively fine grains and uniform and dense dislocations, and the highest microhardness reached to 495 HV and had an increment of 70 HV compared to UR-treated sample at 25 degrees C. However, it showed the lower values of compressive residual stress than UR-treated sample at 25 degrees C. The high heating temperature increased the plastic deformation capacity of the materials during UR treatment. Meanwhile, it also promoted the release of residual stress. However, its surface roughness was slightly higher than UR-treated sample at 25 degrees C because of the lack of cold work hardening and the localized bonding behavior. Finally, HUR-treated sample at 140 degrees C had the lower coefficient of friction and wear rate compared to UR-treated sample at 25 degrees C. Therefore, it was deduced that the finer the grains were, the thicker the strengthening layer, and the higher mechanical properties of material surface layer had an important effect on surface friction and wear performance of the sample.