Microstructure and mechanical properties of Cr12MoV by ultrasonic vibration-assisted laser surface melting

The effects of laser surface melting assisted by ultrasonic vibration on the microstructure and mechanical properties of Cr12MoV were investigated. Results indicated that the original coarse columnar dendrite can be converted into a fine dendritic and equiaxed. The average microhardness increase from 389HV(0.2) to 427HV(0.2) resulted from the effect of grain refinement. The friction coefficient was lower than the melted layer without ultrasonic vibration and substrate. Under the same experimental conditions, the width and depth of wear scar were decreased by 19% and 25% than that of without ultrasonic vibration, respectively. The wear mechanism from severe adhesive wear into slight abrasive wear under the action of ultrasonic vibration. Experimental results revealed that melted layer fabricated by ultrasonic vibration exhibit finer and more uniform microstructure as well as superior tribological properties.