Laser material processing of nickel superalloy for improved erosion resistance

Abstract

A nickel-based superalloy was laser surface treated, and its erosion behavior was evaluated. The laser power and scan speed were varied in different levels to impart variations in microstructure and mechanical properties. The microstructure of specimens exhibited fine equiaxed grains to columnar structure at different parameters. A high cooling rate improved the hardness of the laser-treated specimen up to 603 HV0.3 compared to the base material hardness of 430 HV0.3. The rate of erosion increased linearly from 30° to 60° impingement angle and decreased at 75° impingement angle. The accumulation of the erodent inside the crater and the consequent absorbtion of the incident kinetic energy might have caused this reduction. The laser surface treated specimens exhibited ∼1.5 factor of improvement in high temperature erosion resistance. This was attributed to the minimized energy transfer from impinging particle to the substrate achieved through laser surface melting.