Tribology Characteristics of Ultrasonic Impact Treated Co-Based L-۶۰۵ Superalloy

This study investigates the effect of ultrasonic impact treatment (UIT) on the surface structure, microhardness, and tribological behavior of L-۶۰۵ superalloy. The surface of the samples was impacted by a high-frequency (۲۰ kHz) spherical tungsten carbide tool for one, two, three, and five passes, using a feed rate of ۰.۰۸ mm/min, vibration amplitude of ۲۸ %, and static pressure of ۰.۱ MPa. Results showed that UIT significantly deformed the surface microstructure and enhanced surface microhardness, primarily due to work hardening, strain-induced martensitic transformation, and ultrafine grain formation. A single UIT pass notably improved wear resistance and reduced the friction coefficient. Compared to the annealed alloy, the one-pass UITed samples showed wear rate reductions of ۷۴%, ۷۰%, ۶۸%, and ۶۴% under loads of ۵, ۱۰, ۲۵, and ۷۵ N, respectively. The average friction coefficient also dropped by up to ۸۰% at ۱۰ N and ۷۴% at ۷۵ N. Additional UIT passes resulted in marginal microhardness improvement, likely due to strain hardening saturation in the surface layers.

کلیدواژه ها:

L-۶۰۵ alloy ، ultrasonic impact treatment ، sliding wear ، friction ، tribology