Rolling Contact Fatigue Behaviors of C17200 Beryllium-Copper Alloy Processed by Surface Mechanical Rolling Treatment

Under severe work conditions, mechanical parts made of beryllium-copper alloy may undergo fatigue failure, which seriously affects the overall service life of the equipment. Therefore, improving the fatigue resistance of such kind of alloys is of great significance for their engineering application. In this research, C17200 beryllium-copper alloy was surface strengthened by means of a self-designed surface mechanical rolling treatment (SMRT) device. The fatigue behavior before and after SMRT was investigated using a ball-on-rod rolling contact fatigue (RCF) machine, and surface failure mechanisms were analyzed. It was found that the RCF resistance of the untreated C17200 alloy was weakened with the increase in the maximum Hertzian contact stress (σ_max). After surface treatment, C17200 alloy exhibited superior RCF resistance subjected to SMRT with a static rolling force of 200 N. But among the specimens treated by SMRT, the RCF resistance of beryllium-copper alloys was weakened with the increase in the SMRT static rolling force. The RCF life of specimens treated by SMRT with a force of 400 N is similar to that of untreated specimens, while the RCF lives of specimens treated by SMRT with a force of 735 and 980 N are even lower than that of untreated specimens. Thus, applying the appropriate static rolling force during SMRT can improve the surface quality and compressive residual stress, as well as enhance the fatigue resistance of C17200 alloys.