Atomic simulations of nanoscale friction behavior in polycrystalline alloy 690

Abstract Fretting wear is one of the most important failure forms of alloy 690 heat exchanger tubes in nuclear power plants. The key to understanding the fretting wear of alloys lies in the friction process, especially at the atomic scale. In this study, molecular dynamics simulations were performed on alloy 690 to investigate the nanoscale friction behavior and its influencing factors, laying a foundation for further understanding the fretting wear mechanism of alloy 690. The friction processes of a single-asperity (probe) on a smooth polycrystalline surface (matrix) were investigated by molecular dynamics simulations at the atomic scale, and the variation law of friction force during the friction process was calculated. The factors that affected the friction force were discussed, including the pressing depth, temperature, and sliding speed of the probe, and the friction force was positively correlated with the pressing depth and sliding speed of the probe, while the temperature had little effect on the friction force. Observations of the generation and evolution of dislocations during the friction process and related factors such as grinding grooves and wear debris were also reported.