Evolution of fretting wear behavior of zirconium alloy cladding tube under gross slip regime in simulated primary water of pressurized water reactor

The evolution of fretting wear behavior of zirconium alloy cladding tubes mated with dimples under the gross slip regime (GSR) was investigated. The findings revealed that the primary wear mechanisms under GSR were delamination, surface fatigue wear and abrasive wear, and the fretting damage rate mainly depends on delamination. The cross-sectional microstructure of the worn area could be divided into the third-body layer, tribologically transformed structure layer, and general deformation layer, with their formation mechanisms analyzed. Furthermore, the mechanism of wear-induced grain refinement was identified as dynamic recrystallization (DRX), including both continuous DRX and discontinuous DRX. Additionally, the processes of fretting wear and DRX were discussed.