Microstructural characterisation of subsurface deformation and the degradation of Stellite 6 induced by self-mated sliding contact in a simulated PWR environment

Stellite 6 (Co-29.5%Cr-5%W-1.2%C in wt%) is traditionally used as a hardfacing material the primary circuit of pressurised water reactors (PWRs) due to its good corrosion and wear resistance at up 300 °C. In this study, pin-on-disc type sliding contact tribocorrosion testing was conducted on HIPed 20 °C 250 using bespoke tribometer simulate environment. Transmission electron microscopy (TEM), scanning (SEM), X-ray diffraction (XRD) were characterize, for first time, affected by tribocorrosion. Whilst loss increases 16–39 times when test temperature increased from °C, mechanisms degradation deformation remain largely unchanged. Furthest contact, strain principally accommodated deformation-induced transformation ? Co-based matrix ?-martensite. Closer ?-martensite phase accommodates further via twinning dislocation slip. At intense generates nanocrystalline structure. The tribologically resistant plastic localisation; confines nanoscale where synergistic effects chemical mechanical permit removal particulates (corrosion enhanced nanowear (tribocorrosion)). rate attributed dependent increase nanowear. revealed are important design future hardfacings.