Effect of Nitrogen Ion Implantation on the Cavitation Erosion Resistance and Cobalt-Based Solid Solution Phase Transformations of HIPed Stellite 6

From the wide range of engineering materials traditional Stellite 6 (cobalt alloy) exhibits excellent resistance to cavitation erosion (CE). Nonetheless, influence ion implantation cobalt alloys on CE behaviour has not been completely clarified by literature. Thus, this work investigates effect nitrogen (NII) HIPed improvement CE. Finally, cobalt-rich matrix phase transformations due both NII and load were studied. The stellites ion-implanted 120 keV N+ ions two fluences: 5 × 1016 cm−2 1 1017 comparatively analysed with unimplanted stellite AISI 304 stainless steel. tests conducted according ASTM G32 stationary specimen method. Erosion rate curves mean depth confirm that nitrogen-implanted times exceeds than stellite, almost ten higher reference X-ray diffraction (XRD) confirms favours transformation ε(hcp) γ(fcc) structure. Unimplanted ε-rich is less prone plastic deformation γ consequently, increase effectively holds carbides in prevents Cr7C3 debonding. This phenomenon elongates three incubation stage, slows mitigates material loss. Metastable structure formed consumes for work-hardening → ε martensitic transformation. In further stages, phases transform as alloy namely, cavitation-inducted recovery process, removal strain, dislocations resulting phase. mechanism was investigated using a surface profilometer, atomic force microscopy, SEM-EDS XRD. wear relies matrix, starting at Cr7C3/matrix interfaces. Once particles lose from restrain, they debond are removed material. Carbides detachment creates pits which initiate cracks propagation through leads loss result proceeds massive chunk materials.