Effect of surface mechanical attrition treatment on the microstructure of cobalt–chromium–molybdenum biomedical alloy

Abstract This research work describes the impact of the surface mechanical attrition treatment (SMAT) on the microstructure of cobalt–chromium–molybdenum (CoCrMo), a biomedical alloy commonly used for orthopedic applications. This surface treatment induces crystalline phases transformations characterized by X‐ray diffraction (XRD) and selected area electron diffraction (SAED). The corresponding structural changes are observed from cross‐section images obtained by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that the SMAT process induces the martensitic transformation of the CoCrMo alloy (from γ‐fcc phase to ε‐hcp phase) related to an important grain refinement due to twinning and sliding.