Plastic deformation mechanisms of biomedical Co–Cr–Mo alloy single crystals with hexagonal close-packed structure

Wataru Kaita,Koji Hagihara,Luís Augusto Rocha,Takayoshi Nakano

doi:10.1016/j.scriptamat.2017.08.016

Abstract

This is the first report of the successful fabrication of Co–Cr–Mo biomedical alloy single crystals with a hexagonal close-packed (hcp) structure and the resultant clarification of its deformation behavior. The (0001)〈112¯0〉 basal and {11¯00}〈112¯0〉 prismatic slip systems were found to be predominately operative. The critical resolved shear stresses for the basal and prismatic slip systems at ambient temperature are ~204 and ~272MPa, respectively, which are much higher than ~54MPa for {111}〈112¯〉 slip in the face-centered cubic (fcc) Co–Cr–Mo phase, quantitatively demonstrating that the hcp phase acts as an effective strengthening phase.

Highlights

This is the first report of the successful fabrication of Co–Cr–Mo biomedical alloy single crystals with a hexagonal close-packed structure and the resultant clarification of its deformation behavior
The critical resolved shear stresses for the basal and prismatic slip systems at ambient temperature are ~204 and ~272 MPa, respectively, which are much higher than ~54 MPa for {111}〈112〉 slip in the face-centered cubic Co–Cr–Mo phase, quantitatively demonstrating that the hcp phase acts as an effective strengthening phase
Co–Cr–Mo alloys have been widely applied for surgical implants such as the hip joint and artificial knee joint owing to their high strength, high corrosion resistance, superior wear behavior, and modest biocompatibility [1–3]

Summary

Introduction

This is the first report of the successful fabrication of Co–Cr–Mo biomedical alloy single crystals with a hexagonal close-packed (hcp) structure and the resultant clarification of its deformation behavior. We recently conducted a study with a γ(fcc)phase single crystal and clarified the strong orientation and microstructural dependence of the plastic deformation behavior [14].

Results

Conclusion