Process mechanics and surface integrity by high-speed dry milling of biodegradable magnesium-calcium implant alloys

Compared to conventional metallic implant materials, biodegradable Mg-Ca alloys are attractive orthopedic biomaterials that avoid negative stress shielding and revision surgeries. However, the process mechanics and surface integrity by high-speed dry milling Mg-Ca0.8 are poorly understood. Key findings of the synergistic experimental and numerical study are: (a) Mg-Ca0.8 alloy is sensitive to strain rate and adiabatic softening; (b) high-speed dry milling can be safely performed using PCD tools with process characteristics of lamella structured chips and slight flank build-up; and (c) machined surface integrity is characterized by low roughness, highly compressive residual stress, increased microhardness, and microstructure without phase changes.