Significant improvement of corrosion resistance of biodegradable metallic implants processed by laser shock peening

Biodegradable magnesium–calcium alloys are attractive new orthopedic biomaterials compared to conventional permanent implant alloys. However, magnesium–calcium alloys corrode too fast in human body fluids. This study explores the process capability of laser shock peening (LSP) to control the corrosion of magnesium–calcium implants by tailoring the surface integrity. LSP induced unique surface topographies, highly compressive residual stresses, and extended strain hardening significantly enhanced the corrosion resistance of the alloy by more than 100-fold in simulated body fluid. Furthermore, corrosion of the peened implants was controllable by varying the laser power and peening overlap ratio.