Efficacy of laser shock processing of biodegradable Mg and Mg-1Zn alloy on their in vitro corrosion and bacterial response

Laser shock processing (LSP) is increasingly applied as an effective technology for improving the properties of different metallic components. This is done principally to enhance their corrosion and fatigue life behaviour, stress corrosion cracking resistance, etc. In this paper, LSP has been applied to a commercially pure Mg and a Mg-1Zn alloy (wt%) which is aimed to be used as a biodegradable material for biomedical applications. The rational for microalloying with Zn is not only influencing the bacterial response, but also enhancing corrosion resistance and mechanical strength of Mg without causing any toxic effect. The present work is focussed on the examination of the effects of the LSP treatment on the relevant surface related properties of the samples and their correlation with the surface and subsurface induced modifications such as residual stress state, microstructural, roughness, hardness, etc. Central to this investigation is the study of the corrosion response and antibacterial properties against Staphylococcus epidermidis of the different samples as a function of material and LSP parameters. The results show that the application of LSP introduces compressive residual stresses up to 1 mm deep. This occurs together with a significant improvement in corrosion resistance, and less bacterial colonization. [Display omitted] •LSP treatment was successfully applied to extruded pure Mg and Mg1Zn alloy.•Maximum compressive residual stresses, in the range of 20%–25% of their yield strengths, have been achieved by moderate overlapping densities treatments.•Zinc-containing material is more corrosion resistant than pure Mg and the higher EOD promotes higher corrosion resistance at 24 h of immersion in DPBS.•LSP treatment enhances the resistance against bacteria adhesion of alloy and pure magnesium, and is slightly correlated with the density of pulses applied.