“Magnesium alloys - Deformation induced clustering and precipitation and their use as biodegradable implant materials”
Recent studies have shed new light onto the mechanisms that control deformation induced solute clustering and precipitation in Aluminum and Magnesium Alloys. Here, we review our collaborative study of deformation-induced clustering and precipitation in simple binary alloys: Mg-9Al and Mg-5Zn (wt.%) alloys following equal channel angular extrusion at 150°C. We leverage TEM studies and analytical models to describe the importance of dislocations in precipitation, and we use atom probe tomography and hybrid molecular dynamics/Monte Carlo simulations to reveal the thermodynamic role of vacancies and vacancy clusters in forming Al and Zn solute clusters. This combination of experiments and computations demonstrates that strategic control of atomic-scale defects can generate novel, far from equilibrium, microstructures, thereby providing an innovative approach to strengthening Mg alloys. The second half of the seminar will focus on our efforts to develop biodegradable implants using Mg alloys with low solute concentrations. After a brief review of Mg’s biocompatibility/bioactivity and clinical performance, I will describe our fabrication of porous scaffolds by 3D weaving with Mg wires. These scaffolds are being optimized for use in healing bone defects, and I will describe their architecture, corrosion rates, and vascularization using a combination of in vitro and in vivo studies. Additional applications under exploration will also be noted.