Generalized solid strengthening rule for biocompatible Zn-based alloys: a comparison with Mg-based alloys

Solid solution strengthening has been widely used in designing various high-performance biocompatible Mg-based alloys, but its transferability for other biocompatible metals such as Zn-based alloys is questionable while nearly absent. In the present study, an ab initio informed Peierls-Nabarro model and Leyson et al.’s strengthening model is used for a systematic investigation on solute strengthening in Zn-based alloys, which is compared with the widely studied Mg-based alloys. Although an inverse relationship is revealed between volume misfit eb and chemical misfit eSFE for both Zn-based and Mg-based alloys, most solutes would however result in positive eb and negative eSFE for Zn-based alloys, differing from Mg-based alloys. With eb and eSFE as two key descriptors, a generalized scaling diagram is finally drawn for a fast evaluation of solid solution strengthening in Zn-based alloys, indicating that alkaline-earth and rare earth elements are better strengtheners for Zn-based alloys, which provide a general rule in designing novel biocompatible materials.