A 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 to other biocompatible metals such as Zn-based alloys is questionable or nearly absent. In the present study, an ab initio informed Peierls-Nabarro model and Leyson et al.'s strengthening model are 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 was revealed between volume misfit epsilon (b) and chemical misfit epsilon (SFE) for both Zn-based and Mg-based alloys, most solutes would however result in positive epsilon (b) and negative epsilon (SFE) for Zn-based alloys, differing from Mg-based alloys. With epsilon (b) and epsilon (SFE) 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 the alkaline-earth and rare earth elements are better strengtheners for Zn-based alloys, which provides a general rule in designing novel biocompatible materials.