Rapid dislocation-mediated solute repartitioning towards strain-aging hardening in a fine-grained dilute magnesium alloy

Achieving appreciable strain-aging hardening coupling with fine-grain strengthening remains a critical challenge in dilute Mg alloys, as high-temperature solid-solution, utilized to impart high-level solutes for strain-aging, inevitably causes grain coarsening and great strength loss. Herein, we report a rapid dislocation-mediated solute repartitioning behavior upon aging in a low-temperature annealed Mg-1.0Zn-0.45Ca-0.33Sn-0.2Mn (wt.%) alloy. Thereby, appreciable strain-aging hardening (YS increment of similar to 30 MPa) coupling with fine-grain (grain size of similar to 2.5 mu m) strengthening accounts for a high yield strength (similar to 297 MPa) and ductility (similar to 20%). It suggests a feasible avenue to develop strong dilute Mg alloys by combining strain-aging hardening and fine-grain strengthening. IMPACT STATEMENT By manipulating solute distribution while keeping a fine-grain structure, appreciable strain-aging hardening response coupling with fine-grain strengthening guarantees the development of strong dilute Mg alloy.