Enhanced age-hardening in a lean Mg-Al-Ca-Mn alloy by trace silver addition

Promoting the precipitation of Guinier-Preston (G.P.) zones in fast-extruded Mg-Al-Ca-Mn alloys could enhance the age-hardenability, which remains a significant challenge. Herein, we report an unexpected enhancement of age-hardenability in a Mg-0.35Al-0.13Ca-0.18Mn alloy (at.%) by a mere addition of 0.02 at.% Ag, i.e. the hardening response increases from 38 MPa to 59 MPa. The Ag addition is demonstrated to promote the early-stage solute clustering, which is responsible for the promoted precipitation of G.P. zones with a denser distribution. Our findings may provide new insights into the development of fast-extruded Mg-Al-Ca-Mn alloys with high strength.