Cold-working mediated converse age hardening responses in extruded Mg-14Gd-2Ag-0.5Zr alloy with different microstructure

Figuring out the influencing factors is important to explore the potential of age hardening response for Mg alloys. Here the effect of different microstructure on age hardening response in extruded Mg-14Gd-2Ag-0.5Zr alloy is investigated. The age hardening response is weakened by cold-rolling for the extruded sample with large grain size due to the solute atom segregation to form bulk particles in twin boundaries during aging. Conversely, the age hardening response is enhanced by cold-rolling for the extruded sample with fine grain size and dynamical precipitates along grain boundaries, which is attributed to the segregation of solute atoms into the nano subgrain boundaries within grains during aging.