Solute and Temperature Effects on the Strain Hardening Behaviour of Mg-Zn Solid Solutions

The Kocks-Mecking method of analysis is applied to solid solutions of up to 2.6 at.% Zn to separate the contributions to the alloys’ strain hardening rate from dislocations storage, solute in solution, and twinning, for temperatures between -50 ºC (273 K) and 200 ºC (473 K). Athermal storage of dislocations seems to account for the largest share of the strain hardening rate for both the pure metal and the solid solutions at or below room temperature. Solute in solution does not increase the strain hardening rate over that of pure Mg, although it delays the onset of dynamic recovery, especially for the higher alloys, presumably due to short range order. Twinning remains a very important deformation mechanism for the pure metal and the dilute alloys up to 200 ºC.