Strain burst in creep of Mg–1Ca–0.5Zn–0.6Zr alloy

The creep behaviour and tensile properties of Mg–1Ca–0.5Zn–0.6Zr (wt.%) alloy have been studied. The alloy exhibited periodical strain bursts during creep testing at 150 °C in the peak-aged condition, while over-ageing treatment tended to eliminate the occurrence of strain burst. The strain burst was ascribed to the dynamic strain ageing (DSA) effect from the interaction between dislocations and solute atoms, which was supported by the serrated flow, yield points after static ageing, and negative strain rate sensitivity observed in tensile tests over a temperature range 150–200 °C. The high values of stress exponent of creep were interpreted in terms of breakaway of dislocations from the solute atmospheres.