Effect of minor Sr on precipitates in AZ31 magnesium alloys

Minor Sr can effectively improve the mechanical properties such as yield strength, ultimate tensile strength and elongation of AZ31 magnesium alloys. In the present work the authors try to explain the mechanisms from the effect of minor Sr on the precipitates in AZ31 magnesium alloys. The research results indicate that 0.25% Sr addition has obvious influence on the precipitates both in the as cast and as extruded AZ31 alloys, resulting in the improvement of the mechanical properties. For the as cast AZ31 magnesium alloys, after Sr addition the precipitates were refined and Al4Sr phase formed, while for the as extruded AZ31 magnesium alloys the Sr addition was found to refine both the micrometre sized and nanometre sized precipitates, and also helping their solution during hot extruding.