Experimental Study of the Mechanical Properties at Elevated Temperatures in Commercial Mg-Al-Zn Alloys for Superplastic Forming

摘要

The mechanical properties in two commercialMg-Al-Zn alloys were investigated at elevated temperatures.The alloys were examined for tensile tests and thencharacterized. The deformation mechanism in two alloys variedwith their grain sizes. A coarse-grained (>100 #mu#m) alloyexhibited a strain rate sensitivity of ~0.33, and fractured withsignificant development of necking. On the other hand, finer-grained alloys with grain sizes less than 20 #mu#m exhibited ahigh strain rate sensitivity ~0.5, and failed with brittle fracturecorresponding to the cavity growth. The grain size dependenceon the tensile properties was discussed to apply these alloys forsuperplastic forming.