Martensitic transformation behavior during tensile testing at room temperature in β-type Mg-35 wt%Sc alloy

Abstract

The β-type Mg-Sc alloys have attracted considerable attention from researchers due to their martensitic transformation behavior. However, the relatively low martensitic transformation temperature limits their practical application. In this paper, the α- and β-type Mg-35 wt%Sc alloy sheets with the thickness of 2 mm were prepared by quenching. The stress-induced martensitic transformation was detected in the β-type alloy during tensile testing at room temperature, while no phase transformation occurred in the fractured α-type alloy. The stress-induced martensite was confirmed to have an hcp-based structure. Both the lath and lenticular martensites were observed in the fractured β-type alloy. The substructure of lath martensite was presented by the high-density dislocations, while that of lenticular martensite contained twins and dislocations. In addition, the reason for the occurrence of the bcc-to-hcp martensitic transformation in β-type Mg-35 wt%Sc was discussed. The research on the bcc-to-hcp martensitic transformation at room temperature is of great significance to overcome the strength-ductility trade-off in Mg alloys.