Effect of quenching temperature on microstructure and mechanical properties of Mg-35 wt%Sc alloy

In this work, the microstructure, microhardness and compressive mechanical properties of quenched Mg -35 wt%Sc alloy at 540 degrees C, 600 degrees C, and 630 degrees C were investigated. The microstructure of three specimen is mainly composed of alpha and beta phases. With an increase in the quenching temperature, the fraction of beta-phase is increased, indicating that the phase transformation occurs from alpha to beta phase. On the other hand, the grain size of alpha-phase is reduced and the morphology of beta-phase changes from needle-like to bulk structure. In addition, the texture intensity of beta-phase is significant decreased, which suggests that the quenched alloy at 630 degrees C has a relatively random beta texture. Among them, the specimen quenched at 630 degrees C exhibits the highest Vicker's hardness of 113.3 +/- 1 HV and ultimate compressive strength (UCS) of 551 +/- 5 MPa, which is attributed to the solid solution strengthening effect of Sc and fine-grained strengthening of alpha-phase. Moreover, with the increase of beta-phase in alloy, the plasticity is also increased from 26.8 +/- 0.8% to 31.7 +/- 0.9%. These researches on bcc-type Mg-Sc alloy provide a novel strategy for future structural magnesium alloy design.(c) 2023 Elsevier B.V. All rights reserved.