Abstract

Magnesium (Mg) alloy sheets usually suffer from severe mechanical anisotropy and a trade-off between strength and ductility. In this work, the effects of rolling temperature (200 °C and 400 °C) and rolling speed (50–1000 r/min) on the microstructure and mechanical properties of a Mg-1Sm (samarium, Sm) (wt.%) alloy were systematically investigated. Low-temperature rolling (200 °C) results in high dislocation density and a double-peak basal texture in Mg-1Sm alloy, causing very limited plasticity and a pronounced anisotropy with a lower yield strength along the rolling direction (RD) than along the transverse direction (TD). A significantly improved mechanical property (yield strength of ~196 MPa, elongation of 18.4% and near-isotropy) can be achieved in the Mg-1Sm alloy by optimizing the rolling conditions (400 °C, 500 r/min). The findings indicate that increasing the temperature is beneficial for activating non-basal slip and multiple twinning modes, thereby weakening and dispersing the basal texture, which can efficiently improve the anisotropic properties. Increasing the rolling speed can promote the recrystallization process, resulting in the enhancement of plasticity. Quantitative analyses reveal that the reduction in dislocation density and the suppression of Sm segregation at grain boundaries under high-temperature high-speed rolling are responsible for the improved ductility and reduced anisotropy.

IPC Classification

Keywords