The influence of Ca and Gd microalloying on microstructure and mechanical property of hot-rolled Mg-3Al alloy

摘要

After hot rolling magnesium alloy sheets exhibit an intensive basal texture, leading to its low formability at room temperature. Microalloying is an effective, practicable and economical measure to improve the comprehensive performance of magnesium alloy, especially for taking Ca and Gd as main components recently which greatly increases the room temperature formability of magnesium alloy by attenuating or tilting the basal texture. In this study some Mg-3Al alloys with Ca single and Ca-Gd combined microalloying were hot rolled at 673K and annealed at 623K for 1h. The effect of addition of Ca and Gd on microstructure, texture and tensile properties of Mg-3Al series alloy were investigated. The results showed that the single addition of Ca element can attenuate basal texture and improve room temperature formability of Mg-3Al alloy, but limitedly refine grain size. The combined addition of microalloying Ca and Gd element can significantly attenuate basal texture and improve refinement of grain size and room temperature formability of Mg-3Al alloy, also reduce the anisotropy of mechanical property. The main reason for attenuating basal texture is that the recrystallization behavior is delayed due to the secondary phase. The attenuating of basal texture and the activation of non-basal slip systems are the mechanism of the reduced anisotropy.