Alloy Design for the Development of Heat Treatable High Strength Mg Sheet Alloy with Excellent Room Temperature Formability

Abstract

To widen the application of the magnesium sheet alloys, good room temperature (RT) formability and satisfactory strength need to be achieved. The development of heat treatable alloy can be an effective approach to simultaneously achieve the good RT formability and satisfactory strength. In this work, we have investigated the effects of Zn content on the microstructure, stretch formability and mechanical properties in the Mg–xZn–0.36Zr–0.32Ca (x = 3, 4, 5 wt%) sheet alloys. The as-rolled samples showed strong basal textures regardless of the Zn content. However, the decrease in the Zn content resulted in the significant texture weakening in the solution treated samples, and this leads to the improvement of the stretch formability up to 7.3 mm in Index Erichsen value in the Mg–3.1Zn–0.36Zr–0.32Ca alloy. Subsequent artificial aging at 160 °C for 16 h slightly increased the tensile yield strength of Mg–4Zn–0.36Zr–0.32Ca alloy sheet from 176 to 194 MPa. This work has demonstrated that the Mg–Zn system is promising to achieve excellent RT formability and high strength, however, the slow age hardening kinetics needs to be improved to make it industrially viable.