Development of a Low-Cost and Room-Temperature Formable Mg Alloy Sheet with In-Plane Isotropic Tensile Properties

Abstract

Twin-roll-cast Mg-3.07Al-0.25Mn (mass%) alloy was continuously rolled at a warm temperature, and the room-temperature stretch formability, tensile properties, microstructures, and texture of the annealed sheets were investigated. The sheet rolled at 220 °C exhibits large Index Erichsen values over 8 mm due to the formation of a ring-like texture feature where the basal poles are oriented ~25° from normal direction to all directions. Fine grain structure with an average grain size of ~7 µm could be obtained, so that the sheet shows moderate 0.2% proof stress of ~160 MPa and large elongation to failure over 25% in both rolling and transverse directions. The fabrication process of the alloy sheet, which consists of homogenization, warm-temperature rolling, and annealing, is viable in industrial production and accordingly, the alloy sheet developed in this work will broaden the commercial applications of wrought Mg alloys in automotive industries.