Abstract
Effect of microstructure on mechanical properties and thermal stability of high strength flame resistance magnesium alloy were investigated. In this present study, we used Mg-Al-Ca (Ca=1 mass%) cast alloys by antigravity cast process with rapid cooling. Sheet of this alloy subjected to a multi-pass rolling process at 300℃ showed a yield stress and ultimate tensile strength were 340 MPa and UTS 350 MPa, respectively. During the multi-passes rolling process, grain refinement occurred as a result of dynamic recrystallization of the Mg phase and dynamic crushing of Al-Ca compounds. Rolled flame resistance magnesium alloy was formed of non-recrystallized grain region was elongated to rolling direction with shear deformation. After annealing treatment, the grain growth was showed 3 to 5 μm at 400℃ for 1 hr because Al-Ca compound fine dispersion in Mg phase and the Al-Ca compound controlled grain growth at high annealing temperature. The thermal stability of this alloy was improved by addition Ca element.
