Effect of heat treatment on mechanical properties of Mg-10.02Li-3.86Zn-2.54Al-1.76Cu alloy

Effect of heat treatment on mechanical properties of super-light Mg-10.02Li-3.86Zn-2.54Al-1.76Cu alloy were investigated. Results show that the solution of Mg and Al in solid β phase, the hardness of the alloy is increased, the Mg-Li alloy has been softened, due to precipitation of a and AlLi from β phase during the aging process after quenching at 350°C, and the higher aging temperature accelerates the softening process. Meanwhile, the alloy's strength was increased due to solution increasing when the quenching temperature is reached to 250°C. However, a higher quenching temperature of 350°C results in the alloy's grain coarsening; a phase precipitates easily along β grains, due to super-saturation of Mg in β phase as quenched at 350°C. As a result, the tensile strength and ductility of the Mg-Li alloy were decreased largely.