Effect of heat-treatment on microstructure, mechanical and tribological properties of Mg-Li-Al based alloy

Abstract

In the present study, the microstructure evolution and mechanical properties of as-cast Mg-9 wt.%Li-7 wt.%Al-1 wt.%Sn (LAT971) alloy during solid solution treatment are investigated. Further, the age softening of solid solution treated alloys is analyzed at 50 °C and 100 °C from 0.5 h to 5 h. The hardness of the α- and β-phase of LAT971 alloy is observed to increase by ∼61% and ∼136%, respectively after solutionizing, when compared to that of as-cast condition. Further, the hardness of both the phases has decreased after aging treatment due to age-softening effect. Additionally, finite element modeling (FEM) is used to elicit the effects of microstructural changes on stress distribution of thermally treated LAT971. In addition, the solutionized condition has educed higher wear resistance than as-cast condition of LAT971 alloy. The higher scratch hardness (∼1.35 and ∼1.74 times for α- and β-phase, respectively) resulted in the lower wear volume, and, subsequently, lower specific wear rate is obtained for solutionized alloy when compared to that of as-cast condition.

Keywords

• Mg-Li-Al alloy
• Heat treatment
• Age softening
• Finite element modeling
• Wear