Enhanced mechanical properties of α-phase LA51 alloy using caliber rolling

Abstract

This study investigates the microstructural evolution and mechanical properties of the Mg–5Li–1Al (LA51, wt.%) alloy, aimed at developing a high strength single-phase Mg–Li alloy. The alloy was successfully produced using caliber rolling (CR) with varying rolling reductions (i.e., 38 %, 65 %, 80 %). The results indicate that CR effectively reduces the grain size from ∼68.5 μm to ∼8.1 μm. The primary mechanisms of grain refinement include continuous dynamic recrystallization (CDRX), discontinuous dynamic recrystallization (DDRX), and twin-induced recrystallization (TDRX). With an increase in rolling reduction to 80 %, the tensile yield strength (TYS), ultimate tensile strength (UTS), and elongation (El.) of the LA51 alloy reach 265.7 MPa, 324.2 MPa, and 11.9 %, respectively. Furthermore, CR significantly enhances the tensile-compressive asymmetry of LA51 alloy as well. The improved mechanical properties of such alloy are attributed to grain refinement and dislocation strengthening mechanisms.

Keywords

• Mg–Li alloy
• Caliber rolling
• Microstructure
• Mechanical properties