Microstructure and mechanical properties of Mg–6Li–xAl–0.8Sn alloys

Abstract

As-cast and as-extruded Mg–6Li– xAl–0.8Sn ( x = 0, 1, 3 and 5 wt-%) alloys were prepared. The microstructure and mechanical properties were investigated and discussed. The experimental results show that the Mg–6Li–0.8Sn alloy is composed of three phases: α-Mg, Mg2Sn and Li2MgSn. With the addition of Al, the test alloys display typical α-Mg + β-Li duplex structures. The new Mg17Al12 and LiMgAl2 phases were found in the Mg–6Li–1Al–0.8Sn alloy. The lamellar-type AlLi phase was formed whereas the Mg17Al12 phase disappeared in Mg–6Li–3Al–0.8Sn alloy. The LiMgAl2 phase vanished in the Mg–6Li–5Al–0.8Sn alloy. The mechanical properties of as-extruded alloys were remarkably improved. The as-extruded Mg–6Li–3Al–0.8Sn alloy exhibited the best mechanical properties, with a yield strength, tensile strength and elongation of 209.8 MPa, 242.6 MPa and 15.5%, respectively.

Intermediate-Temperature Tensile Behavior of a Hot-Rolled Mg-Li-Al-Cd-Zn Alloy

“…As the lightest structural metal material, Mg-Li alloys are expected to be widely used in the aerospace, health care, automobile and electronic industries because of their low density, high specific strength and elastic modulus, excellent formability and damping property [ 1 , 2 , 3 , 4 ]. However, the relatively low strength, poor corrosion resistance and limited thermal stability of binary Mg-Li alloys severely hinder their practical applications [ 5 , 6 ]. It is well documented that Mg-Li alloys with a hexagonal closed-packing structure phase (hcp-α) have a moderate strength and a limited formability, while the body-centered cubic structure phase (bcc-β) Mg-Li alloy demonstrates an excellent workability but notably lower strength [ 7 , 8 ].…”