Shanghai Wei

Study on microstructure and mechanical properties of as-cast Mg-Sn-Nd alloys

Abstract Microstructure, tensile properties and compressive creep behaviors of Mg-(1.65–11.52) wt.% Sn-2 wt.% Nd alloys were studied in this paper. The microstructure of the as-cast Mg-Sn-Nd alloys consisted of dendritic α-Mg, Mg 2 Sn and Mg-Sn-Nd ternary phase containing rare earth element. The highest ultimate tensile strength of 140 MPa and percentage elongation after fracture of 9.7%, were achieved with a composition of Mg-8.23 wt.% Sn-2 wt.% Nd. The compressive creep resistance of Mg-8.23 wt.%Sn-2 wt.% Nd alloy was much better than other alloys at 200 °C for applied load of 35 MPa, which was mainly due to the formation of dispersive heat-resistance Mg 2 Sn and Mg-Sn-Nd intermetallic compounds.

Microstructure, tensile properties and compressive creep resistance of Mg-(5–8.5)%Sn-2%La alloys

Abstract The microstructure, tensile properties and compressive creep resistance of permanent-mould cast Mg-(5–8.5)%Sn-2%La (mass fraction) alloys were investigated. The results show that Mg-(5–8.5)%Sn-2%La alloys are all composed of α -Mg phase, Mg 2 Sn and Mg-La-Sn compounds. Compared with those of Mg-5%Sn binary alloy, the grain size and the content of Mg 2 Sn compound in Mg-5%Sn-2%La alloy are decreased. With the increase of Sn content in Mg-(5–8.5)%Sn-2%La alloys, the content of Mg 2 Sn compound increases, while that of Mg-Sn-La compound changes little. In addition, the investigation suggests that the thermally stable Mg-Sn-La and Mg 2 Sn compounds can improve the tensile properties and compressive creep resistance of the alloys.

Compressive creep behavior of Mg-Sn binary alloy

Mg-Sn based alloy is one of the potential alloys for application at elevated temperature. The compressive creep behavior of ageing-treated Mg-χSn (χ=3%, 5%) alloys was investigated at the temperatures of 423 and 473 K and the stresses from 25MPa to 35MPa. When the tin content varies, the ageing-treated Mg-χSn alloys show quite different creep resistance, which are mainly attributed to the size and distribution of Mg2Sn phases in the ageing-treated Mg-χSn alloys. The calculated value of stress exponent, n=6.3, suggests that the compressive creep behavior of the ageing-treated Mg-5%Sn alloy is controlled by dislocation creep at the temperature of 473 K and the stresses from 25MPa to 35MPa.