The quantitative regulation of basal and prismatic Mg2Sn to strengthen Mg-Sn alloys

Abstract

The continuous network of prismatic and basal precipitates in Magnesium (Mg) based alloys can improve the strength to the largest extent, even better than the prismatic one. This work constructed basal-prismatic Mg2Sn phases in varying proportions to investigate the impact of different proportions of basal or prismatic phases on the mechanical properties of Mg-5 wt% Sn alloy. The finding revealed that a combined process of twinning, first aging, de-twinning and second aging (T-A1-DT-A2) can generate dual-precipitates in both basal and prismatic planes in the interior of the same grain regions. By regulating the first and second aging procedures, it is possible to acquire specific proportional basal or prismatic Mg2Sn in Mg-Sn alloys. The strength and toughness of Mg-Sn alloy containing dual-precipitates in both basal and prismatic planes are simultaneously enhanced. Especially, the tensile and compressive yield strength (TYS and CYS), tensile and compressive ultimate strength (UTS and UCS) of Mg-Sn alloy with basal-prismatic Mg2Sn can reach 217 MPa, 163 MPa, 318 MPa and 441 MPa, compared to the sample with basal phase, which is improved by 149.4 %, 108.9 %, 82.7 % and 50.5 %, respectively. The sample with the sample first and second aging time (T-A15-DT-A15) shows more excellent comprehensive mechanical properties at room temperature. High strength might be attributed to the dislocation strengthening (26 MPa), fine grain strengthening (4.5 MPa) and precipitate orientation strengthening (102 MPa).