Investigation of the microstructures and mechanical properties of the Mg-(2, 5, 8) wt.%sn alloys at high temperatures after an ECAE process

This study focused on the effect of tin content on the microstructures and mechanical properties at high temperatures after Equal Channel Angular Extrusion (ECAE). The results showed that the Mg ₂Sn phase increased gradually with the addition of tin. The grain boundary of the Mg-Sn alloys was seen to contain continuous eutectic α-Mg+Mg ₂Sn precipitates in the Mg-5(wt.%)Sn and Mg-8(wt.%)Sn as-cast alloys. Besides the grain boundary particles, ultra fine Mg ₂Sn particles were exhibited within the matrix of the alloy. After ECAE process, the effect of grain refining was very obvious and the continuous eutectic α-Mg+Mg ₂Sn were broken by ECAE. Optimum mechanical properties were attained by adding 5(wt.%)Sn. The UTS increased from 67 MPa to 179 MPa at 200 °C and from 103 MPa to 248 MPa at 100 °C as well as the elongation increased from 10.6% to 18.9% at 200 °C and from 9.7% to 14.5% at 100 °C after four ECAE passes.