The response of mechanical property to the microstructure variation of an Al–Mg alloy by adding tin element

Abstract In this work, the microstructural evolution and mechanical behavior of as-cast Al–5Mg alloys with various tin (Sn) contents were investigated. Combined with microstructure characterization and mechanical property test, the refinement of α-Al grains, the composition of phases containing Sn, and the change in tensile property of alloys caused by adding Sn element were discussed. It was demonstrated that Sn could react with magnesium (Mg) to form Mg2Sn phases in the Al–5Mg alloys as the Sn content increased from 0.05 wt% to 1.00 wt%. When the Sn element content was 0.30 wt%, a considerable refinement of α-Al grains and an obvious improvement in tensile property of the Al–5Mg–0.30Sn alloy were obtained. The tensile strength and elongation of the Al–5Mg–0.30Sn alloy were 210.8 MPa and 25.9%, respectively. The strengthening-toughening mechanism associated with Mg2Sn phases was revealed. Nano-sized and deformable Mg2Sn phases could result in the second phase strengthening and crack propagation inhibition effects.