Microstructure and mechanical properties of Mg–Al–Sn extruded alloys

Abstract Mg–Al–Sn alloys are being developed as a new series of magnesium alloys due to their good creep resistance, ductility and high temperature properties. The Mg–Al–Sn alloys containing low Al/Sn-content may have potential as a high-ductility wrought magnesium alloy. However, the effect of composition on the microstructure and mechanical properties of wrought Mg–xAl–ySn alloys have received little attention. In the present work, Mg–xAl–ySn–0.3Mn (x = 1, 3, 6 and y = 1, 3) alloys have been prepared by hot extrusion at temperatures from 523 K to 623 K. The experimental results reveal that the yield strength of the as-extruded alloys is sensitive to Al content and extrusion temperature, but insensitive to Sn content. The yield strength increases with decrease Al content or extrusion temperatures. The Mg–1Al–ySn–0.3Mn (y = 1, 3) alloys extruded at the temperatures ≤573 K exhibit the relative higher yield strength in this paper (the yield strength exceed 250 MPa with elongation of about 20%). The relative high strength is mainly attributed to the formation of fine recrystallized grains and high fraction of coarse un-recrystallized grain regions which show strong (10-10) and (0001) textures. The orientation relationship between the precipitated Al 8 Mn 5 phase and the Mg matrix in the Mg–1Al–1Sn–0.3Mn alloy is also determined. And the strengthening mechanism of the alloys is discussed.