Effects of Al and Zn additions on mechanical properties and precipitation behaviors of Mg–Sn alloy system

Abstract For the Mg–Sn–Al alloys, the ultimate strength (UTS) of an extruded Mg–9wt.%Al–2wt.%Sn alloy reached 390 MPa. TEM observation indicated that plate-like Mg 17 Al 12 precipitates having Burgers orientation relationship with the matrix are responsible for the strength. This alloy also exhibits an age hardening behavior: the peak hardness appears after 15–20 h of heat treatment at 473 K. On the other hand, the UTS of the Mg–Mg–Sn–Zn alloys are on the order of 300 MPa. The precipitates in these alloys are composed of the Mg 2 Sn and MgZn 2 particles. It was found that these phases often precipitate together, suggesting that the MgZn 2 phase can act as a nucleation sites for Mg 2 Sn.