Transmission electron microscopy investigations of the microstructures in rapidly solidified Mg-Sn ribbons.

Ribbons of an Mg-9.76 wt.%Sn alloy have been fabricated using rapid solidification technology. X-ray diffraction and transmission electron microscopy confirm that the rapidly solidified ribbons consist of α-Mg, β-Mg2 Sn and β″ -Mg3 Sn phases. The α-Mg grains are refined in the ribbons. The predominant fraction of the β-Mg2 Sn phase distributes at the grain boundaries of the α-Mg grains. The minor fraction of the β-Mg2 Sn phase reveals a spherical morphology with a typical grain size of 170 nm. The orientation relationship between the β″ -Mg3 Sn particles and α -Mg matrix is identified in the ribbons and an atomic structure model of the β″ -Mg3 Sn phase is proposed.