Microstructure characterization and indentation hardness testing behavior of Mg-8Sn-xAl-1Zn alloys

Abstract

The influence of Al content on microstructure characterization and indentation hardness testing behavior of Mg-8Sn-xAl(x=1 wt%, 2 wt%, 3 wt%)-1Zn alloys was investigated by optical microscope, Pandat software, X-ray diffraction, scanning electron microscope, differential scanning calorimetry and a microhardness testing equipment. The results can be summarized as follows: when the Al content is 1 wt%, the alloy is composed of α-Mg and Mg2Sn phases; while the new phase of Mgx(AlZn)1-x can be observed and the morphology of Mg2Sn phase transfers from the semi-continuous network to the dispersed particles with further addition of Al content to 2 wt% and 3 wt%. The dendrite arm spacing (DAS) deceases firstly and then slightly increases with the increase of Al content. The micro-hardness of Mg-8Sn-xAl(x=1 wt%, 2 wt%, 3 wt%)-1Zn also increases with increasing of Al content. Moreover, the indentation size effect (ISE) in Vickers hardness for Mg-8Sn-1Al-1Zn alloy was observed with the applied test load ranging from 0.490 to 4.903 N.