fig2

Figure 2. Low and high magnification BSE-SEM images of (A and C) Mg_1.95Si_0.3Sn_0.7, (B and D) Mg_1.95Si_0.233Sn_0.7Sb_0.067. The BSE-SEM images show the microstructure of undoped and doped Mg-poor material. One can see that globular, sub-structured inclusions are visible in both samples. Those inclusions are Si-rich Mg₂X precipitated. Some contrast is also visible in both matrixes. Similar contrast is also visible in Mg-rich material as shown in Figure 2. Such contrast is due to slight Si:Sn variations. EDS mapping of the Si-rich regions are given in Supplementary Figure 2. EDS: Energy dispersive X-ray spectroscopy; BSE-SEM: backscattered electron-scanning electron spectroscopy.