The Microstructures of As-Cast Mg-Zr and Mg-Mn Alloys
The as-cast microstructures of two dilute Mg-Zr and three dilute Mg-Mn alloys were studied using optical microscopy and scanning electron microscopy, including EDX analysis. The results show that the as-cast microstructure of the Mg-Zr alloys was composed of non-dendritic, equiaxed Mg grains, with a few Zr particles within the Mg grains and along grain boundaries. The grain size of the Mg-Zr alloy was significantly reduced by the Zr addition and a fine grain structure was achieved when the zirconium concentration was above 0.4wt. %. The as-cast structure of the Mg- Mn alloys contained columnar, dendritic grains. Two types of Mn particles (equiaxed large particles and rod-like or plate-like small particles) were observed in the as-cast Mg-Mn alloys. The volume fraction of particles and the size differences between the large and small particles increased with an increase of Mn concentration.
W.Ke, E.H.Han, Y.F.Han, K.Kainer and A.A.Luo
J. P. Li et al., "The Microstructures of As-Cast Mg-Zr and Mg-Mn Alloys", Materials Science Forum, Vols. 488-489, pp. 329-332, 2005