Experimental investigation of the Mg-Zn-Zr ternary system at 450 degree C

• Published in: Journal of alloys and compounds Vol. 680; pp. 212 - 225
• Main Authors: Zhang, Xin, Zhang, Yi-Nan, Kevorkov, Dmytro, Medraj, Mamoun
• Format: Journal Article
• Language: English
• Published: 25.09.2016
• Subjects: Alloys; Diffraction patterns; Homogeneity; Liquids; Metal matrix composites; Phase boundaries; Ternary systems; X-rays
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2016.04.081

The Mg-Zn-Zr ternary system was experimentally investigated at 450 degree C using six diffusion couples and 16 key alloys. Four new ternary compounds, IM1, IM2, IM3 and IM4 were detected. The compositions, homogeneity ranges, phase relationships and the X-ray diffraction patterns of these compounds were identified using scanning electron microscopy coupled with energy-dispersive x-ray spectrometer and x-ray diffraction techniques. The homogeneity ranges of IM1, IM2, IM3 and IM4 are Mg sub((23-26))Zn sub(66)Zr sub((8-11)), Mg sub((15-16))Zn sub(66)Zr sub((18-19)), Mg sub((10-11))Zn sub(66)Zr sub((23-24)), and Mg sub((9-13))Zn sub((79-87))Zr sub((5-8)), respectively. IM1 compound crystallizes in an MgZn sub(2) structure type with hexagonal structure and P6 sub(3)/mmc space group. The Mg-Zn and Zn-Zr binary compounds do not have extended solid solubility into the ternary system. The phase boundaries of Mg-Zn-Zr liquid phase at 450 degree C were determined by several key alloys. The single phase liquid region extended into the ternary phase diagram only to around 1 at.% Zr. However, phase regions containing liquid along with other phases existed in the vicinity of the Mg-Zn side up to 10 at% Zr. Based on the current experimental results, the isothermal section of the Mg-Zn-Zr ternary system at 450 degree C was constructed.