Experimental investigation and thermodynamic calculation of the Mg–Sr–Zr system

Abstract

Abstract Both experimental investigation and thermodynamic calculation were performed for the Mg–Sr–Zr system. Four decisive alloys were firstly selected and prepared using a powder metallurgy method to measure the isothermal section at 400 °C via a combination of X-ray diffraction and electron probe microanalysis. No ternary compound has been observed for this ternary system. Four three-phase regions, (Mg) + (αZr) + Mg17Sr2, Mg17Sr2 + (αZr) + Mg38Sr9, Mg38Sr9 + (αZr) + Mg23Sr6, and Mg23Sr6 + (αZr) + Mg2Sr, have been identified at 400 °C. No appreciable ternary solubility has been detected in the binary Mg–Sr compounds. Phase transition temperatures of the Mg–Sr–Zr alloys were measured by means of differential scanning calorimetry. The thermodynamic calculations match well with the experimental data in the present work, indicating that no ternary thermodynamic parameters are needed for the thermodynamic description of this ternary system. In order to verify the reliability of the current thermodynamic calculations of the Mg–Sr–Zr system, eight as-cast alloys in the Mg-rich corner were also prepared. The calculated liquidus projection is consistent with the observed primary phase regions. The present thermodynamic calculations are reliable and can be used in the development of Mg alloys.