Effect of Minor Ag and Ce Additions on Hot Tearing Susceptibility of Mg–10Gd–3Y–0.5Zr Alloy

Mg–10Gd–3Y–0.5Zr alloy castings have great potential for aerospace applications due to their excellent tensile and creep properties. Thus, the hot tearing behavior of these alloys is an important characteristic to be investigated for engineering applications. In this study, effect of minor addition of Ag (0.5 wt%) and Ce (0.5 wt%) on hot tearing susceptibility (HTS) of Mg–10Gd–3Y–0.5Zr (VW103) alloy is investigated using a constrained rod casting apparatus equipped with a load cell and data acquisition system. The macrostructure and microstructure of the tears are characterized by Optical Microscope and Scanning Electron Microscope. Results indicate Ag and Ce addition worsen the hot tearing resistance of VW103 alloy. The addition of Ag remarkably increases susceptible freezing range and coefficient of thermal expansion (CTE), and sharply decreases the residual liquid fraction that can be involved in feeding tears, thus enhancing the HTS of the VW103 alloy. The addition of Ce significantly increases grain size and CTE, thereby increasing the HTS of the VW103 alloy. Discussion from the perspective of strain and liquid feeding is incorporated to clarify the different hot tearing of VW103, VW103–0.5Ce and VW103–0.5Ag alloys.