Influence of Pressure and Temperature on Microstructure and Mechanical Behavior of Squeeze Cast Mg-10Gd-3Y-0.5Zr Alloy

The influence of applied pressure and pouring temperature on the microstructure and mechanical properties of a squeeze cast (SC) Mg-10Gd-3Y-0.5Zr (GW103K) alloy was systematically investigated. Our results show that increasing the applied pressure leads to microstructure refinement of the GW103K alloy with accompanying enhancement of tensile yield strength (TYS), ultimate tensile strength (UTS), and elongation to failure (E _f); a decrease in pouring temperature also leads to grain refinement and increases of TYS while decreasing the UTS and E _f. Our results show that, for the range of parameters studied herein, an applied pressure of ~160 MPa, in combination with a pouring temperature of ~993 K (720 °C), represents optimum process parameters for squeeze casting of GW103K. Using these process parameters, the TYS, UTS, and E _f of squeeze cast GW103K alloy are 151 MPa, 232 MPa, and 3.0 pct in the as-cast state, and 264 MPa, 383 MPa, and 1.5 pct, respectively, in the as-T6 heat-treated state, both of which represent significant improvements over those of the gravity cast (GC) counterpart material.