Microstructure and creep behavior of the extruded Mg–4Y–4Sm–0.5Zr alloy

The microstructure and creep behavior of the extruded Mg–4Y–4Sm–0.5Zr alloy were investigated. It was shown that dynamic recrystallization (DRX) took place during extrusion at 673 K and equilibrium β precipitates were observed in the extruded alloys. Numerous fine globular β′ precipitates homogeneously formed within grains when the as-extruded alloy was aged at 473 K for 16 h, leading to effectively strengthening. The as-extruded alloy exhibits good creep resistance. The creep stress exponent n is 4.42 and the creep activation energy Q is 140.6 kJ mol−1 suggesting that dislocation climb plays a dominant role when the alloy is crept at temperatures ranging from 453 K to 493 K and at a stress of 180 MPa.