Microstructure

mechanical properties

fracture morphology and fracture mechanism of differential pressure casting Mg-10Gd-3Y-Zr alloy with solution treatment were investigated by optical microscope（OM）

scanning electron microscope（SEM）

X-ray diffraction（XRD）and tensile testing.The results show that grain size in the microstructure is increased from 73 μm to 90 μm

and hardness as wel as yield strength is firstly increased then decreased and then increased with solution temperature increasing from 500℃ to 535℃.Microstructure of T4 treated alloy is composed of α-Mg solid solution and cuboidal particles with rich（Gd+Y）phase

whose tensile strength

yield strength and elongation are 231MPa

149MPa and 4.8%

respectively

after solution treatment at 535℃ for 10 hours

exhibiting desirable comprehensive mechanical properties.The fracture morphology of the T4 treated alloy is characterized by intergranular and transgranular fracture combining with limited cleavage fracture.