Aging characteristics and high temperature properties of Mg-9Gd-3Y-0.3Zr

The microstructures and tensile properties of Mg-9Gd-3Y-0.3Zr alloys were investigated by OM,SEM and mechanical property tester. The results show that the microstructure of as-cast sample is a typical dendritic structure,the grain size of extruded sample is finer than that of the as-cast because of recrystallization. The aging response of extruded specimens is quick and marked when the samples are aged at 200 to 250 ℃ for different time,and the peak aging hardness is about HV120. The tensile strengths at 25,200,250 and 300 ℃ are 375,364,329 and 286 MPa,respectively. The maximum elongation is higher than 18% at 300 ℃. The fracture mode is mainly microvoid coalescence fracture combining with brittle cleavage fracture at room temperature,and microvoid coalescence fracture at 250-300 ℃.

The microstructures and tensile propert;.es of Mg-9Gd-3Y-0.3Zr alloys were investigated by OM, SEM and mechanical property tester. The results show that the microstructure of as-cast sample is a typical dendritic structure, the grain size of extruded sample is finer than that of the as-cast because of recrystallization. The aging response of extruded specimens is quick and marked when the samples are aged at 200 to 250℃ for different time, and the peak aging hardness is about HVI20. The tensile strengths at 25,200, 250 and 300℃ are 375,364, 329 and 286 MPa, respectively. The maximum elongation is higher than 18% at 300 ℃. The fracture mode is mainly microvoid coalescence fracture combining with brittle cleavage fracture at room temperature, and microvoid coalescence fracture at 250-300℃.