Effects of aging on the microstructures and mechanical properties of extruded AM50+xCa magnesium alloys

The effects of aging treatment on the microstructures and mechanical properties of extruded AM50+xCa alloys （x=0,1%,2% in mass fraction） were studied. The results indicated the secondary phase Mg 17 Al 12 precipitated from the saturated α-Mg solid solution while Al2Ca changed slightly when the aging time was increased. The hardness of extruded AM50+xCa alloys increased initially to its peak,and then dropped to reach its original hardness with the increase in aging time. With the increase in aging temperature,the hardness of the AM50+2Ca alloy decreased,whereas the hardness of AM50 and AM50+1Ca alloys decreased in the initial stages of aging treatment and increased in the later stages of aging treatment. The tensile strengths of AM50 and AM50+1Ca alloys increased after aging treatment for the precipitation of Mg 17 Al 12 phase,which increases the resistance against dislocation movement at the grain boundary; with increase in aging temperature,their tensile strengths increased. For AM50+2Ca alloy,the tensile strength declined after aging at 150?℃ and 175?℃,while it increased slightly at 200?℃. The ductility of AM50+xCa alloys （x=0,1%,2%） declined after aging treatment.

The effects of aging treatment on the microstructures and mechanical properties of extruded AM50 ＋ xCa alloys （x = 0. 1%, 2% in mass fraction） were studied. The results indicated the secondary phase Mg17Al12 precipitated from the saturated a-Mg solid solution while Al2Ca changed slightly when the aging time was increased. The hardness of extruded AM50 ＋ xCa alloys increased initially to its peak, and then dropped to reach its original hardness with the increase in aging time.