微量Ag对挤压态Mg-Gd-Y-Zr合金析出行为和力学性能的影响

Effects of trace Ag on precipitation behavior and mechanical properties of extruded Mg−Gd−Y−Zr alloys

通过拉伸试验、X射线衍射、扫描电镜、电子背散射衍射和扫描透射电镜等手段研究微量Ag元素对Mg-7.5Gd-1.5Y-0.4Zr(质量分数,%)合金析出行为和力学性能的影响。结果表明,含0.5%Ag(质量分数)的Mg-GdY-Zr合金挤压后存在á0001?//挤压方向的织构组分。在225℃时效过程中,添加Ag元素不会形成新相,而是通过Ag偏聚加速析出动力学,细化β′相并增加其密度。此外,含0.5 wt.%Ag的Mg-Gd-Y-Zr合金峰时效后具有最好的强度和塑性协同性(抗拉强度为408 MPa;屈服强度为265 MPa;伸长率为12.9%)。

The effects of trace Ag element on the precipitation behaviors and mechanical properties of the Mg−7.5Gd−1.5Y−0.4Zr(wt.%)alloy by means of tensile test,X-ray diffractometry,scanning electron microscopy,electron backscattered diffractometry,and scanning transmission electron microscopy.There is an unusual texture(á0001ñ//extrusion direction)in the extruded Mg−Gd−Y−Zr alloys containing 0.5 wt.%Ag.During the aging periods at 225℃,the addition of the trace Ag does not form new precipitates,just accelerates aging kinetics,and refinesβ′precipitates,thereby increasing the number density of theβ′precipitates by Ag-clusters.Moreover,the Mg−Gd−Y−Zr alloy containing 0.5 wt.%Ag shows the most excellent synergy of strength and plasticity(408 MPa of ultimate tensile strength,265 MPa of yield strength,and 12.9%of elongation to failure)after peak-aging.