摘要
为了提升一种商用镁−稀土合金EV31A(Mg−3Nd−1.5Gd−0.3Zn−0.5Zr)的塑性,探索双级时效工艺,并且研究其对合金力学性能和显微组织的影响。在实验测得的最优双级时效参数下,合金的抗拉强度和伸长率从单级时效的273 MPa和4.9%提升到288 MPa和6.6%。双级时效的总时效时间也大幅缩短,从16 h降低到2 h。HAADF-STEM表征发现,合金的主要析出相β′相与Mg−Nd二元合金中的β′相有类似的结构,并且双级时效使合金中的β′相分布更加均匀、细密,其密度大约增至2倍,而尺寸则大约减半,这解释了合金强度和塑性提升的原因。
To improve the ductility of a commercial Mg−rare earth alloy EV31A(Mg−3Nd−1.5Gd−0.3Zn−0.5Zr),a heat treatment method called double aging is explored,and its effect on mechanical properties and microstructure of the alloy is studied.Ultimate strength and elongation of the alloy can be increased to 288 MPa and 6.6%by the optimum double aging process,compared to 273 MPa and 4.9%after single aging.Time consumption of the aging process is also significantly decreased from 16 h(single aging)to 2 h.HAADF-STEM characterization shows that the primary precipitate isβ'phase,which is similar toβ'phase in Mg−Nd binary alloy.By double aging,theβ'phase is finer and more densely distributed compared with single aging,with approximately double density and half size,which explains the improvement in strength and ductility.
作者
顾侃
曾小勤
陈彬
王迎新
Kan GU;Xiao-qin ZENG;Bin CHEN;Ying-xin WANG(School of Materials Science and Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;National Engineering Research Center of Light Alloy Net Forming and State Key Laboratory of Metal Matrix Composite,Shanghai Jiao Tong University,Shanghai 200240,China)
基金
This work was supported by the National Natural Science Foundation of China(No.51825101).
