采用XRD和SEM/EDS等分析方法研究铸态和退火态富镁Mg-Zn-Zr-Y合金中相组成随着Y/Zn摩尔比的变化而演变的规律,并从相图计算的角度解释这种演变规律.结果表明:Mg-Zn-Zr-Y合金中第二相的形成严格依赖于Y/Zn摩尔比,X相(Mg12aYZn)、W相(Mg3Y2Zn3)和,相(Mg3YZwo)随着Y/Zn摩尔比的降低依次析出.与相组成对应的摩尔比或摩尔比范围定量描述如下:当Y/Zn摩尔比约为0.164时,相组成为a-Mg+I;当Y/Zn摩尔比为0.166～0.33时,相组成为a-Mg+I+W;当Y/Zn摩尔比约为0.33时,相组成为a-Mg+W;当Y/Zn摩尔比为0.33～1.32时,相组成为a-Mg+W+X; 当Y/Zn摩尔比约为1.32时,相组成为a-Mg+X.该研究为Mg-Zn-Zr-Y合金设计和合金选用提供了指导.%The phase constituent evolution of Mg-Zn-Y-Zr alloys with the mole ratio of Y to Zn both in the as-cast and as-annealed states at the Mg-rich comer was investigated by XRD and SEM/EDS analysis and was further explained from the ternary phase diagram calculation. The results show that the formation of the secondary phases in Mg-Zn-Y-Zr alloys firmly depends on the mole ratio of Y to Zn, and X (Mg12aYZn)-phase, W (Mg3Y2Zn3)-phase and I (Mg3YZn6)-phase come out in sequence as the ratio of Y to Zn decreases. The mole ratios of Y to Zn with the corresponding phase constituent are suggested quantitatively as follows: the phase constituent is a-Mg + I when the mole ratio of Y to Zn is about 0.164; a-Mg + I + W when the mole ratio of Y to Zn is in the range of 0.164-0.33;a-Mg +W when the mole ratio of Y to Zn is about 0.33; a-Mg +W+X when the mole ratio of Y to Zn is in the range of 0.33-1.32; and a-Mg +X when the mole ratio of Y to Zn is about 1.32. The results also offer a guideline for alloy selection and alloy design in Mg-Zn-Y-Zr system.
展开▼
