快速凝固Mg-Zn-Y合金薄带的制备及凝固组织特征

在成功制备Mg97.46Zn0.80Y1.74合金、Mg96.51Zn0.83Y2.67合金急冷快速凝固薄带的基础之上,采用XRF、XRD、SAD、DSC、SEM、显微硬度测量等分析方法系统研究了其凝固组织及显微硬度。结果表明:急冷快速凝固条件下,2种合金均形成非晶相 超细Mg12YZn相 超细hcp-Mg(Zn,Y)相,其显微硬度值大幅度提高;快速凝固Mg97.46Zn0.80Y1.74合金薄带中的hcp-Mg(Zn,Y)相晶胞在a1、a2、a3轴方向膨胀、在c轴方向收缩;快速凝固Mg96.51Zn0.83Y2.67合金薄带中的hcp-Mg(Zn,Y)相晶胞在各轴向均有膨胀;Mg96.51Zn0.83Y2.67合金薄带的熔点及热稳定性高于Mg97.46Zn0.80Y1.74合金薄带。同时对以上结果产生的原因进行了初步探讨。

Preparation and Solidified Structural Characteristics of Rapidly Solidified Mg-Zn-Y Alloy

Based on the successful preparation of rapidly solidified Mg_ 97.46 Zn_ 0.80 Y_ 1.74 and Mg_ 96.51 Zn_ 0.83 Y_ 2.67 melt spinning ribbons, their solidified structure and microhardness were studied systematically by XRF, XRD, SAD, DSC, SEM and microhardness measurement. The results indicate that: (1) in the condition of rapid solidification, the solidification microstructure of both alloys are amorphous phase ultra-fine Mg_ 12 YZn phase ultra-fine hcp-Mg(Zn,Y) phase. Compared with their mother alloys, the microhardness values increase tremendously; (2) in the rapidly solidified Mg_ 97.46 Zn_ 0.80 Y_ 1.74 melt spinning ribbons, the unit cells of hcp-Mg(Zn,Y) phase are expanded in the axis of a1, a2 and a3, whereas they are shrunk in the direction of c axis. In the rapidly solidified Mg_ 96.51 Zn_ 0.83 Y_ 2.67 melt spinning ribbons, the unit cells of hcp-Mg(Zn,Y) phase are expanded in all axis; (3) the melting point and thermal stability of Mg_ 96.51 Zn_ 0.83 Y_ 2.67 melt spinning ribbons are both higher than those of Mg_ 97.46 Zn_ 0.80 Y_ 1.74 melt spinning ribbons. The reasons of the results mentioned above are explored preliminarily.