高压凝固Al-17Zn-1.5Mg合金组织与显微硬度

Microstructure and microhardness of high pressure solid ification Al-17Zn-1.5Mg alloy

利用扫描电镜、X射线衍射仪和显微硬度计对常压及6 GPa高压下凝固的Al-17Zn-1.5Mg合金的组织和显微硬度进行了研究。结果表明,Al-17Zn-1.5Mg合金在常压凝固条件下,由α-Al相和MgZn2相组成,其中α-Al相长成粗大的枝晶,大量针状第二相位于枝晶间位置,相互连接形成网络状。当该合金在6 GPa高压下凝固时,枝晶组织显著细化,第二相尺寸减小、数量减少,形态变成点粒状。合金高压凝固后,显微硬度增加了21%。

This paper is an effort to study the microstructure and the microhardness of Al-17Zn-1.5Mg alloy solidified at normal pressure and 6 GPa high pressure by using SEM, XRD and microhard- ness tester. The results show that Al-17Zn-1.5Mg alloy, subjected to normal pressure solidification condition consists of α - Al phase and MgZn2 phase, α - Al phase grows to be the coarsened dendrite, and many needle-like MgZn2 phases are located among the dendrite, linking together to form the reticulation. Solidifying the alloy at 6 GPa high pressure results in the size of the second phases, the reduced amount of them, and the under high pressure, the alloy shows the microhardness of up to obviously refined dendrites, the reduced graininess of morphology. After solidified 21%.