加入Al-5Ti-B細化劑和Al-2Zr-Sc中間合金后鋁鋅鎂合金的組織和拉伸性能

加入Al-5Ti-B細化劑和Al-2Zr-Sc中間合金后鋁鋅鎂合金的組織和拉伸性能Microstructures and Mechanical Properties of Al-Zn-Mg Alloy after Adding Al-5Ti-B Refiner and Al-2Zr-Sc Intermediate Alloy

在單獨或復合添加Al-2Zr-Sc中間合金和Al-5Ti-B細化劑的條件下對鋁鋅鎂合金進行細化處理，研究了不同細化條件下鑄態鋁鎂鋅合金的顯微組織和力學性能。結果表明：單獨加入質量分數為0.4%的Al-2Zr-Sc中間合金或Al-5Ti-B細化劑都可以細化鋁鎂鋅合金的晶粒，且加入Al-2Zr-Sc中間合金后有Al3（Sc，Zr）相析出，提高了合金的抗拉強度；復合添加質量分數均為0.2%的Al-2Zr-Sc中間合金和Al-5Ti-B細化劑后，晶粒的細化效果最優，相比于基體合金，平均晶粒尺寸減小了20 μm，抗拉強度提高了32%，這主要是細晶強化和析出強化共同作用的結果；晶界處長桿狀第二相的存在導致復合細化合金的伸長率比單獨細化合金的低。

Al-Zn-Mg alloy was refined with the single or compound addition of Al-2Zr-Sc intermediate alloy and Al-5Ti-B refiner. The microstructures and mechanical properties of as-cast Mg-Al-Zn alloys prepared under different refining conditions were studied. The results show that the grains were refined by single adding 0.4wt% Al-5Ti-B refiner or 0.4wt% Al-2Zr-Sc intermediate alloy, and the tensile strength was improved by Al3(Sc,Zr) phases after the addition of 0.4wt% Al-2Zr-Sc intermediate alloy. The refining effects of grains was best after compound addition of 0.2wt% Al-5Ti-B and 0.2wt% Al-2Zr-Sc, compared with the alloy before adding, the average grain size of the alloy after compound addition was reduced by 20 μm, and tensile strength was increased by 32%, which was result of grain strengthening and dispersion strengthening. The second phase with long rod shape caused the elongation of the alloy after compound refining was lower than that of the alloy after single refining.