加入Al-5Ti-B細(xì)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(xì)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(dú)或復(fù)合添加Al-2Zr-Sc中間合金和Al-5Ti-B細(xì)化劑的條件下對鋁鋅鎂合金進(jìn)行細(xì)化處理，研究了不同細(xì)化條件下鑄態(tài)鋁鎂鋅合金的顯微組織和力學(xué)性能。結(jié)果表明：單獨(dú)加入質(zhì)量分?jǐn)?shù)為0.4%的Al-2Zr-Sc中間合金或Al-5Ti-B細(xì)化劑都可以細(xì)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(qiáng)度；復(fù)合添加質(zhì)量分?jǐn)?shù)均為0.2%的Al-2Zr-Sc中間合金和Al-5Ti-B細(xì)化劑后，晶粒的細(xì)化效果最優(yōu)，相比于基體合金，平均晶粒尺寸減小了20 μm，抗拉強(qiáng)度提高了32%，這主要是細(xì)晶強(qiáng)化和析出強(qiáng)化共同作用的結(jié)果；晶界處長桿狀第二相的存在導(dǎo)致復(fù)合細(xì)化合金的伸長率比單獨(dú)細(xì)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.