加入Al-5Ti-B细化剂和Al-2Zr-Sc中间合金后铝锌镁合金的组织和拉伸性能

Microstructures and Mechanical Properties of Al-Zn-Mg Alloy after Adding Al-5Ti-B Refiner and Al-2Zr-Sc Intermediate Alloy

在单独或复合添加Al-2Zr-Sc中间合金和Al-5Ti-B细化剂的条件下对铝锌镁合金进行细化处理,研究了不同细化条件下铸态铝镁锌合金的显微组织和力学性能。结果表明:单独加入质量分数为0.4%的Al-2Zr-Sc中间合金或Al-5Ti-B细化剂都可以细化铝镁锌合金的晶粒,且加入Al-2Zr-Sc中间合金后有Al3(Sc,Zr)相析出,提高了合金的抗拉强度;复合添加质量分数均为0.2%的Al-2Zr-Sc中间合金和Al-5Ti-B细化剂后,晶粒的细化效果最优,相比于基体合金,平均晶粒尺寸减小了20μm,抗拉强度提高了32%,这主要是细晶强化和析出强化共同作用的结果;晶界处长杆状第二相的存在导致复合细化合金的伸长率比单独细化合金的低。

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 20μm,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.