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采用扫描电镜(SEM)和万能电子试验机分析和测试了不同镁含量(1%~5%,质量分数)和铝含量(4%~8%,质量分数)锌铝镁合金的凝固组织与力学性能。研究表明:当铝含量为6%时,随着镁含量的增加,Zn-6%Al-Mg合金中的Mg Zn_2相、二元Zn/Al和三元Zn/Al/Mg Zn_2共晶体数量明显增加,当镁含量为3%时达到最大值。当镁含量超过3%时,出现较多粗大的Al/Mg Zn_2二元共晶体。铝含量小于6%时,在Zn-Al-3%Mg合金中形成粗大的Mg_2Zn_(11)相和大量的Zn/Al/Mg_2Zn_(11)三元共晶体;当铝含量超过6%时,在Zn-Al-3%Mg合金中形成粗大的Mg Zn_2相和大量的Al/Mg Zn_2二元共晶体。当铝含量为6%时,Zn-6%Al-Mg合金的抗拉强度和硬度随着镁含量的增加呈现先增加后降低的趋势,但合金的延伸率一直下降,Zn-6%Al-3%Mg合金的抗拉强度和硬度最高。当镁含量为3%时,Zn-Al-3%Mg合金的抗拉强度、延伸率和硬度随着铝含量的增加都呈现先增加后降低的趋势,Zn-6%Al-3%Mg合金的综合力学性能最好。
The microstructure and mechanical properties of Zn-Al-Mg alloy with different Mg contents (1% ~ 5%, mass fraction) and Al contents (4% ~ 8%, mass fraction) were analyzed and tested by means of scanning electron microscope (SEM) and universal electronic testing machine performance. The results show that when the aluminum content is 6%, the amount of Mg Zn 2 phase, binary Zn / Al and ternary Zn / Al / Mg Zn 2 eutectic in Zn-6% Al-Mg alloy increases with the increase of Mg content Increase, reaching maximum when the magnesium content is 3%. When the content of magnesium exceeds 3%, more coarse Al / Mg Zn 2 binary eutectoid appears. The coarse Mg_2Zn_ (11) phase and a large amount of Zn / Al / Mg_2Zn_ (11) ternary eutectics are formed in Zn-Al-3% Mg alloy when the content of aluminum is less than 6%. When the content of aluminum exceeds 6% Zn-Al-3% Mg alloy formed coarse Mg Zn 2 phase and a large number of Al / Mg Zn 2 binary eutectic. When the content of aluminum is 6%, the tensile strength and hardness of Zn-6% Al-Mg alloy first increase and then decrease with the increase of Mg content, but the elongation of the alloy decreases all the time. The Zn- 3% Mg alloy has the highest tensile strength and hardness. When the content of magnesium is 3%, the tensile strength, elongation and hardness of Zn-Al-3% Mg alloy first increase and then decrease with the increase of Al content. The Zn-6% Al-3% Mg alloy The best comprehensive mechanical properties.