Zn在AlSiCuMg合金时效过程中的作用

研究了微量合金元素Zn对高强度铸造合金Al-Si-Cu-Mg时效过程的影响.通过差热分析和透射电镜等分析测试方法表明：当锌的添加量在w(Zn)=0.1%～1.0%时，可提高合金的时效峰硬度，加快合金的硬化速度.当Zn含量为0.5%时，合金的时效峰最高，当Zn含量增大到w(Zn)=1%时，硬度有所降低，但仍高于无Zn合金.通过DSC和TEM分析显示，微量的Zn固溶于基体中，加快了亚稳相的析出，较早地形成了细小而密集的亚稳相，从而使合金获得了较高的峰时效硬度.

Effect of Zn in aging process of Al-Si-Cu-Mg cast alloy

The influence of trace Zn on the aging process of high strength Al-Si-Cu-Mg cast alloy was investigated.It is noted through DSC and TEM analysis that the addition of 0.1% to 1.0% Zn into the AlSi-Cu-Mg alloy can promote the age-hardening process and increases the hardness of the alloy under the condition of peak aging.When the content of Zn is 0.5%,the highest hardness is obtained.With increasing the content of Zn to 1%,the hardness of the alloy decreases,but is still higher than that of the alloy without adding Zn.The results of DSC and TEM analysis reveal that the addition of trace Zn promotes the precipitation of fine metastable phases and lead to the increase in hardness of the alloy.