冷却速率对Zn-30Al-1Cu合金组织的影响
Effect of Cooling Rate on Microstructure of Zn-30Al-1Cu Alloy
邱 楚, 王 锋, 熊柏青, 张永安
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作者单位：(北京有色金属研究总院 有色金属材料制备与加工国家重点实验室，北京100088
中文关键字：Zn-30Al-1Cu合金； 冷却速率； 微观组织
英文关键字：Zn-30Al-1Cu alloy; cooling rate; microstructure
中文摘要：采用金相显微镜、扫描电镜、透射电镜和X射线衍射仪研究了冷却速率对Zn-30Al-1Cu合金微观组织的影响。结果表明，Zn-30Al-1Cu合金初始凝固组织主要由初生相α'相、包围在初生相周围的包晶β相和共析组织(α + η)组成，共析组织由包晶β相分解而来。凝固后期共析胞向枝晶中心生长, 使α'相分解为层片α + η组织。随冷却速率增大，初生相由枝晶状变成等轴晶粒，尺寸也越来越小，沉积态晶粒尺寸最细小，铸态晶粒尺寸最大。冷却速率提高Cu元素在基体相中的固溶度，沉积态合金中没有发现富铜相ε，Cu元素全部固溶到基体中；普通铸造和快速凝固合金中均发现富铜相ε，它们存在于枝晶间和η相中。
英文摘要：The effects of cooling rate on microstructure of Zn-30Al-1Cu alloy were studied by OM, SEM, TEM and XRD. The results show that the primitive microstructure consists of the aluminum-rich α' phase, the zinc-rich β phase which formed around the edges of the primary α' phase and the well-formed eutectoid α + η lamellae or irregularly complex structures through β decomposition, then these cells grew into the low-aluminum α' phase cores of the dendrits to make α' phase form lamella structures α + η. With the increase of cooling rate, the dendrite primary α' phase transformes into equiaxed grains and their size becomes smaller, at the same time the solution of Cu in matrix phases is improved. The Cu-rich phase ε can not be found in as-deposited alloy, as all the copper elements dissolved in the matrix phases. The Cu-rich phase ε can be found both in as-cast alloy and as-quenched chilling alloy, and most of them are formed in inter-dendrites and η phases.