Dendritic morphology observed in the solid-state precipitation in binary alloys
Dendritic morphology observed in the solid-state precipitation in binary alloys
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DOI：
10.1007/s11661-999-0089-6
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发表时间：
1999-06-01
影响因子：
2.8
通讯作者：
Qamar, I
中科院分区：
文献类型：
--
作者：
Husain, SW;Ahmed, MS;Qamar, I
Cu-Al β相合金中γ（2）相的析出以枝晶形态出现。这种形态在固态转变中很少观察到。早期有报道称，当Cu-Zn β相合金从高温冷却时，γ析出物以树枝状形成。研究了这两种合金体系的特征，以寻找促进固态转变中枝晶形态的因素。快速的体扩散和快速的界面反应动力学将促进这种形态。当母相和沉淀物之间存在晶体学相似性时，原子附着到生长界面的动力学预计是快速的。我们已经预测了许多二元合金系统中的固态析出的枝晶形态简单地基于这种晶体学的相似性。这些合金除了Cu-Al和Cu-Zn之外，还包括Ag-Li、Ag-Zn、Cu-Ga、Au-Zn和Ni-Zn系中的β相合金，Cu-Sn和Ag-Cd系中的γ相合金，以及Au-Cd系中的δ相合金。在这些合金中，制备了Ag-Zn、Ni-Zn、Ag-Cd和Cu-Sn系统的合金，并且确实发现析出物以树枝状形成。
The precipitation of gamma(2) phase in Cu-Al beta-phase alloys has been observed to occur in the dendritic morphology. Such morphology is rarely observed in the solid-state transformations. Earlier it was reported that the gamma precipitates were formed in the dendritic shape when Cu-Zn beta-phase alloys were cooled from high temperature. The characteristics of these two alloy systems have been examined to find the factors promoting the dendritic morphology in the solid-state transformations. Rapid bulk diffusion and fast interfacial reaction kinetics would promote such morphology. The kinetics of atom attachment to the growing interface is expected to be fast when crystallographic similarities exist between the parent phase and the precipitate. We have predicted the dendritic morphology in the solid-state precipitation in many binary alloy systems simply based on such crystallographic similarities. These alloys include, in addition to Cu-Al and Cu-Zn, the beta-phase alloys in Ag-Li, Ag-Zn, Cu-Ga, Au-Zn, and Ni-Zn systems, gamma-phase alloys in Cu-Sn and Ag-Cd systems, and delta-phase alloys in Au-Cd system. Of these, the alloys in Ag-Zn, Ni-Zn, Ag-Cd, and Cu-Sn systems were prepared and it was indeed found that the precipitates formed in the dendritic shape.