High-resolution analytical electron microscopy study of isothermal plate-shaped products in some β-phase alloys
High-resolution analytical electron microscopy study of isothermal plate-shaped products in some β-phase alloys
复制标题
某些β相合金中等温板状产物的高分辨率分析电子显微镜研究
DOI：
10.1007/bf02649210
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
K. Shimizu
中科院分区：
文献类型：
--
作者：
T. Tadaki;K. Shimizu
The isothermal plate-shaped products in β-phase Cu-Zn-Al, Cu-Zn-Au, and Ag-Cd alloys have been studied from the viewpoints of morphology, crystal structure, and composition using a high-resolution analytical electron microscope equipped with a field-emission electron gun. It is shown that thin plate-shaped products, at early stages of the isothermal formation, exhibit crystallographic properties characteristic of martensites formed at subzero temperatures but that their compositions were definitely different from those of the surrounding matrices. Therefore, atom diffusion is conceivable to be involved in the plate formation from the nucleation stage and to occur across the coherent plate/matrix interfaces. In order for nucleation of the isothermal transformation to occur, two kinds of reactions should be thermally activated at intermediate temperatures above Tofor the martensitic transformation: (1) atom diffusion to achieve the observed composition differences between plates and matrices and (2) martensitic transformation in hypothetical alloys with compositions less than those of the original ones by the observed composition differences. The incubation periods experimentally observed should be associated with these two thermal activation processes.
