Effects of electric current on solid state phase transformations in metals
Effects of electric current on solid state phase transformations in metals
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DOI：
10.1016/s0921-5093(00)00780-2
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发表时间：
2000-08-15
期刊：
影响因子：
6.4
通讯作者：
Conrad, H
中科院分区：
文献类型：
--
作者：
Conrad, H
考虑电流对金属中以下固态转变的影响：（1）扩散偶中金属间化合物的形成和生长，（2）沉淀，（3）非晶合金的结晶以及（4）冷加工金属的再结晶和晶粒生长。金属间化合物的形成和生长与电迁移理论定性一致。关于沉淀，电流可以增强或延迟沉淀速率，具体取决于合金、电流密度及其频率。重要的因素似乎是电流对淬火空位的影响和内应力的存在。两者都是连续的直流电。电流和高电流密度电脉冲提高了非晶合金的结晶速率。这种效应比简单的电迁移理论所能解释的要大，并且表明大量原子的协同运动。电脉冲提高了冷加工金属的再结晶速率，但阻碍了随后的晶粒生长。再结晶速率的提高主要是由于阿伦尼乌斯速率方程的指前因子的增加，该因子被认为是指形核速率。随后晶粒生长的延迟是由于新形成的晶粒内残余位错密度较低。 (C) 2000 Elsevier Science S.A. 保留所有权利。
The influence of an electric current on the following solid state transformations in metals are considered: (1) intermetallic compound formation and growth in diffusion couples, (2) precipitation, (3) crystallization of amorphous alloys and (4) recrystallization and grain growth of cold worked metals. The formation and growth of intermetallic compounds were in qualitative accord with electromigration theory. Regarding precipitation, an electric current can either enhance or retard the precipitation rate, depending on the alloy, the current density and its frequency. Important factors appear to be the effect of current on the quenched-in vacancies and the presence of an internal stress. Both a continuous d.c. current and high current density electropulsing enhanced the crystallization rate of amorphous alloys. The effects are greater than can be explained by simple electromigration theory and suggest the cooperative motion of a larger number of atoms. Electropulsing enhanced the recrystallization rate of cold worked metals, but retarded subsequent grain growth. Enhancement of the recrystallization rate resulted mainly from an increase in the pre-exponential factor of the Arrhenius rate equation, which is considered to refer to the nucleation rate. Retardation of subsequent grain growth resulted from a lower residual dislocation density within the newly-formed grains. (C) 2000 Elsevier Science S.A. All rights reserved.