Whisker formation and the mechanism of superplastic deformation
Whisker formation and the mechanism of superplastic deformation
复制标题
晶须形成与超塑性变形机制
DOI：
10.1016/1359-6454(95)00176-x
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发表时间：
1996
期刊：
影响因子：
9.4
通讯作者：
H. Conrad
中科院分区：
文献类型：
--
作者：
W. Cao;X. Lu;H. Conrad
研究了7475铝合金超塑变形过程中晶须的形态和形成过程与温度、应变速率和外加电场的关系。晶须细至0.1 μm，长至100 μm。它们的密度和长度增加与测试温度和应变速率的降低，并与所施加的电场。晶须的形成不能用位错或空位扩散机制来解释。相反，它们的形态和所涉及的高应变速率表明，该机制更可能是最初在晶界处的液体状物质的粘性流动。扫描电镜观察表明，晶须是由晶界滑动形成的流线形成的。这有力地表明，晶界滑动的机制也可以是液体状的晶界材料的粘性流动。
The morphology and formation process of the whiskers which developed during the superplastic deformation of 7475 Al were studied as a function of temperature, strain rate and externally applied electric field. The whiskers were as fine as 0.1 μm and as long as 100 μm. Their density and length increased with test temperature and with decrease in strain rate, and with an applied electric field. The formation of the whiskers could not be explained by a dislocation or vacancy diffusion mechanism. Rather, their morphology and the high strain rates involved suggested that the mechanism is more likely viscous flow of a liquid-like substance originally at the grain boundaries. SEM observations revealed that the whiskers formed from flow lines which developed from grain boundary sliding. This strongly suggests that the mechanism of grain boundary sliding could also be viscous flow of a liquid-like, grain boundary material.