Grain size dependence of the plastic deformation kinetics in Cu
Grain size dependence of the plastic deformation kinetics in Cu
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DOI：
10.1016/s0921-5093(02)00238-1
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发表时间：
2003-01
期刊：
影响因子：
6.4
通讯作者：
H. Conrad
中科院分区：
文献类型：
--
作者：
H. Conrad
在77-373 K温度范围内，分析了晶粒尺寸d对Cu塑性变形动力学的影响，以确定晶粒尺寸对应变速率控制机制的影响。发现了三种粒度区域：区域I（d ≤ 10−6-10− 3 m）、区域II（d ≤ 10−8-10− 6 m）和区域III（d<10− 8 m）。位错胞结构的特点制度II，不再出现在制度II。晶内位错活动的缺乏是第三机制的特征。以下机制被认为是控制速率的机制：（a）机制I，位错的交叉;（B）机制I，位错堆积促进的晶界剪切;（c）机制III，晶界剪切。晶粒尺寸对区域I中交叉机制的主要影响是对移动的和森林位错密度的影响;区域II中的影响是对位错数量和晶界原子位置的影响;区域III中的影响是对晶界原子位置的影响。从一种状态到另一种状态的转变晶粒尺寸取决于应变速率和温度。晶体结构也很重要。
Data on the effect of grain size d in the range of nm to mm on the plastic deformation kinetics of Cu at 77–373 K are analyzed to determine the influence of grain size on the strain rate-controlling mechanism. Three grain size regimes were identified: Regimes I (d≈10−6–10−3m), II (d≈10−8–10−6m) and III (d<∼10−8m). A dislocation cell structure characterizes Regime II, which no longer occurs in Regime II. The absence of all intragranular dislocation activity characterizes Regime III. The following mechanisms were concluded to be rate-controlling for ε ̇ ≈10−5–10−3s−1: (a) Regime I, intersection of dislocations; (b) Regime I, grain boundary shear promoted by dislocation pile-ups; and (c) Regime III, grain boundary shear. The major effect of grain size on the intersection mechanism in Regime I is on the mobile and forest dislocation densities; the effect in Regime II is on the number of dislocations and on the number of grain boundary atom sites; the effect in Regime III is on the number of grain boundary atom sites. The transition grain size from one regime to another depends on the strain rate and temperature. Crystallographic texture is also important.