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电流对金属超塑性变形中晶内位错形态的影响
引用本文:侯东芳,董晓华,李尧,游敏,王选择.电流对金属超塑性变形中晶内位错形态的影响[J].三峡大学学报(自然科学版),2002,24(4):348-350.
作者姓名:侯东芳  董晓华  李尧  游敏  王选择
作者单位:1. 三峡大学机械与材料学院,湖北,宜昌,443002
2. 江汉大学机电与建筑工程学院,湖北,武汉,430019
基金项目:湖北省教委科研计划项目(98C099),国家自然科学基金资助项目(59201010)
摘    要:在7475铝合金超塑性变形过程中沿拉伸方向对试样通以脉冲电镜,对变形后试样的透射电镜观察发现晶内位错呈顺电子流动方向排列的形态,而且位错密度有增加的迹象,分析认为这种位错形态的产生源于由脉冲电流而引起的电子风对位错段产生的一个类似于外加应力的电子风力,此力促进了位错的运动。由于大部分位错被合金中的沉淀相粒子钉扎住,因此位错的自由端在电子风力的推动下绕沉淀相粒子转动,直至位错线与电流方向平行,另外电子风力也会促进被阻塞在沉淀相粒子处的位错团的移动,从而促进了晶内位错的增殖,提高了位错密度。

关 键 词:电流  金属  超塑性变形  脉冲电镜  位错
文章编号:1007-7081(2002)04-0348-03
修稿时间:2002年3月31日

Effect of Current Pulses on Intragranular Dislocations During Superplastic Deformation of Metals
Hou Dongfang Dong Xiaohua Li Yao You Min Wang Xuanze.Effect of Current Pulses on Intragranular Dislocations During Superplastic Deformation of Metals[J].Journal of China Three Gorges University(Natural Sciences),2002,24(4):348-350.
Authors:Hou Dongfang Dong Xiaohua Li Yao You Min Wang Xuanze
Abstract:Direct current pulses were introduced along the stretching direction into the 7475 aluminum specimens which were undergoing superplastic deformation. TEM (transmission electron microscopy) observations revealed that the intragranular dislocations were arranging along the direction of flowing electrons, and the density of dislocations inside the grains was increased as well. The reason that arouses this unique dislocation morphology is attributed to the existence of electron wind force (similar to the external stress) , which is created by the current pulses. This electron wind force is exerted on dislocation segments and accelerates the sliding of dislocations. Because most of the dislocations are anchored by the precipitated-phase particles, the free ends of dislocations are pushed moving and turned around with these particles as their centers, until the dislocation lines are settled parallel to the direction of current. In addition, the electron wind force will also enhance the mobility of dislocation groups, that are blocked at the sites of depositional particles, leading to the accruement of dislocations and increases the density of intragranular dislocations.
Keywords:superplastic deformation  direct current pulse  dislocation
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