Dislocation structures in zirconium and zircaloy-4 fatigued at different temperatures
Dislocation structures in zirconium and zircaloy-4 fatigued at different temperatures
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不同温度下疲劳的锆和 zicaloy-4 中的位错结构
DOI：
10.1007/s11661-997-0232-1
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
H. Gu
中科院分区：
文献类型：
--
作者：
Lin Xiao;H. Gu
利用透射电子显微镜（TEM）研究了纯锆和锆-4合金在拉-推应变控制下疲劳时，随试验温度和循环应变范围变化的特征位错结构的发展。滑移面和孪晶面由标准的赤平极射迹线分析技术确定。在室温至873 K的疲劳过程中，锆和锆合金-4的变形模式主要为一级滑移{100}。锥体滑移{2}在673 K和高循环应变范围内被激活，而基底滑移{0001}仅出现在873 K疲劳的试样中。{102}、{111}和{112}型孪晶在室温下疲劳的试样中被检测到。随着测试温度的升高，孪晶变得不那么频繁。描述了循环变形模式作为塑性应变范围和试验温度的函数的示意图。随着试验温度和应变范围的增加，纯锆疲劳试样中的位错组态由平面排列向胞状排列演变。4Cr 18 Al 2 O3合金的疲劳位错结构在室温下为平行位错线，在673 K下为胞状位错，在873 K下为两组近似相互垂直的位错带。最后，分别定性地建立了锆合金和镍铬合金疲劳位错-结构随循环应变范围和试验温度的演化图。讨论了疲劳机制的影响因素以及位错斑图演化的热力学和动力学判据。
The development of characteristic dislocation structures in pure zirconium and zircaloy-4 fatigued under pull-push strain control as the testing temperature and the cyclic strain range varied was examined using a thin-foil transmission electron microscopy (TEM) technique. The slip planes and the twinning planes were determined by a standard stereographic trace analysis technique. The first-order prismatic slip {100} is the primary deformation mode in zirconium and zircaloy-4 fatigued from room temperature (RT) to 873 K. The pyramidal sli {2} is activated at 673 K and at high cyclic strain ranges, whereas the basal slip {0001} only appears in those specimens fatigued at 873 K. The {102}, {111}, and {112} types of twins were detected in specimens fatigued at RT. Twinning becomes less frequent as the testing temperature increases. The schematic map of the cyclic deformation modes as a function of the plastic strain range and the test temperature is described. The dislocation configurations in fatigued pure zirconium specimens evolve from a planar arrangement to a cell structure as the test temperature and the strain range increase. For zircaloy-4, the fatigued dislocation structure is parallel dislocation lines at RT, cells at 673 K, and two sets of approximate mutually perpendicular dislocation bands at 873 K, respectively. Finally, the fatigued dislocation-structure evolution map with the cyclic strain range and the test temperature are qualitatively established for zirconium and zircaloy-4, respectively. The effect factors on the fatigue mechanism and the thermodynamic and dynamic criteria of the dislocation-pattern evolution are discussed.