位错芯区扩散引起的非线性滞弹性内耗峰

若干年来,我们对于出现在Al-Cu和Al-Mg系中的表现正常和反常振幅效应的坐落在室温附近的内耗峰进行了系统研究,测得的激活能接近于溶质原子在位错管道中扩散的激活能，从而认为内耗峰的基本过程是溶质原子在隹错芯内的扩散，并且提出了根据位错弯结模型的物理图像。在70年代，Windler-Gniewek等根据弦模型对于位错芯内的扩散进行了理论计算，推导出描述内耗行为的数学表达式与我们的实验结果有许多相似之处。本文对于弦模型和弯结模型进行了对比，分析了位错芯内的纵向扩散和横向扩散所引起的内耗的非线性表现以及内耗峰温和峰高随着应变振幅和测量温度而变化的情况，进一步了我们发现的室温非线性内耗峰（非线性滞弹性内耗）是由于溶质原子在位错芯内扩散所引起的。 关键词：

NONLINEAR ANELASTIC INTERNAL FRICTION PEAKS ASSOCIATED WITH DISLOCATION CORE DIFFUSION

Early since 1950, a systematic study was made on the anomalous internal friction peaks appeared in cold-worked Al-Cu and Al-Mg specimens around room temperature. The activation energy associated with these internal friction peaks was found to be close to that associated with the pipe diffusion along dislocations. Consequently the internal friction peaks were attributed to the diffusion of Cu or Mg atoms in the dislocation core in aluminium. A physical model of these internal friction peaks was suggested in terms of the dislocation kink concept. The manifestation of these anomalous internal friction peaks was found to be similar to that predicted through a detailed mathematical analysis of the dislocation core diffusion by Winkler-Gneiwek et al. according to the string model. In this paper, a critical comparison has been made between the string model and the kink model concerning this problem and it is shown that the predictions derived from the string model can be adequately applied to the case of the kink model. This confirms further that the nonlinear anelastic internal friction peaks we observed are originated from dislocation core diffusion.