Model for grain boundary sliding and its relevance to optimal structural superplasticity Part 1—Theory
Model for grain boundary sliding and its relevance to optimal structural superplasticity Part 1—Theory
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晶界滑动模型及其与结构超塑性的最佳相关性第 1 部分 - 理论
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
J. Schlipf
中科院分区：
文献类型：
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作者：
K. A. Padmanabhan;J. Schlipf
实验结果的评估导致的结论是，最佳的结构超塑性结果从晶粒/相间边界滑动扩散耦合流。首先对边界滑移过程进行了分析。通过建议，区域I和IIa（区域II的低应力范围）的超塑性流动的结果从滑动扩散耦合流，和治疗介观（合作）边界滑动作为最佳超塑性的速率控制机制，应力，温度和晶粒尺寸的应变速率变形的依赖性进行了预测。然后，上述方程与应力指数n（应变速率敏感性指数m的倒数）相关。对确定速率控制过程的真实活化能进行了分析。推导出滑动产生的内部应力分布和边界粘性的表达式，并且在早期分析中预测的初始不稳定区域的存在被证明是这种方法的自然结果。MST/3074
An assessment of the experimental findings leads to the conclusion that optimal structural superplasticity results from grain/interphase boundary sliding—diffusion coupled flow. An analysis of the boundary sliding process is presented first. By suggesting that both regions I and IIa (lower stress range of region II) of superplastic flow result from sliding—diffusion coupled flow, and—treating mesoscopic (cooperative) boundary sliding as the rate controlling mechanism for optimal superplasticity, the stress, temperature, and grain size dependences of the strain rate of deformation are predicted. The above equation is then related to the stress exponent n (the inverse of the strain rate sensitivity index m). An analysis for determining the true activation energy for the rate controlling process is presented. Expressions for the distribution of internal stresses arising from sliding and the boundary viscosity are derived, and the presence of an initial unsteady region, predicted in an earlier analysis, is shown to be a natural consequence of this approach. MST/3074