High-temperature strength of dispersion-hardened single crystals II. Theory
High-temperature strength of dispersion-hardened single crystals II. Theory
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DOI：
10.1080/14786437708232636
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发表时间：
1977-04
影响因子：
1.6
通讯作者：
R. Shewfelt;L. M. Brown
中科院分区：
文献类型：
--
作者：
R. Shewfelt;L. M. Brown
本文提出了弥散硬化单晶屈服应力随温度和应变速率变化的理论。该理论假设位错保持在它们的滑移面上，除了在某些颗粒处，位错通过局部地越过这些颗粒而绕过这些颗粒。通过局部爬升绕过的颗粒数量取决于应变速率和温度。本文描述了一个计算机程序，它模拟位错通过随机排列的点障碍物，其中有些是通过爬升绕过。利用该程序得到的屈服应力、温度和应变速率之间的关系与实验结果相当吻合。最重要的计算结果是，位错速度可以指数依赖于所施加的应力，即使所需的时间为位错克服一个单独的障碍只依赖于弱的应力。
Abstract A theory of the yield stress of dispersion-hardened single crystals as a function of temperature and strain rate is described. This theory assumes that the dislocations remain on their slip planes, except at some particles which the dislocations by-pass by climbing locally over these particles. The number of particles by-passed by local climb depends on the strain rate and temperature. A computer programme which simulates a dislocation going through a random array of point obstacles some of which are by-passed by climb is described. The relation between yield stress, temperature and strain rate obtained using this programme agrees reasonably well with experiment. The most important result of the calculations is that the dislocation velocity can depend exponentially on the applied stress even though the time required for the dislocation to overcome an individual obstacle depends only weakly on the stress.