A dipole model for the cross-slip of screw dislocations in fee metals
A dipole model for the cross-slip of screw dislocations in fee metals
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DOI：
10.1080/01418610208235684
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发表时间：
2002-06
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影响因子：
--
通讯作者：
L. M. Brown
中科院分区：
文献类型：
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作者：
L. M. Brown
本文试图使交叉滑移的观测和理论与最近的循环塑性模型和晶体的疲劳极限相一致。根据这一观点，分离两个符号相反的螺位错所需的应力，正好在交叉滑移相互湮灭的点上，控制着线性（阶段II）硬化结束时的应力τIII和循环应力-应变曲线中的饱和应力[sgrave]。它表明，在确认的结论，许多早期的研究人员，直接湮灭的位错不能解释的温度依赖性的应力，虽然它可以解释观察到的银和铜在液氦温度。基于Hirsch的工作，提出了一个应力辅助的凹凸迁移的模型，如果迁移的激活能在铜、镍和铝中约为0.1 eV，则该模型似乎能够解释观察结果。该模型的一个副产品是一个可能的重新解释的Bordoni峰在阻尼的面心金属慢跑迁移。
Abstract An attempt is made to reconcile observations and theories of cross-slip with recent models of cyclic plasticity and the fatigue endurance limit of crystals. According to this view, the stress required to separate two screw dislocations of opposite signs, which are just on the point of mutual annihilation by cross-slip, controls both the stress τIII at the end of linear (stage II) hardening and the saturation stress [sgrave]sat in the cyclic stress-strain curve. It is shown, in confirmation of conclusions by many earlier researchers, that direct annihilation of the dislocations cannot account for the temperature dependence of the stress, although it might account for observations on silver and copper at liquid-helium temperature. Based on the work of Hirsch, a model of stress-aided migration of jogs is proposed, which seems able to account for the observations if the activation energy for the migration is about 0.1 eV in copper, nickel and aluminium. A by-product of the model is a possible reinterpretation of the Bordoni peaks in the damping of face-centred metals in terms of jog migration.