A probabilistic twin nucleation model for HCP polycrystalline metals
A probabilistic twin nucleation model for HCP polycrystalline metals
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DOI：
10.1098/rspa.2009.0661
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发表时间：
2010-09-08
影响因子：
3.5
通讯作者：
Tome, C. N.
中科院分区：
文献类型：
--
作者：
Beyerlein, I. J.;Tome, C. N.
本文提出了六方密排金属形变孪晶形核的基本概率理论。孪晶成核被认为依赖于应力下晶界缺陷（GBD）分解成所需数量的孪晶部分以产生孪晶核。成功的转换事件的数量被认为是遵循一个随机泊松过程，其中的速率被假定为增加与局部应力。从这个概念出发，导出了形成孪核的临界应力的概率分布，其中分布的参数与GBD的性质有关。该理论实施到HCP金属的多尺度本构模型中，以测试其预测能力对以前在76和300 K下变形的纯锆的测量。
This article presents a basic probabilistic theory for the nucleation of deformation twins in hexagonal close packed (HCP) metals. Twin nucleation is assumed to rely on the dissociation of grain boundary defects (GBDs) under stress into the required number of twinning partials to create a twin nucleus. The number of successful conversion events is considered to follow a stochastic Poisson process where the rate is assumed to increase with local stress. From this concept, the probability distribution for the critical stress to form a twin nucleus is derived wherein the parameters of the distribution are related to properties of the GBDs. The theory is implemented into a multi-scale constitutive model for HCP metals in order to test its predictive capability against measurements made previously on pure zirconium deformed at 76 and 300 K.