Polycrystal plasticity modeling for load reversals in commercially pure titanium
Polycrystal plasticity modeling for load reversals in commercially pure titanium
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DOI：
10.1016/j.ijplas.2019.09.013
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发表时间：
2020-02
影响因子：
9.8
通讯作者：
Jiaxiang Wang;Milovan Zecevic;M. Knezevic;I. Beyerlein
中科院分区：
文献类型：
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作者：
Jiaxiang Wang;Milovan Zecevic;M. Knezevic;I. Beyerlein
在这项工作中，我们使用多晶模型来研究商业纯钛在负载反转过程中的滑移和孪生之间的相互作用。本构响应包括各向异性弹性、晶体塑性、基于位错密度的棱柱滑移、基底滑移和金字塔型I< c+ a>滑移的硬化规律，以及两种类型的孪晶重取向的微观力学模型：{101 2 <$}伸展孪晶和{11 2 <$}收缩孪晶。该模型的主要特点是包括滑移系水平背应力发展由于位错密度积累。为了证明这一点，该模型被用来模拟应力-应变响应和纹理演变的一系列压缩-拉伸和拉伸-压缩测试进行不同的应变水平，并在两个不同的负载方向施加到一个强纹理CP-Ti板。材料参数与三个滑移模式的滑移强度的报告。该模型确定的几个系统内的金字塔< c+ a>的滑移模式中的三个滑移模式发展最背应力。研究还表明，在正向加载路径中产生的背应力促进了反向加载路径中的锥体滑移，反向加载对单调加载的相对滑移模式贡献的影响很小，但对孪晶-去孪晶行为的影响很大。这项工作突出了多晶体建模的能力，以占多个晶体滑移和孪生模式的相互依赖的性质，在正向-反向循环过程中的塑性响应的滞后，和两个来源的硬化所产生的历史相关的位错密度积累。
In this work, we use polycrystal modeling to study the interactions between slip and twinning during load reversals of commercially pure titanium. The constitutive response incorporates anisotropic elasticity, crystal plasticity, a dislocation density based hardening law for prismatic slip, basal slip, and pyramidal type I< c+ a> slip, and micromechanical model for twin reorientation on two types:{101 2¯} extension twinning and {11 2¯ 2} contraction twinning. The key feature of the model is the inclusion of slip-system level backstress development due to dislocation density accumulation. To demonstrate, the model is used to simulate the stress-strain response and texture evolution in a series of compression-tension and tension-compression tests carried out to different strain levels and applied in two different load directions to a strongly textured CP-Ti plate. Material parameters associated with the slip strengths for the three slip modes are reported. The model identifies the few systems within the pyramidal< c+ a> slip mode as developing the most backstress among the three slip modes. It also indicates that the backstresses that develop in the forward loading path promote pyramidal slip in the reversal loading path. We also find that reverse loading changes negligibly the relative slip mode contributions from monotonic loading but it strongly affects the twinning-detwinning behavior. This work highlights the ability of polycrystal modeling to account for the co-dependent nature of multiple crystallographic slip and twinning modes, the hysteresis in plastic response during the forward-reversal cycle, and the two sources of hardening engendered by history-dependent dislocation density accumulation.