A thermodynamically consistent constitutive model for diffusion-assisted plasticity in Ni-based superalloys
A thermodynamically consistent constitutive model for diffusion-assisted plasticity in Ni-based superalloys
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DOI：
10.1016/j.ijplas.2017.12.007
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发表时间：
2018-06
影响因子：
9.8
通讯作者：
D. Barba;E. Alabort;D. Garcia-Gonzalez;J. Moverare;Roger C. Reed;Antoine Jérusalem
中科院分区：
文献类型：
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作者：
D. Barba;E. Alabort;D. Garcia-Gonzalez;J. Moverare;Roger C. Reed;Antoine Jérusalem
本文提出了一种扩散辅助相变的弹粘塑性材料的自洽本构模型。该模型考虑了不同的变形机制，它们的时间依赖性，由微孪晶传播和发生在高温下的化学塑性耦合产生的晶体旋转。它适用于研究在600-800 °C温度范围内观察到的镍基高温合金中的化学辅助微孪晶。根据单晶高温合金MD 2拉伸蠕变试验的多方向力学数据对模型参数进行了标定。本构模型，然后实施到一个晶体塑性有限元代码来研究激活的不同的变形机制内的单晶和多晶聚集体。这样做，晶体的旋转和不同的晶体取向的蠕变寿命之间的关系被建立。结果揭示了微孪晶形成的强各向异性对合金非对称行为的关键作用及其对力学性能的相关作用。
An elasto-viscoplastic thermodynamically consistent constitutive model for diffusion-assisted phase transformations is presented here. The model accounts for the different deformation mechanisms, their time dependence, the crystal rotations produced by microtwin propagation and the chemistry-plasticity coupling occurring at high temperature. It is applied to the study of the chemically assisted microtwinning observed in Ni-based superalloys in the temperature range of 600–800 °C. The model parameters are calibrated against multi-directional mechanical data from tensile creep tests of single crystal superalloy MD2. The constitutive model is then implemented into a crystal plasticity finite element code to study the activation of the different deformation mechanisms within single crystal and polycrystalline aggregates. Doing so, a relation between the rotations of the crystal and the creep life of the different crystal orientations is established. The results eventually reveal the critical role of the strong anisotropy of microtwin formation on the asymmetric behavior of the alloy and its relevant role on the mechanical performance.