A three-dimensional phase-field model for computer simulation of lamellar structure formation in γTiAl intermetallic alloys
A three-dimensional phase-field model for computer simulation of lamellar structure formation in γTiAl intermetallic alloys
复制标题
DOI：
10.1016/s1359-6454(01)00014-3
复制
发表时间：
2001-07
期刊：
影响因子：
9.4
通讯作者：
Y. Wen;Long-Qing Chen;P. Hazzledine;Y. Wang
中科院分区：
文献类型：
--
作者：
Y. Wen;Long-Qing Chen;P. Hazzledine;Y. Wang
建立了α′2→α2+γ相变的三维相场模型来模拟γTiAl金属间合金中相干多域层状结构的形成。该模型考虑了与伴随相变的晶格重排相关的相干应变的影响以及界面能的各向异性。基于该模型的模拟研究成功预测了与实验观察到的多域层状结构相关的基本特征。结果表明，相干应变调节是层状结构形成的主导因素。发现相邻的γ相片层具有孪晶或准孪晶关系，其中前者占主导地位。研究发现，应变诱导的相关成核在缠绕片层的形成中起着重要作用。层状厚度由弹性应变能、界面能和本体化学自由能之间的相互作用决定。各个片层内的域是各向同性的，并且域边界是平滑弯曲的。在 (0001)α2 平面上没有观察到特殊的自调节形态模式，这与相干六角相 → O 相变换预测的模式形成有很大不同。
A three dimensional phase-field model of α′2→α2+γ transformation is developed to simulate the formation of coherent multi-domain lamellar structures in γTiAl intermetallic alloys. The model takes into account the effect of coherency strain associated with the lattice rearrangement accompanying the phase transformation, and the anisotropy in interfacial energy. Simulation studies based on the model successfully predicted the essential features associated with the multi-domain lamellar structures observed experimentally. It is shown that the coherency strain accommodation is the dominating factor responsible for the formation of the lamellar structure. The neighboring lamellae of γ phase are found to have either a twin or a pseudo-twin relationship, with the former being dominant. It is found that strain-induced correlated nucleation plays an important role in the formation of the twined lamellae. The lamellar thickness is determined by the interplay among the elastic strain energy, interfacial energy and bulk chemical free energy. Domains within individual lamellae are isotropic and domain boundaries are smoothly curved. No special self-accommodating morphological patterns are observed on the (0001)α2plane, which is very different from the pattern formation predicted for the coherent hexagonal → O-phase transformations.