Pilania Ghanshyam, Thijsse Barend J, Hoagland Richard G, Lazić Ivan, Valone Steven M, Liu Xiang-Yang
Materials Science and Technology Devision, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA and.
Department of Materials Science and Engineering, Delft University of Technology, Mekelweg 2, 2628 Delft, The Netherlands.
Sci Rep. 2014 Mar 27;4:4485. doi: 10.1038/srep04485.
We study the coherent and semi-coherent Al/α-Al2O3 interfaces using molecular dynamics simulations with a mixed, metallic-ionic atomistic model. For the coherent interfaces, both Al-terminated and O-terminated nonstoichiometric interfaces have been studied and their relative stability has been established. To understand the misfit accommodation at the semi-coherent interface, a 1-dimensional (1D) misfit dislocation model and a 2-dimensional (2D) dislocation network model have been studied. For the latter case, our analysis reveals an interface dislocation structure with a network of three sets of parallel dislocations, each with pure-edge character, giving rise to a pattern of coherent and stacking-fault-like regions at the interface. Structural relaxation at elevated temperatures leads to a further change of the dislocation pattern, which can be understood in terms of a competition between the stacking fault energy and the dislocation interaction energy at the interface. Our results are expected to serve as an input for the subsequent dislocation dynamics models to understand and predict the macroscopic mechanical behavior of Al/α-Al2O3 composite heterostructures.
我们使用混合的金属 - 离子原子模型通过分子动力学模拟研究了相干和半相干的Al/α - Al₂O₃界面。对于相干界面，研究了Al端接和O端接的非化学计量界面，并确定了它们的相对稳定性。为了理解半相干界面处的失配调节，研究了一维（1D）失配位错模型和二维（2D）位错网络模型。对于后一种情况，我们的分析揭示了一种界面位错结构，它由三组平行位错组成的网络构成，每组位错都具有纯刃型特征，在界面处产生了相干和堆垛层错状区域的图案。高温下的结构弛豫导致位错图案的进一步变化，这可以从界面处堆垛层错能和位错相互作用能之间的竞争来理解。我们的结果有望为后续的位错动力学模型提供输入，以理解和预测Al/α - Al₂O₃复合异质结构的宏观力学行为。
