Atomistic study of atomic structures and dislocation nucleation at Al/Al2Cu interfaces

• Published in: International journal of plasticity Vol. 120; pp. 115 - 126
• Main Authors: Zhou, Q., Hua, D.P., Du, Y., Ren, Y., Kuang, W.W., Xia, Q.S., Bhardwaj, V.
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 01.09.2019; Elsevier BV
• Subjects: Aluminum base alloys; Atomistic modeling; Copper; Dependence; Dislocation; Dislocations; Eutectic composites; Interface structure; Intermetallic; Mechanical analysis; Misfit dislocations; Nucleation; Plates (structural members); Interface structure; Atomistic modeling; Intermetallic; Dislocation
• ISSN: 0749-6419; 1879-2154
• DOI: 10.1016/j.ijplas.2019.04.014

The plate-like phase of Al2Cu necessitates a detailed understanding of the interface structure, which significantly governs the structural applications of AlCu alloys. Different from a metal/metal interface where only one stable interface exists, the metal eutectic composites possess multiple possible interfaces. Here, atomistic simulations were implemented to reveal a strong dependence of dislocation structure on the termination plane at the Al/Al2Cu hetero-interface. Different termination of Al2Cu phase at interfaces exhibited distinct atomic arrangements, leading to variations of γ -surface and ultimately dictate the dislocation structure. Among the four possible termination at Al2Cu (110) plane, two of them are stable in Al/Al2Cu hetero-interface, named as AlB-terminated and AlA2-terminated interfaces. The networks of misfit dislocations with different Burgers vectors of these two interfaces are also identified. Disregistry investigations of the interface showed that the misfit dislocation lines in AlB-terminated interface are curved while that in AlA2-terminated interface are straight. This is related to the relative interface energy between the stable coherent structures. These dislocation networks in turn have a bearing on the mechanical response of interfaces, as manifested by the different nucleation mechanisms of lattice dislocations. Although this work is performed on a particular Al/Al2Cu, the commonalities also exist in other eutectic composites. The detailed correlation between the interface structure and termination at metal-intermetallic interface has been recognized for the first time, which could offer novel avenues for fine-tuning eutectic composites with enhanced properties. [Display omitted] •Dislocation structures in Al/Al2Cu heterointerfaces are contingent on the termination at the interface.•The variation in stable coherent interface structures in different interfaces is related to the atomic stacking.•Interface termination strongly influences the dislocation nucleation mechanism.