Deformation Mechanisms Dominated by Decomposition of an Interfacial Misfit Dislocation Network in Ni/NiAl Multilayer Structures.

Ni/NiAl heterogeneous multilayer structures are widely used in aerospace manufacturing because of their unique coherent interfaces and excellent mechanical properties. Revealing the deformation mechanisms of interfacial structures is of great significance for microstructural design and their engineering applications. Thus, this work aims to establish the connection between the evolution of an interfacial misfit dislocation (IMD) network and tensile deformation mechanisms of Ni/NiAl multilayer structures. It is shown that the decomposition of IMD networks dominates the deformation of Ni/NiAl multilayer structures, which exhibits distinct effects on crystallographic orientation and layer thickness. Specifically, the Ni/NiAl (100) multilayer structure achieves its maximum yield strength of 5.28 GPa at the layer thickness of 3.19 nm. As a comparison, the (110) case has a maximum yield strength of 4.35 GPa as the layer thickness is 3.01 nm. However, the yield strength of the (111) one seems irrelevant to layer thickness, which fluctuates between 10.89 and 11.81 GPa. These findings can provide new insights into a deep understanding of the evolution and deformation of the IMD network of Ni/NiAl multilayer structures.