Interface-mediated shear behavior of bonded aluminum substrates
M Khajehvand and H Seppanen and P Sepehrband, JOURNAL OF MATERIALS SCIENCE, 57, 20957-20973 (2022).
Molecular dynamics simulations are utilized to study the shear deformation behavior of aluminum interfaces formed through jump-to- contact (JC) mechanism. In the presence of misorientation between substrates, when shear is applied, (111)-oriented systems exhibit resistance-free sliding, whereas in the (001)- and (110)-oriented systems, dislocation multiplication (DM), which originates from the network of interfacial dislocations, is found to be the controlling mechanism. It is observed that by a decrease in the misorientation angle or an increase in the strain normal to the interface (a consequence of JC), more DM occurs. (110)-oriented systems are found to be the most prone system to DM due to the existence of dislocations with Burgers vector of a < 100 > in their interface. Ultimately, using the profile of average atomic volume along the direction perpendicular to the interface, two characterizing parameters are defined: interface volume expansion (IVE) and interface thickness (IT). IVE describes the excess free atomic volume at the interface relative to that in the bulk, and IT is an estimate of the portion of the system that is considered as the interface region (where defects are concentrated). IVE and IT are shown to have a reverse and direct relationship with the shear strength of the system, respectively, and therefore are introduced as new tools for prediction of shear deformation behavior. Calculation of the IVE and IT parameters enables linking the microscopic characteristics of the interface to shear deformation behavior, which is a controlling phenomenon in various applications. Particularly, the IT parameter is found to be very promising as the direct relationship between IT and shear strength is shown to be independent of the orientation of the interface plane.
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