Molecular Dynamics Evaluation of the Effects of Zinc on the Mechanical Properties of Aluminum Alloys

Abstract

We propose a potential model to represent aluminum 7075 alloys and use the model to analyze their mechanical behaviors under different strain rates at the molecular level. Although aluminum 7075 alloy has been used in various fields, a model that takes all the components of the alloy into consideration has not yet been proposed; thus, simulation at the molecular level has not yet been performed. Especially, as for the zinc, the modified embedded atomic method (MEAM) potential parameters were not available because the axial ratio of zinc is larger than 1. Our work overcomes this problem by proposing a potential model capable of considering all the elements comprising aluminum 7075 alloys. Our approach involves applying the verified embedded atom method (EAM), incorporating potential parameters of zinc to the MEAM potential parameters, and utilizing the existing MEAM potential parameters of the other elements. Using the proposed potential model, we created molecular dynamics models of aluminum 7075 alloys both with and without the consideration of zinc. The mechanical properties of the two models under different strain rates are compared, and the effects of considering zinc on the alloy are investigated. As a result, it is observed that the model that possesses zinc shows higher yield stress and ultimate tensile strength than the model that does not have zinc. Moreover, suppression of the partial dislocation is noticed when zinc is present. The inclusion of zinc enhances the strength by inhibiting partial dislocation. This proposed model will be useful to analyze the mechanical behaviors of other alloys containing zinc.