The Simulation Research Of Mechanical Properties Of Al/Ni Dissimilar Metals Based On Self-propagating Exothermic Reaction Bonding

Due to the characteristics of the large heat release and the rapid response,selfpropagating exothermic reaction bonding(SERB)formed by reactive nano-multilayers has shown the great application value in the field of micro-electromechanical systems represented by batteries.Its essence is that igniting the nano-multilayer films will cause self-propagating exothermic reactions,to melt the part of the adjacent metals and form a metallurgical bond.Studying the mechanical properties of the bonded component is vital importance to the application of SERB.However,it is difficult to describe the microscopic deformation mechanisms of the tensile process in detail through experimental means.Therefore,this paper used molecular dynamics simulation to study the micro-mechanical properties and the deformation mechanisms of aluminumnickel dissimilar metals bonding by SERB,which provided the theoretical basis and the guidance for the applications of SERB in production.Firstly,the bonding of aluminum-nickel dissimilar metals was realized based on the self-propagating reactions of Al/Ni nano-multilayer films,and the mechanical properties of aluminum and nickel components before and after bonding were compared to verify the effectiveness of SERB.The Young's modulus of the bonded component was 48.88 GPa higher than that of single-crystal aluminum and the tensile strength was also 57% higher than the diffusion-bonded Al/Ni nanowires.The application of Al/Ni nano-multilayer films for bonding an Al component to a Ni component could improve the bonding quality.Secondly,the influences of five bonding process factors(Al/Ni nano-multilayer film atomic ratio,ignition temperature,initial holding temperature,system pressure,heating rate)on the mechanical properties and the deformation mechanisms of the AlNi bonded component under the tensile load were studied by the orthogonal experimental analysis and the comparative experimental analysis,respectively.Both analysis methods have concluded that the influence of each factor on the tensile strength can be sorted as follows: Al/Ni nano-multilayer film atomic ratio> initial holding temperature> ignition temperature> system pressure> heating rate.Finally,we also analyzed the effects of the tensile temperature,the strain rate and the component size on the tensile mechanical properties of Al-Ni bonded components.With the increase of the tensile temperature,the yield strength of the bonded component decreased from 5.31 GPa to 1.83 GPa,and the tensile strength decreased from 7.0GPa to 3.74 GPa.When the tensile temperature was 100 K,a closed structure of dislocations was formed due to the strong interactions of dislocations.The strain rate had little effect on the stress-strain curve of the bonded component.As the component size increased from 30 nm to 61 nm,the yield strength of the bonded component increased from 3.53 GPa to 4.30 GPa.The total length of the fixed dislocations in the bonded component of 45 nm was as high as 393 nm.The increase of the fixed dislocations can effectively hinder the slippage of the dislocations,thereby improving the tensile strength of the materials.