Numerical Simulation Of Mechanical Properties Of Graphene Reinforced Nickel Matrix Composites

Nickel alloy and nickel matrix composite materials are mainly used in aerospace engines,rocket thrusters,gas turbines and other high temperature components.This is because nickel as a high temperature alloy,has high strength and high temperature stability and other advantages.At present,the development of China’s aviation industry needs materials with better performance,and the traditional nickel-based high-temperature alloy is gradually replaced by nickel-based composite material,which has a broad application prospect for its development and research.This paper mainly uses Material Studio（MS）and ANSYS software to numerically simulate the mechanical properties of graphene reinforced nickel matrix composites,including the following contents:（1）CASTEP module in Acclerys Material Studio（MS）software was adopted for simulation.Firstly,the elastic modulus of the metal Ni atomic protocell was calculated.Secondly,the structure of the graphene adsorption system of Ni atoms was optimized and the system energy was calculated.The structure indicates that Ni atom belongs to chemical adsorption and has good adsorption performance.This indicates that the interfacial binding strength between graphene and Ni is high and the interface stability is strong.When the coverage is between 3.125%and 9.375%,with the increase of the coverage,the most stable adsorption position changes from the top position to the bridge position,and Ni atoms automatically aggregate in the bridge position.The adsorption energy of Ni adsorbed on graphene system under the action of stretching and compression decreases with the increase of tensile deformation.The defective graphene has stronger adsorption capacity to Ni atoms,and the interface strength between graphene and metal nickel is better.（2）A random distribution model of three-dimensional graphene reinforced nickel matrix composites was established by using the APDL command stream program in the finite element software ANSYS.The von Mises yield stress and the first principal stress distribution of the flake graphene reinforces nickel matrix composites with different aspect ratios and different volume fractions under tensile and compressive stresses were simulated.In the tensile stress field,the von Mises stress is uniformly distributed on the matrix with a small value,while it is very high on the reinforcement.Yield failure is easy to occur at the interface along the loading direction around the reinforcement.The first principal stressσ₁ is evenly distributed.As the volume fraction increases,the non-uniform distribution of stress around the reinforcement is improved.In the compression numerical simulation,the analysis of the first principal stressσ₁indicates that the maximum stress is usually present at the tips on both sides of the reinforcement perpendicular to the load direction.The composites under compression stress field are less likely to be destroyed than those under tensile stress field.（3）ANSYS software was used to establish four graphene-reinforced nickel-based composites with different aspect ratios at different volume fractions to predict their elastic modulus.The results show that the effect of length to width ratio on elastic modulus increases slightly with the increase of volume ratio.At low volume fraction,the elastic modulus of composites is higher than that of series and parallel.With the increase of the volume ratio,the increase of the elastic modulus decreases obviously.However,the elastic modulus of the composite increases with the increase of the content of the reinforcement.It indicates that the low content of graphene in the composite has a high enhancement effect on the stiffness of the material.