Mesoscopic Finite Element Simulation Of Ferrite-based Particle Reinforced Composite Materials

The particle-reinforced metal matrix composites combines the advantages of metal and ceramic materials,which have high specific stiffness,strength,good dimensional stability,excellent damping and wear resistance.It is mainly applied in the field of aerospace,automotive industries,roads and bridges Industries.Among them,the particle type and distribution have an important influence on the mechanical properties of the composites.And the finite element method can be used to design the composite and predict its mechanical properties.However,at present most of the research mainly use Representative Volume Element(RVE)models.It is considered that the composite material is mechanically mixed from a single matrix and hard particles.Therefore,based on this,a crystal plasticity finite element model of particle reinforced composites is proposed,considering more detailed mesoscopic features such as grain boundaries,dislocation slips and lattice types,so that the simulation process is more realistic.Firstly,based on the RSA random algorithm,a multi-particle random distribution model is established.The model with a periodic boundary conditions is uniaxially stretched.The simulation results agree well with the experimental data,indicating that the model has certain reliability.Then the uniaxial tensile test of the particle-reinforced iron matrix composite model with different particle shape,volume fraction,particle size and interfacial bonding properties was carried out.The results show that the composite mechanical properties of the material are better when the particle volume fraction is 30%.The strain at the sharp corners is extremely large,which affects the load transfer effect of the matrix;the average stress inside the small particles is more,which is the main bearing phase,and the strengthening effect is more ideal;the strong interface model will form the strain band along the load direction,the load The transfer effect is better.For the weak interface model,the high strain region is mainly along the direction of the displacement load at 45 degrees or 135 degrees.Secondly,based on the Voronoi diagram algorithm and the crystal plastic constitutive model,a single crystal and a polycrystalline model considering the influence zone of the grain boundary are established.The tensile simulation results of single crystal and polycrystalline model were compared with the literature data.It was found that grains with different positions and orientations will affect the shear strain rate and ultimately affect the plastic deformation of the grains.In the case of only the grain boundary,the comprehensive mechanical properties of the composite increase with the increase of the volume fraction and the elastic modulus of the particles.The grain boundary particles reduce the internal cracking probability of the grains,and the high plastic strain region near the grain boundary region is reduced.When the particles are only distributed inside the grains,the high stress region of the matrix increases and the material strength is remarkably enhanced.However,the deformation mechanism of the material has changed from a transgranular fracture along the cleavage plane to an intergranular fracture.The improved model can study the mesoscopic characteristics of the stress-strain distribution of the micro-area of the polycrystalline material and predict the failure mode of the polycrystalline material.