Finite Element Analysis Of Thermal Residual Stress Of Particle-reinforced Iron-matrix Composite

Particle reinforced metal matrix composites have a wide application onengineering because of their properties that include cost-effective, easy to fabricate,simply to be processed and wear-resisting et al. As a member of these materials, Ironmatrix composites with low-density, high-stiffness, high-strength particles arerecognized as promising engineer materials in industry. The particle reinforcediron-matrix composites inevitably work in the high temperature environment duringtheir fabrication, processing and service. For example, they should be hot treated beforebeing machined and bear the thermal cycling loads during the service. Due to thetemperature gradient and physical property difference between particle and matrix,thermal residual stress occurs on the interface of particle and matrix. A large number ofstudies have shown that the thermal residual stress existing in the iron-matrixcomposites has the negative influence on composites’ mechanical property, and thenservice life of the iron-matrix composites will reduce.Firstly，this paper uses the axial symmetry unit cell model to built the finiteelement model of carbide particle reinforced iron-matrix composites which is based onthe finite element analysis of thermal stress in the ANSYS, and then uses ANSYS tocalculate the thermal stress of the model counting the hot treatment of the niobiumcarbide reinforced iron-matrix composites. Taking these factors into consideration whenanalyze the thermal stress:1physical property of particle and matrix,2hot treatmentprocess,3shape of the particle. The results show that the temperature variation ofmodels have no relation with particle shape under the same process (same startingtemperature and same cooling way). From the perspective of the distribution and numerical value of equivalent stress, the combination face of particle and matrix has thephenomenon of stress concentration among three models. Sphere particle is helpful toreduce the phenomenon of stress concentration and bring down thermal stress. Becauseof the sharp interface between cylinder particle and matrix，so there is the phenomenonof stress concentration. Although the residual thermal in the Ellipsoid particle model isthe biggest, but the stress concentration is moderate than cylinder model.For another, this paper uses the model combining with the material microstructureand unit cell to analyze the influence of different particles distributions on the thermalresidual stress in the material under the same parameters compared with unit cell model.It turns out the phenomenon of stress concentration in the reunited model is obvious anduniform distribution of particles can reduce thermal residual stress concentrationphenomenon of composite，make the distribution of thermal stress homogeneous. Themodel of particles with gradient distribution reveals the phenomenon of gradientdistribution of thermal stress. So the material can get different properties on differentlayers corresponding to the density of particle.Furthermore, this thesis makes use of the ANSYS parametric design language to dothe secondary development of the program which is the procedure of the thermal stressanalysis of sphere model. By using the APDL language, we can set the physicalproperties of particles as the variable parameters and set the input of parameter in ainteractive way using the interface design command. By doing this development，userscan got the results that the influence of different sphere particles on the thermal residualstress of iron-matrix composites and this program also reduce the time and work inthermal stress analysis.