Microstructural factors controlling the strength and ductility of particle-reinforced metal-matrix composites (original) (raw)
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Failures analysis of particle reinforced metal matrix composites by microstructure based models
Materials & Design, 2010
This paper discusses the methodology of microstructure based elastic–plastic finite element analysis of particle reinforced metal matrix composites. This model is used to predict the failure of two dimensional microstructure models under tensile loading conditions. A literature survey indicates that the major failure mechanism of particle reinforced metal matrix composites such as particle fracture, interfaces decohesion and matrix yielding is mainly dominated by the distribution of particles in the matrix. Hence, analyses were carried out on the microstructure of random and clustered particles to determine its effect on strength and failure mechanisms. The finite element analysis models were generated in ANSYS, using scanning electron microscope images. The percentage of major failures and stress–strain responses were predicted numerically for each microstructure. It is evident from the analysis that the clustering nature of particles in the matrix dominates the failure modes of particle reinforced metal matrix composites.
Micromechanical modeling of reinforcement fracture in particle-reinforced metal-matrix composites
Metallurgical and Materials Transactions A, 1994
Finite element analyses of the effect of particle fracture on the tensile response of particle-reinforced metal-matrix composites are carried out. The analyses are based on twodimensional plane strain and axisymmetric unit cell models. The reinforcement is characterized as an isotropic elastic solid and the ductile matrix as an isotropically hardening viscoplastic solid. The reinforcement and matrix properties are taken to be those of an AI-3.5 wt pct Cu alloy reinforced with SiC particles. An initial crack, perpendicular to the tensile axis, is assumed to be present in the particles. Both stationary and quasi-statically growing cracks are analyzed. Resistance to crack growth in its initial plane and along the particle-matrix interface is modeled using a cohesive surface constitutive relation that allows for decohesion. Variations of crack size, shape, spatial distribution, and volume fraction of the particles and of the material and cohesive properties are explored. Conditions governing the onset of cracking within the particle, the evolution of field quantities as the crack advances within the particle to the particle-matrix interface, and the dependence of overall tensile stress-strain response during continued crack advance are analyzed.
Journal of Materials Processing Technology, 2008
This paper reports microstructure-based finite element analysis of particle-reinforced metal–matrix composite (PRMMC) to evaluate the stress–strain and failure behavior. The optimization of properties was carried out from analysis of microstructure of MMC since the properties depend on particles arrangement in microstructure. The microstructure with random particle arrangement and particle clusters were analysed. In order to model the microstructure for finite element analysis (FEA), the microstructures were converted into equivalent CAD file format. The FEA meshes were generated on the CAD model in ANSYS 7. The failures such as particle fracture, interface decohesion and matrix yielding were predicted for particle clustered and non-clustered microstructures. The effects of particles arrangement on the failure mechanisms were analysed.
Materials Science and Engineering: A, 2001
The correlation between macrohardness and tensile strength of particle reinforced metal matrix composites was studied. Contrary to monolithic metals, a simple relationship between hardness and tensile strength was not found. The reinforcement fraction and matrix strength appear to play an important role in influencing the behavior of the composite under hardness and tensile loading conditions. The different loading modes of the tensile test compared to the hardness test, along with the local increase in particle concentration directly underneath the indenter during indentation, result in a significant overestimation of the tensile strength by the hardness test, especially when the matrix strength is relatively low.
Acta Materialia, 2009
We present an enhanced continuum model for the size-dependent strengthening and failure of particle-reinforced composites. The model accounts explicitly for the enhanced strength in a discretely defined "punched zone" around the particle in a metal matrix composite as a result of geometrically necessary dislocations developed through a mismatch in the coefficients of thermal expansion. We incorporate the punched zone explicitly through a unit-cell model within this work, but the approach can be used more generally to account for discrete particle distributions and particle shapes. Smaller particles lead to greater strengthening, and this size effect is larger for larger volume fractions. An equation for the coupling of the size-dependent increase of yield strength of metal matrix composites with the particle volume fraction is obtained. The results indicate that the punched zone effect may amplify the occurrence of a variety of failure modes such as matrix localization, particle fracture and/or particle-matrix interface failure; smaller particles perceive higher stresses. We account for interface failure through a cohesive approach, and show that the interface damage mechanism is also particle-sizedependent. Some implications are presented for microstructural design of metal matrix composites.
Mechanical Behavior of Particle Reinforced Metal Matrix Composites
Advanced Engineering Materials, 2001
Metal matrix composites provide significantly enhanced properties Ð like higher strength, stiffness and weight savings Ð in comparison to conventional monolithic materials. Particle reinforced MMCs are attractive due to their cost-effectiveness, isotropic properties, and their ability to be processed using similar technology used for monolithic materials. This review captures the salient features of experimental as well as analytical and computational characterization of the mechanical behavior of MMCs. The main focus is on wrought particulate reinforced light alloy matrix systems, with a particular emphasis on tensile, creep, and fatigue behavior.
A three-dimensional realistic microstructure model of particle-reinforced metal matrix composites
Modelling and Simulation in Materials Science and Engineering, 2014
A new and robust methodology is presented for the complete computer simulation of large three-dimensional (3D) microstructures of particlereinforced metal matrix composites (PRMMCs), by integrating the boundary representation scheme, the random cutting algorithm and the random sequential adsorption algorithm. The methodology allows large realistic 3D microstructure models to be generated that can be used for multi-scale investigation of PRMMC structure and design. The effect of the simulation parameters on the simulated microstructure is investigated by applying a quantitative metallographic analysis of the distribution functions of aspect ratio, diameter and the area of reinforcements. Simulated large realistic homogenous 3D microstructures of PRMMC are in close agreement with the experimental microstructures.
Unit cells for micromechanical analyses of particle-reinforced composites
Mechanics of Materials, 2004
Unit cells are established in this paper for micromechanical analyses of particle-reinforced composites. A range of typical packing systems are examined in a systematic manner for each of them. Only the translational symmetry transformations are employed in establishing these unit cells. There are a number of important advantages resulting from this. The unit cells so derived are capable of dealing with problems involving reinforcing particles of irregular geometries and local imperfections such as debonding between the particles and the matrix, and microcracks in the matrix, provided the regularity of the packing and the orientation of the particles and the imperfections is maintained within the material. Furthermore, all the unit cells established can be subjected to arbitrary combinations of macroscopic stresses or strains using a single set of boundary conditions unlike most available unit cells in the literature, with which individual macroscopic stress or strain components may have to be analysed using different boundary conditions because of the use of reflectional symmetries. Boundary conditions for the unit cells proposed in this paper are derived from appropriate considerations of the conditions resulting from translational symmetry transformations. Applications of loads in terms of macroscopic stresses or strains and thermal loading to the unit cells are described in such a way that they can be implemented in a straightforward manner and the effective properties of composites can be evaluated following a standard and simple procedure without a numerical averaging process. The implementation of the unit cells in the micromechanical finite element analysis of particle-reinforced composites has been demonstrated fully. Spherical particles are assumed and both the particle and the matrix are assumed to be linear elastic materials and the bonding between the particle and the matrix to be perfect. 3D brick elements have been employed to generate the meshes for analysing the unit cells corresponding to various packing systems. The effective properties of the composite represented by the unit cells have been obtained through the analyses and they have been discussed and compared with results in the literature. Stress distributions in the particle and surrounding matrix have been examined. Some interesting characteristics of the different packing systems have been elaborated.
Finite element micromechanical modelling of yield and collapse behaviour of metal matrix composites
Journal of the Mechanics and Physics of Solids, 2000
The initial yield and collapse behaviour of ®bre reinforced metal matrix composites (MMCs) have been investigated using ®nite element micro-mechanical models. Initial yield occurs as the loading on the MMC is increased until the most heavily loaded point within the matrix reaches the yield stress. Collapse occurs when the MMC is unable to support a higher load. The results of this work show that loads to cause collapse of MMCs are higher than those to cause ®rst yield, particularly when the eect of residual stress arising from manufacture is included in the analysis. Initial yield and collapse envelopes have been generated for a Silicon Carbide-Titanium MMC for biaxial and shear loading. These envelopes include the eect of residual stress and also various interface conditions between the ®bre and matrix: either perfectly bonded or de-bonded, with and without friction. An analytical micro-mechanical model has been developed using the method of cells to predict the collapse behaviour. The results of the analytical model compare reasonably well with those of the ®nite element method. Using the analytical model the eect of varying the ®bre volume fraction on the collapse behaviour has been studied.