Determination of Thermally and Mechanically Induced Internal Stresses in Metal-Matrix Composites by X-Ray Methods

1988 ◽  
Vol 142 ◽  
Author(s):  
Rahmi Yazici ◽  
K. E. Bagnoli ◽  
Y. Bae
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Internal Stresses ◽  
Matrix Composites ◽  
Thermally Induced ◽  
X Ray ◽  
The Matrix ◽  
Stress States ◽  
Individual Grains ◽  
Ray Methods

AbstractIn this study the progression of thermally and mechanically induced internal strains (stresses) in metal-matrix composites was investigated by X-ray methods. The materials studied were whisker-reinforced 2124 Al-SiC(w) and 6061 Al- SiC(w) composites. X-ray diffractometry was used to measure thermally induced stresses on samples cycled from ambient to 280°C. Significant variations in residual stress values were observed in the matrix depending on the location and direction of the measurements with respect to the whisker orientation. The determined stress states of the as-processed and the thermally cycled samples were evaluated with continuum models. The microstrains in composites induced during processing and tensile loading were also investigated by nondestructive means. Individual grains of the matrix were analyzed by rocking-curve measurements using a modified X-ray doublecrystal diffractometer. The relationship between the plastic deformation induced by applied loads and the progression of the microstrain/excess-dislocation values was determined.

Thermally induced dislocation generation in Al/Al2O3 metal-matrix composites

1991 ◽  
Vol 49 ◽  
pp. 588-589
Author(s):  
Kenneth S. Vecchio
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Internal Stresses ◽  
Frictional Stress ◽  
Matrix Composites ◽  
Matrix Interface ◽  
Dislocation Loops ◽  
Thermally Induced ◽  
The Matrix ◽  
Induced Dislocation

It has been well documented that when a large difference in the coefficients of thermal expansion (CTE) exist between the matrix and reinforcement in metal-matrix composites (MMCs) internal stresses can develop which are sufficiently high to generate dislocations at the reinforcement/matrix interface. Numerous observations have been made of this phenomenon via TEM which have shown a variety of different dislocation substructures and dislocation punching mechanisms. An important consequence of this phenomenon is that the metal matrix becomes strain hardened as the dislocation density increases, thereby reducing subsequent plastic flow of the matrix. One notable feature of the dislocation punching mechanism is that prismatic dislocation loops are commonly observed emanating from the interface. In two recent studies it was found that dislocations were not emitted immediately upon cooling, but rather at some lower critical temperature. A number of microstructural and processing parameters can affect the thermally-induced dislocation substructure such as: a) differences in CTEs, b) lattice frictional stress, c) vol.% particulate, d) particle/matrix interface morphology, e) quench temperatures (ΔT effect), and f) thermal-cycling (e.g. reheating and requenching).

scholarly journals Predictive Computational Model for Damage Behavior of Metal-Matrix Composites Emphasizing the Effect of Particle Size and Volume Fraction

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2143
Author(s):  
Shaimaa I. Gad ◽  
Mohamed A. Attia ◽  
Mohamed A. Hassan ◽  
Ahmed G. El-Shafei
Keyword(s):  
Finite Element ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Volume Fraction ◽  
Particulate Composites ◽  
Aluminum Matrix Composites ◽  
Matrix Composites ◽  
Zone Method ◽  
Stress Strain ◽  
The Matrix

In this paper, an integrated numerical model is proposed to investigate the effects of particulate size and volume fraction on the deformation, damage, and failure behaviors of particulate-reinforced metal matrix composites (PRMMCs). In the framework of a random microstructure-based finite element modelling, the plastic deformation and ductile cracking of the matrix are, respectively, modelled using Johnson–Cook constitutive relation and Johnson–Cook ductile fracture model. The matrix-particle interface decohesion is simulated by employing the surface-based-cohesive zone method, while the particulate fracture is manipulated by the elastic–brittle cracking model, in which the damage evolution criterion depends on the fracture energy cracking criterion. A 2D nonlinear finite element model was developed using ABAQUS/Explicit commercial program for modelling and analyzing damage mechanisms of silicon carbide reinforced aluminum matrix composites. The predicted results have shown a good agreement with the experimental data in the forms of true stress–strain curves and failure shape. Unlike the existing models, the influence of the volume fraction and size of SiC particles on the deformation, damage mechanism, failure consequences, and stress–strain curve of A359/SiC particulate composites is investigated accounting for the different possible modes of failure simultaneously.

scholarly journals Interfacial Aspects of Metal Matrix Composites Prepared from Liquid Metals and Aqueous Solutions: A Review

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1400
Author(s):  
Peter Baumli
Keyword(s):  
Aqueous Solutions ◽  
Physical Properties ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Liquid Metals ◽  
Interfacial Phenomena ◽  
Matrix Composites ◽  
Good Adhesion ◽  
Mechanical And Physical Properties ◽  
The Matrix

The paper reviews the preparation of the different metallic nanocomposites. In the preparation of composites, especially in the case of nanocomposites, interfacial phenomena play an important role. This review summarizes the literature on various interfacial phenomena, such as wettability and reactivity in the case of casting techniques and colloidal behavior in the case of electrochemical and electroless methods. The main contribution of this work lies in the evaluation of collected interfacial phenomena and difficulties in the production of metal matrix composites, for both nano-sized and micro-sized reinforcements. This study can guide the composite maker in choosing the best criteria for producing metal matrix composites, which means a real interface with good adhesion between the matrix and the reinforcement. This criterion results in desirable mechanical and physical properties and homogenous dispersion of the reinforcement in the matrix.

Creep Deformation of Particle-Strengthened Metal-Matrix Composites

1989 ◽  
Vol 111 (1) ◽  
pp. 99-105 ◽  
Author(s):  
Z. G. Zhu ◽  
G. J. Weng
Keyword(s):  
Constitutive Equation ◽  
Metal Matrix Composites ◽  
Creep Strain ◽  
Creep Deformation ◽  
Creep Resistance ◽  
Metal Matrix ◽  
Order Approximation ◽  
Stress Redistribution ◽  
Matrix Composites ◽  
The Matrix

A multiaxial theory of creep deformation for particle-strengthened metal-matrix composites is derived. This derivation is based on the observation that there are two major sources of creep resistance in such a system. The first, or metallurgical effect, arises from the increased difficulty of dislocation motion in the presence of particles and is accounted for by a size- and concentration dependent constitutive equation for the matrix. The second, or mechanics effect, is due to the continuous transfer of stress from the ductile matrix to the hard particles and the corresponding stress redistribution is also incorporated in the derivation. Both power-law creep and exponential creep in the matrix, each involving the transient as well as the steady state, are considered. The constitutive equations thus derived can provide the development of creep strain of the composite under a combined stress. The multiaxial theory is also simplified to a uniaxial one, whose explicit stress-creep strain-time relations at a given concentration of particles are also given by a first- and second-order approximation. The uniaxial theory is used to predict the creep deformation of an oxide-strengthened cobalt, and the results are in reasonably good agreement with the experiment. Finally, it is demonstrated that a simple metallurgical approach without considering the stress redistribution between the two constituent phases, or a simple mechanics approach without using a modified constitutive equation for the metal matrix, may each underestimate the creep resistance of the composite, and, therefore, it is important that both factors be considered in the formulation of such a theory.

Transmission Electron Microscope Specimen Preparation of Metal Matrix Composites Using the Focused Ion Beam Miller

2000 ◽  
Vol 6 (5) ◽  
pp. 452-462 ◽  
Author(s):  
Julie M. Cairney ◽  
Robert D. Smith ◽  
Paul R. Munroe
Keyword(s):  
Electron Microscope ◽  
Metal Matrix Composites ◽  
Transmission Electron Microscope ◽  
Metal Matrix ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Matrix Composites ◽  
Transmission Electron ◽  
The Matrix ◽  
Ceramic Reinforcement

AbstractTransmission electron microscope samples of two types of metal matrix composites were prepared using both traditional thinning methods and the more novel focused ion beam miller. Electropolishing methods were able to produce, very rapidly, thin foils where the matrix was electron transparent, but the ceramic reinforcement particles remained unthinned. Thus, it was not possible in these foils to study either the matrix-reinforcement interface or the microstructure of the reinforcement particles themselves. In contrast, both phases in the composites prepared using the focused ion beam miller thinned uniformly. The interfaces in these materials were clearly visible and the ceramic reinforcement was electron transparent. However, microstructural artifacts associated with ion beam damage were also observed. The extent of these artifacts and methods of minimizing their effect were dependent on both the materials and the milling conditions used.

X-ray welding of metal-matrix composites

1997 ◽  
Vol 68 (6) ◽  
pp. 2550-2553 ◽  
Author(s):  
Richard A. Rosenberg ◽  
Qing Ma ◽  
William Farrell ◽  
Mark Keefe ◽  
Derrick C. Mancini
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Matrix Composites ◽  
X Ray

Multiscale Analysis of Structures Composed of Metal Matrix Composites Considering Phase Debonding

2017 ◽  
Vol 08 (03n04) ◽  
pp. 1740004 ◽  
Author(s):  
G. R. Fernandes ◽  
A. S. Furtado ◽  
J. J. C. Pituba ◽  
E. A. De Souza Neto
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Multiscale Analysis ◽  
Matrix Composites ◽  
Tensor Fields ◽  
Interface Zone ◽  
The Matrix ◽  
Von Mises ◽  
Cohesive Fracture Model ◽  
Element Method

Multiscale analyses considering the stretching problem in plates composed of metal matrix composites (MMC) have been performed using a coupled BEM/FEM model, where the boundary element method (BEM) and the finite element method (FEM) models, respectively, the macrocontinuum and the material microstructure, denoted as representative volume element (RVE). The RVE matrix zone behavior is governed by the von Mises elasto-plastic model while elastic inclusions have been incorporated to the matrix to improve the material mechanical properties. To simulate the microcracks evolution at the interface zone surrounding the inclusions, a modified cohesive fracture model has been adopted, where the interface zone is modeled by means of cohesive contact finite elements to capture the effects of phase debonding. Thus, this paper investigates how this phase debonding affects the microstructure mechanical behavior and consequently affects the macrostructure response in a multiscale analysis. For that, initially, only RVEs subjected to a generic strain are analyzed. Then, multiscale analyses of plates have been performed being each macro point represented by a RVE where the macro-strain must be imposed to solve its equilibrium problem and obtain the macroscopic constitutive response given by the homogenized values of stress and constitutive tensor fields over the RVE.

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