scholarly journals Why Al-B4C Metal Matrix Composites? A Review

2021 ◽  
Author(s):  
Mohamed F. Ibrahim ◽  
Hany R. Ammar ◽  
Agnes M. Samuel ◽  
Mahmoud S. Soliman ◽  
Victor Songmene ◽  
...  

The Al-B4C metal matrix composite (MMC) is characterized by its ability to absorb neutrons which makes it the most suitable shielding material for nuclear reactors. The present work was performed on two series of Al-B4C metal matrix composites made using a powder injection apparatus. In one series, commercially pure aluminum (A5) served as the matrix. For the second set, 6063 alloy was used. In all cases the volume fraction of B4C reinforcement particles (grit size 400 mesh, purity 99.5%) was approximately 15%. The volume fraction of the injected B4C particles was determined using a computer driven image analyzer. Measured amounts of Ti, Zr, and Ti + Zr, were added to the molten composites of both series. Microstructural characterization was carried out employing a field emission scanning electron microscope operating at 20 kV and equipped with an electron dispersive x-ray spectroscopic system (EDS). The same technique was applied to characterize the fracture behavior of the tested composites. Mechanical properties of these composites were investigated using impact testing, and ambient and high temperature tensile testing methods. Almost 1000 impact and tensile samples were tested following different heat treatments. The obtained results from these investigations are reported in this Chapter.

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2143
Author(s):  
Shaimaa I. Gad ◽  
Mohamed A. Attia ◽  
Mohamed A. Hassan ◽  
Ahmed G. El-Shafei

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.


2012 ◽  
Vol 710 ◽  
pp. 365-370 ◽  
Author(s):  
Sujayakumar Prasanth ◽  
Kumaraswamy Kaliamma Ajith Kumar ◽  
Thazhavilai Ponnu Deva Rajan ◽  
Uma Thanu Subramonia Pillai ◽  
Bellambettu Chandrasekhara Pai

Magnesium metal matrix composites (MMCs) have been receiving attention in recent years as an attractive choice for aerospace and automotive applications because of their low density and superior specific properties. Using stir casting process, AZ91 magnesium alloy metal matrix composites have been produced with different weight percentages (5, 10, 15, 20 and 25) of silicon carbide particles (SiCp) addition. Microstructural characterization reveals uniform distribution of SiC particles with good interfacial bonding between the matrix and reinforcement. Electrical conductivity and Co-efficient of Thermal Expansion (CTE) measurements carried out on these composites have yielded better properties. Improved mechanical properties such as hardness, ultimate tensile strength, and compressive strength are obtained. The microfracture mechanisms involved during tensile fracture is analyzed and correlated with the properties obtained.


1994 ◽  
Vol 350 ◽  
Author(s):  
D. B. Miracle ◽  
P. R. Smith ◽  
J. A. Graves

AbstractA significant materials-based activity to develop Ti-aluminide metal matrix composites for high temperature aerospace structural applications is now underway. A review of the approaches, progress, and status of the development of continuously-reinforced Ti-aluminide metal matrix composites with matrices which contain a significant volume fraction of the ordered orthorhombic Ti2AlNb phase will be presented. The principal application considered is a gas turbine compressor rotor ring, and this influences the development approaches and properties goals. Specific development activity that will be presented includes modification and control of the matrix composition and microstructure, fiber coating treatments to control interdiffusion between the fiber and the matrix, and to improve the ability of the interface to support a mechanical load, and efforts to improve the properties of SiC monofilaments used as reinforcements. Critical issues that define the requirements for additional studies will be presented.


Author(s):  
P. K. Wright

Metal matrix composites (MMC) are expected to develop internal residual stresses on cooling from fabrication due to the large thermal expansion mismatch between reinforcing fibers and the matrix. This work was undertaken to experimentally measure these residual stresses and compare them with analytical calculations in order to clearly establish their levels and dependence on material parameters. Two techniques for residual stress measurement were investigated: 1) Xray diffraction (sin2 psi method) and 2) neutron diffraction. Both techniques gave results in good agreement with analytical predictions for several systems (SCS-6/Ti-24Al-11Nb, W/NiAl, and Al2O3NiAl). The results obtained showed a dependence of residual stresses on thermal expansion coefficients, elastic moduli, volume fraction fibers, and matrix yield strengths. The fibers showed compressive stress states, and the matrix, tension. Average stresses were higher in the fiber direction than transverse to fibers.


1994 ◽  
Vol 116 (3) ◽  
pp. 605-610 ◽  
Author(s):  
P. K. Wright

Metal matrix composites (MMC) are expected to develop internal residual stresses on cooling from fabrication due to the large thermal expansion mismatch between reinforcing fibers and the matrix. This work was undertaken to measure experimentally these residual stresses and compare them with analytical calculations in order to establish clearly their levels and dependence on material parameters. Two techniques for residual stress measurement were investigated: (1) X-ray diffraction (sin2-psi method) and (2) neutron diffraction. Both techniques gave results in good agreement with analytical predictions for several systems (SCS-6/Ti-24Al-11Nb, W/NiAl, and Al2O3NiAl). The results obtained showed a dependence of residual stresses on thermal expansion coefficients, elastic moduli, volume fraction fibers, and matrix yield strengths. The fibers showed compressive stress states, and the matrix, tension. Average stresses were higher in the fiber direction than transverse to fibers.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Krishna Mohan Singh ◽  
Akhilesh Kumar Chauhan

The aim of this research paper is to find the wear behaviour of Al7075 MMCs. In this investigation, the wear tests on the as-cast and age-hardened specimens were performed on an advanced rotary tribometer. The materials selected for the analysis are Al7075 as a matrix, and the reinforcements are boron carbide. By using stir casting, metal matrix composites are manufactured by adding B4C as a reinforcement particulate in Al7075. The fabricated composites were characterized and the wear behaviour of these composites was carried out on an advanced rotary tribometer. The wt. % of the reinforcements was taken as 6%, 8%, 10%, and 12%. The almost homogeneous blending of reinforcements is shown by the microstructural characterization of Al7075 MMCs. It is observed that due to the rise in weight percentage of the reinforcement to 12% higher hardness is obtained. For 12% of reinforcements, there is an increase in hardness due to the heat treatment than that of the as-cast composites. From this study, it was found that the wear rate is the function of the applied load, microstructure, and volume fraction of the reinforcements. The wear rate was increasing with the sliding velocity.


Author(s):  
M. G. Burke ◽  
M. N. Gungor ◽  
P. K. Liaw

Aluminum-based metal matrix composites offer unique combinations of high specific strength and high stiffness. The improvement in strength and stiffness is related to the particulate reinforcement and the particular matrix alloy chosen. In this way, the metal matrix composite can be tailored for specific materials applications. The microstructural characterization of metal matrix composites is thus important in the development of these materials. In this study, the structure of a p/m 2014-SiC particulate metal matrix composite has been examined after extrusion and tensile deformation.Thin-foil specimens of the 2014-20 vol.% SiCp metal matrix composite were prepared by dimpling to approximately 35 μm prior to ion-milling using a Gatan Dual Ion Mill equipped with a cold stage. These samples were then examined in a Philips 400T TEM/STEM operated at 120 kV. Two material conditions were evaluated: after extrusion (80:1); and after tensile deformation at 250°C.


Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1400
Author(s):  
Peter Baumli

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.


1989 ◽  
Vol 111 (1) ◽  
pp. 99-105 ◽  
Author(s):  
Z. G. Zhu ◽  
G. J. Weng

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.


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