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Showing papers on "Metal matrix composite published in 1996"


Patent
02 May 1996
TL;DR: An improved metal matrix composite utilizes boron carbide as a ceramic additive to a base material metal as mentioned in this paper, which is useful in a variety of applications where lightweight, strength, stiffness, hardness, and low density are desirable.
Abstract: An improved metal matrix composite utilizes boron carbide as a ceramic additive to a base material metal. The base material metal is aluminum, magnesium, or titanium, or an alloy thereof, provided in powder form with the balance of the material comprising various trace metals such as chromium, copper, iron, magnesium, silicon, titanium, and zinc. The boron carbide powder comprises 10 to 30% by weight of the metal matrix composition. There is at least one other metal additive. The compositions are useful in a variety of applications where lightweight, strength, stiffness, hardness, and low density are desirable. The compositions are extrudable and weldable.

106 citations


Journal ArticleDOI
TL;DR: In this paper, the machinability of Al2O3 composites reinforced with SiC or Al 2O3 particles was investigated. Butts et al. used models for cumulative tool wear to study the machINability of aluminium matrix composites.

72 citations


Patent
28 Oct 1996
TL;DR: In this paper, a liquid cooled power dissipation apparatus (10) includes a metal matrix composite heat sink (11) with an insulation layer (17) integral to the apparatus, and the insulation layer is made integral during infiltration of the metal matrix composites heat sink.
Abstract: A liquid cooled power dissipation apparatus (10) includes a metal matrix composite heat sink (11) with an insulation layer (17) integral to the apparatus (10). The insulation layer (17) is made integral to the apparatus (10) during infiltration of the metal matrix composite heat sink (11). Electronic components 23 are situated on top of the insulation layer (17).

66 citations


Journal ArticleDOI
TL;DR: In this article, the influence of the metal/ceramic interface on the microstructure and mechanical properties of iron-based composites with a high-chromium white iron matrix has been investigated.

66 citations


Journal ArticleDOI
TL;DR: In this article, the wear behavior of metal-matrix composites (MMCs) and that of the monolithic Al/12 wt% Si alloy was investigated in pin-on-disk tests from room temperature to 400 °C under dry conditions.

63 citations


Journal ArticleDOI
TL;DR: An analytical elasto-plastic stress analysis for a metal-matrix composite beam of arbitrary orientation subjected to a single transverse force applied to the free end of the beam and a uniformly distributed load is presented in this paper.

62 citations


Journal ArticleDOI
TL;DR: In this article, the internal mismatch between the transforming matrix and the non-transforming particulates was modeled by considering the internal superplastic strain, resulting in an increase in the strain to fracture.

58 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of prestraining on the coefficient of thermal expansion (CTE) of 10 and 20 volume percent (v/o) Al2O3 particle-reinforced composite over various temperature ranges using thermal mechanical analysis (TMA).

58 citations


Journal ArticleDOI
TL;DR: In this paper, the effects of process parameters on the properties of squeeze-cast high reinforcement volume-fraction SiCp-6061 Al metal matrix composite (MMC) have been examined.
Abstract: The effects of process parameters on the properties of squeeze-cast high reinforcement volume-fraction SiCp-6061 Al metal matrix composite (MMC) have been examined. The process parameters included cooling rate, reinforcement particle size, addition of silica binder, and solution treatment temperature. The properties studied were flexure strength, microstructure, variation of hardness, solute content gradient, and aging behavior. It was found that water cooling improved the flexure strength and hardness of MMC significantly when compared with furnace-cooled MMC. For the same volume fraction of reinforcement, lowering the average particle size from 85 to 14 μm increased the flexure strength and hardness of the MMC greatly. A solution treatment temperature very close to the eutectic point was found to improve the strength. Mechanisms leading to the above-mentioned effects and suggestions are discussed.

54 citations


Journal ArticleDOI
TL;DR: In this paper, a model for the sliding friction of multiphase materials in abrasion is presented, where the friction is described in terms of the load distribution between the phases, and different load distribution modes are used with Amontons' first law of friction to derive both the friction force and the coefficient of friction as functions of the area fractions of the phases.

47 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of high temperatures on the quality of the interface has been investigated and it seems that an MMC based on Cu/SiC alloyed with Fe can be exposed in use to the temperature range 870-1135 K.
Abstract: Metal matrix composites (MMCs) of Cu/SiC can be produced directly by hot isostatic pressing (HIP) by eliminating the reaction at the fibre-matrix interface via small additions of Fe. No further heat treatment is required if the HIP is performed at about 925 K for approximately 7.2 × 103 s at a pressure of 100 MPa. The interface resulting from the application of the processing technique is almost perfect. Without Fe addition a reaction at the fibre-matrix interface was observed, despite the high temperatures and extended times used. The effect of high temperatures on the quality of the interface has been investigated and it seems that an MMC based on Cu/SiC alloyed with Fe can be exposed in use to the temperature range 870–1135 K. Exposure of the Cu/Fe/SiC composite for extended times at 1135 K or above is detrimental because of interface reactions.

Journal ArticleDOI
TL;DR: In this paper, the influence of the matrix structure on the mechanical properties of a hot isostatic pressed (hipped) white iron matrix composite containing 10 vol pct TiC is investigated.
Abstract: The influence of the matrix structure on the mechanical properties of a hot isostatic pressed (hipped) white iron matrix composite containing 10 vol pct TiC is investigated. The matrix structure was systematically varied by heat treating at different austenitizing temperatures. Various subsequent treatments were also employed. It was found that an austenitizing treatment at higher temperatures increases the hardness, wear resistance, and impact toughness of the composite. Although after every different heat treatment procedure the matrix structure of the composite was predominantly martensitic, with very low contents of retained austenite, some other microstructural features affected the mechanical properties to a great extent. Abrasion resistance and hardness increased with the austenitizing temperature because of the higher carbon content in martensite in the structure of the composite. Optimum impact energy values were obtained with structures containing a low amount of M (M7C3+M23C6) carbides in combination with a decreased carbon content martensite. Structure austenitized at higher temperatures showed the best tempering response. A refrigerating treatment was proven beneficial after austenitizing the composite at the lower temperature. The greatest portion in the increased martensitic transformation in comparison to the unreinforced alloy, which was observed particularly after austenitizing the composite at higher temperatures,[1] was confirmed to be mechanically induced. The tempering cycle might have caused some additional chemically induced transformation. The newly examined iron-based composite was found to have higher wear resistance than the most abrasion-resistant ferroalloy material (white cast iron).

Patent
13 May 1996
TL;DR: In this article, a method of fabricating a metal matrix composite (MMC) containing electrically isolated areas is described. But the method is not suitable for the fabrication of complex structures.
Abstract: A method of fabricating a metal matrix composite (30) containing electrically isolated areas (34, 36, 38) and the MMC (30) formed from the method. The method comprises: (a) providing a liquid pool of unreinforced aluminum alloy; (b) infiltrating the unreinforced aluminum alloy (46) into a stack comprising upper and lower porous preforms and an electrical insulator material (42) placed between the preforms; (c) solidiying the liquid-phase metal to form a metal matrix composite product that completely surrounds the stack; and (d) forming at least one groove in the solidified metal, the groove extending downward to the insulating substrate so as to electrically isolate at least one region on the surface of the metal matrix composite.

Journal ArticleDOI
TL;DR: In this paper, a cyclic plasticity model was proposed to model the behavior of directionally reinforced metal matrix composite, which can model different initial yielding behavior along different stress directions.

Journal ArticleDOI
TL;DR: In this paper, the authors presented the pulsed laser cutting behavior of an Al-Li/SiC metal matrix composite and proposed a theoretical model to predict the maximum depth-of-cut for the composite.
Abstract: This paper presents the pulsed laser cutting behavior of an Al-Li/SiC metal matrix composite. SEM and EDX examinations were conducted to study the influences of laser cutting parameters on the quality of the machined surface. Through proper process control it was found possible to minimize the heat affected zone (HAZ) and to improve the quality of the machined surface. An empirical formula relating the width of the HAZ and the laser cutting parameters was proposed. Furthermore, a theoretical model has been successfully applied to predict the maximum depth-of-cut for the composite. Finally, the optimum condition for achieving high cutting efficiency with minimum material damage was recommended.

Journal ArticleDOI
TL;DR: In this article, metal matrix composite layer formation by means of laser alloying using 6 μm particle size SiC powder (SiCp) preplaced on titanium surfaces in a nitrogen environment produced golden coloured tracks and a complete solution of SiCp in the melt zones under a range of processing conditions.
Abstract: Metal matrix composite layer formation by means of laser alloying using 6 μm particle size SiC powder (SiCp) preplaced on titanium surfaces in a nitrogen environment produced golden coloured tracks and a complete solution of SiCp in the melt zones under a range of processing conditions. The melt layers consisted of dendrites at the top (titanium nitride based) followed by threadlike particle structures (titanium silicides), and the sizes of dendrites and the threadlike particles werefound to increase with increasing laser power density. The surface layer of the dendrites developed a hardness 4·5–9 times that of the base metal (150 HV), and the deep underlying threadlike structures had a plateau of hardness of aboout 2·8–4 times the base hardness. The metal matrix composite layers were found to be 2–4 times thicker than those produced previously in a helium environment under similar processing conditions. The exothermic reactions due to the formation of titanium nitride, titanium carbide, or titani...

Patent
Gerald A. Gegel1
29 Feb 1996
TL;DR: A ground engaging tool for an earthworking machine comprises a ground engaging element with a cast-in-place metal matrix composite component as mentioned in this paper, which consists of a preform having interconnecting porosity.
Abstract: A ground engaging tool for an earthworking machine comprises a ground engaging element with a cast-in-place metal matrix composite component. The ground engaging element comprises a metal base component and a metal matrix composite component. The metal matrix component is bonded to the metal base component. The metal matrix composite component consists of a preform having interconnecting porosity. The preform is formed from a material selected from one of ceramic, cermet, or mixtures thereof. The metal matrix composite component also consists of an infiltration metal. The preform is infiltrated by the infiltration metal and the infiltration metal is fusion bonded to the metal base component.

Journal ArticleDOI
TL;DR: An integrated approach, involving laboratory experiments, extrusion plant trials, and finite element modeling (FEM) has been adopted for the study of the extrusion of the metal matrix composite (MMC) 6061/Al2O3/20p.
Abstract: An integrated approach, involving laboratory experiments, extrusion plant trials, and finite element modeling (FEM) has been adopted for the study of the extrusion of the metal matrix composite (MMC) 6061/Al2O3/20p. Gleeble compression tests were performed to develop the constitutive equation of the MMC under industrial extrusion process conditions. Extrusion plant trials were conducted to measure load and temperature and to obtain samples for microstructural analysis. Metal flow, with respect to particle behavior in the deformation zone, was examined microscopically. An FEM based on the commercial code DEFORM was adopted for the simulation of the extrusion of the MMC; the constitutive equation developed was incorporated into the model. Using an updated Lagrangian formulation, both the transient and steady-state regions of extrusion were modeled. Load and temperature predictions resulting from this model agree well with the measured values in the upsetting stage and in the steady-state region. Temperature predictions agree to within less than 3 pct of the measured values. The FEM predictions of temperature, stress, strain, and strain-rate distribution were correlated with the particle behavior and low-speed cracking during extrusion: large shear deformation promotes particle fracture in the deformation zone, and tensile stress generation in the die land zone of the billet leads to low-speed cracking of the MMC during extrusion. The latter occurs at low temperature in the front end of the billet at the beginning of the extrusion process due to heat loss to the cold die.

Journal ArticleDOI
TL;DR: In this article, the cumulative wear of a cutting tool does not depend on the order of different cutting speeds since abrasive wear dominates the wear mechanism, and it is more economical to rank machinability using data for facing, and to convert them for turning if required.

Journal ArticleDOI
TL;DR: In this paper, the deformation microstructure of a fiber reinforced in situ metal matrix composite (MMC) consisting of Cu and 20mass% Nb was studied by the use of optical and electron microscopy.

Journal ArticleDOI
TL;DR: In this paper, the microstructural evolution of a Cu-15wt.% in situ metal matrix composite has been investigated by means of scanning electron microscopy, analytical transmission electron microscope, high resolution electron microscope and energy-dispersive X-ray spectrometry.
Abstract: The microstructural evolution of a Cu-15wt.%Cr in situ metal matrix composite has been investigated by means of scanning electron microscopy, analytical transmission electron microscopy, high resolution electron microscopy and energy-dispersive X-ray spectrometry. It is found that the dendritic Cr and equiaxed Cr in the as-cast state are mostly deformed into Cr ribbons after cold rolling to 89.8% reduction in thickness. In these heavily deformed Cr ribbons, ellipsoidal Cu-rich clusters with size around 1 nm were observed which have the same lattice as the Cr ribbons but different Cu concentrations from each other. Lattice distortion also exists around these Cu-rich clusters, though its extent varies depending on the Cu concentration in each cluster.

Journal ArticleDOI
TL;DR: In this article, the role of silicon carbide in microgalvanic corrosion of magnesium-based metal matrix composites (MMCs) was investigated, and a high-purity MMC was specially prepared by magnetron sputtering magnesium on to a substrate surface impregnated with silicon carbides particles.

Patent
19 Jan 1996
TL;DR: A metal matrix composite is made by assembling pre-forms of porous reinforcing material with an array of separator plates in a die in a pressure vessel, and infiltrating molten metal matrix material as mentioned in this paper.
Abstract: Metal matrix composite is made by assembling pre-forms of porous reinforcing material with an array of separator plates in a die in a pressure vessel, and infiltrating molten metal matrix material Pre-evacuation followed by pressurisation when the molten metal matrix material is introduced into the die aids the infiltration Re-introduction of gas during initial heating prior to melting speeds the heat-up process

Journal ArticleDOI
TL;DR: In this article, an exact elastic-plastic analytical solution for an arbitrarily laminated metal matrix composite tube subjected to axisymmetric thermo-mechanical and torsional loading is presented.
Abstract: An exact elastic-plastic analytical solution for an arbitrarily laminated metal matrix composite tube subjected to axisymmetric thermo-mechanical and torsional loading is presented. First, exact solutions for transversely isotropic and monoclinic (off-axis) elastoplastic cylindrical shells are developed which are then reformulated in terms of the interfacial displacements as the fundamental unknowns by constructing a local stiffness matrix for the shell. Assembly of the local stiffness matrices into a global stiffness matrix in a particular manner ensures satisfaction of interfacial traction and displacement continuity conditions, as well as the external boundary conditions. Due to the lack of a general macroscopic constitutive theory for the elastic-plastic response of unidirectional metal matrix composites, the micromechanics method of cells model is employed to calculate the effective elastic-plastic properties of the individual layers used in determining the elements of the local and thus global stiffness matrices. The resulting system of equations is then solved using Mendelson`s iterative method of successive elastic solutions developed for elastoplastic boundary-value problems. Part 1 of the paper outlines the aforementioned solution strategy. In Part 2 (Salzar et al., 1996), this solution strategy is first validated by comparison with available closed-form solutions, as well as with results obtained using the finite-element approach.more » Subsequently, examples are presented that illustrate the utility of the developed solution methodology in predicting the elastic-plastic response of arbitrarily laminated metal matrix composite tubes. In particular, optimization of the response of composite tubes under internal pressure is considered through the use of functionally graded architectures.« less

Journal ArticleDOI
TL;DR: In this article, the authors investigated the basic influences of SiC particulate and Al2O3 fiber on the formation of an MMC layer by laser processing, and it is believed that the discussions in the present work will be applicable for a wider use of this laser process.

Journal ArticleDOI
01 Jun 1996-JOM
TL;DR: In this paper, the vacuum-plasma-spraying technique was used to produce aluminum-matrix composites with a low coefficient of thermal expansion reinforced with fine ceramic particles, resulting in a uniform particle dispersion and bulk porosity of less than 1.5%.
Abstract: The vacuum-plasma-spraying technique presented in this article is suited to produce aluminum-matrix composites with a low coefficient of thermal expansion reinforced with fine ceramic particles, resulting in a uniform particle dispersion and bulk porosity of less than 1.5% in the as-sprayed condition. Plastic deformation of the plates followed by annealing resulted in significant increases in ultimate tensile strength, hardness, and elongation.

Journal ArticleDOI
TL;DR: In this article, the densification process was studied in an iron-based composite reinforced with fine TiC particles and the results revealed that the presence of a high amount of rigid-rigid contacts and the formation of ceramic particle networks within the composite powder mixture increase the pressure required for densification.

Journal ArticleDOI
TL;DR: In this article, the authors investigated overlapping laser tracks using prep laced SiC p and a mixture of SiCp and aluminium powder preplaced on AA6061 aluminium alloy surfaces, and described the success achieved in both situations.
Abstract: Although metal matrix composite (MMC) layers have been successfully produced by a single laser track on aluminium alloys, a critical step in the application of this technique in industry is overlapping of the laser tracks to produce an MMC layer on specific areas of materials. The present work investigated overlapping laser tracks using prep laced SiC p and a mixture of SiCp and aluminium powder preplaced on AA6061 aluminium alloy surfaces, and describes the success achieved in both situations. The dependence of the surface smoothness on the overlapping technique, microstructures, and phases formed in the laser processing was studied. The effect of the spacing of two overlapped laser tracks is discussed and the laser processing conditions considered. In addition, post heat treatment on the laser glazed material was found to give rise to a significant increase in the hardness and the abrasive wear resistance of the MMC layer.MST/3236

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the evolution of damage in a SiC-reinforced 2618 AI alloy during plastic strain by elastic modulus reduction and direct observations of the microstructure at room temperature and temperatures up to 220 °C.
Abstract: The evolution of damage in a SiC-reinforced 2618 AI alloy during plastic strain has been investigated by elastic modulus reduction and direct observations of the microstructure at room temperature and temperatures up to 220 °C. Particle fracture increases as a function of strain at all temperatures but the total number of fractured particles at any given strain is lower at higher test temperatures. The dependence of fracture on particle size and aspect ratio was recorded. Normalized elastic modulus measurements decrease as a function of strain at the same rate for tests at 25,110 and 220 °C with an anomalous set of measurements at 165 °C showing a reduced damage rate. There is no universal correlation between the number of damaged particles and reduced modulus with each test temperature showing a different relation. This indicates the different temperature dependence of void nucleation and subsequent growth. The results are used to interpret different models of load sharing between reinforcement and matrix during straining.[/p]

Book ChapterDOI
TL;DR: Several micromechanical models that are currently being used for predicting the thermal and mechanical behavior of a cross-ply, [0/90], titanium matrix composite are evaluated.
Abstract: Several micromechanical models that are currently being used for predicting the thermal and mechanical behavior of a cross-ply, [0/90], titanium matrix composite are evaluated. Six computer programs or methods are compared: (1) VISCOPLY; (2) METCAN; (3) FIDEP, an enhanced concentric cylinder model; (4) LISOL, a modified method of cells approach; (5) an elementary approach where the [90] ply is assumed to have the same properties as the matrix; and (6) a finite element method. Comparisons are made for the thermal residual stresses at room temperature resulting from processing, as well as for stresses and strains in two isothermal and two thennomechanical fatigue test cases. For each case, the laminate response of the models is compared to experimental behavior, while the responses of the constituents are compared among the models. The capability of each model to predict frequency effects, inelastic cyclic strain (hysteresis) behavior, and strain ratchetting with cycling is shown. The basis of formulation for the micromechanical models, the constitutive relationships used for the matrix and fiber, and the modeling technique of the [90] ply are all found to be important factors for determining the accurate behavior of the [0/90] composite.