Search Results for metallic matrices

Metallic matrices are essential constituents for the fabrication of metal-matrix composites (MMCs). This article describes three different classes of aluminum alloys, namely, commercial aluminum alloys, low-density and high-modulus alloys, and high temperature alloys. It presents typical tensile properties and fracture toughness of the selected heat treatable aluminum alloys in a table. Titanium alloys are very attractive for MMC applications, due to their higher strength and temperature capability compared to aluminum alloys. The article tabulates the effect of heat treatment on room-temperature properties and tensile properties of Ti-25Al-17Nb alloy sheet.

Spinodal transformation is a phase-separation reaction that occurs from kinetic behavior. This article discusses the theory of spinodal decomposition, and outlines the methods used in the characterization of spinodal structures in metal matrices.

This article highlights the selected applications of advanced polymer-matrix composites, metal-matrix composites, and ceramic matrix composites.

This article discusses the types, properties, and uses of continuous-fiber-reinforced composites, including glass, carbon, aramid, boron, continuous silicon carbide, and aluminum oxide fiber composites. While polyester and vinyl ester resins are the most used matrix materials for commercial applications, epoxy resins, bismaleimide resins, polyimide resins, and thermoplastic resins are used for aerospace applications. The article addresses design considerations as well as product forms and fabrication processes.

This article focuses on the process methods and matrix chemistries of ceramic-matrix composites. These methods include pressure-assisted densification, chemical vapor infiltration, melt infiltration, polymer infiltration and pyrolysis, and sol-gel processing. The article discusses the use of a ceramic, preceramic, or metal phase as a fluid or vapor phase reactant to form the matrix. Emphasis is placed on microstructural features that influence ultimate composite properties.

This article provides a summary of the concepts discussed in the articles under the Section “Constituent Materials” in ASM Handbook, Volume 21: Composites. The Section describes the major matrix resins and reinforcing fibers used in composite materials, as well as some of the intermediate material forms available for composite fabrication.

This article begins with a brief history of composite materials and discusses its characteristics. It presents an introduction to the constituents, product forms, and fabrication processes of composite materials. The article concludes with a discussion on the applications of organic-matrix, metal-matrix, and ceramic-matrix composites.

This article begins with a discussion on fiber-reinforced composite materials and describes the generic behavior and structure/property relationships of composites. The article summarizes lamina properties and presents equations that help in the calculation of lamina properties. Composite laminates are constructed from lamina with uniaxial fiber orientation and frequently from textile fabrics as well. The article explains the characteristics of symmetric in-plane and through-thickness laminates; asymmetric in-plane and symmetric through-thickness laminates; asymmetric laminates; and curved laminates. It provides information on controlled thermal expansion composites, metal-matrix composites, and ceramic-matrix composites. The article illustrates the types of bonded joints and concludes with a discussion on design for manufacturing.

Friction materials are the components of a mechanism that converts mechanical energy into heat upon sliding contact. This article discusses the selection criteria, manufacturing process, and applications of friction powder metallurgy materials. It provides information on the manufacturing process of powder metallurgy friction materials through a process of mixing/blending, compacting, and sintering. The final machining that they undergo, to ensure that they meet dimensional specifications, is also discussed.

Metal matrix composites (MMCs) can be synthesized by vapor phase, liquid phase, or solid phase processes. This article emphasizes the liquid phase processing where solid reinforcements are incorporated in the molten metal or alloy melt that is allowed to solidify to form a composite. It illustrates the three broad categories of MMCs depending on the aspect ratio of the reinforcing phase. The categories include continuous fiber-reinforced composites, discontinuous or short fiber-reinforced composites, and particle-reinforced composites. The article discusses the two main classes of solidification processing of composites, namely, stir casting and melt infiltration. It describes the effects of reinforcement present in the liquid alloy on solidification. The article examines the automotive, space, and electronic packaging applications of MMCs. It concludes with information on the development of select cast MMCs.

This article explains the key features of the manufacturing techniques for polymer composites. It describes the selection of a technically and economically feasible manufacturing technique for a composite design. The article discusses widely accepted and emerging techniques to manufacture polymer composites such as open-mold techniques.

This article illustrates the polymer matrices used for composite materials. It describes the use of prepeg materials in manufacturing high-performance composites. The article discusses the various infusion processes for the development of fiber-reinforced composites, namely, resin transfer molding, vacuum-assisted resin transfer molding, and resin film infusion. It explains the composite- and matrix-toughening methods for fiber-reinforced composites, such as dispersed-phase toughening and interlayer toughening. The article concludes with information on optical microscopy, which provides an insight into the micro- and macrostructure of fiber-reinforced composites.

Microstructural analysis of the composite matrix is necessary to understand the performance of the part and its long-term durability. This article focuses on the microstructural analysis of engineering thermoplastic-matrix composites and the influence of cooling rate and nucleation on the formation of spherulites in high-temperature thermoplastic-matrix carbon-fiber-reinforced composites. It also describes the microstructural analysis of a bio-based thermosetting-matrix natural fiber composite system.

This article begins with a discussion on the criteria for evaluating computer programs for composites structural analysis, including database capabilities, types of engineering calculations supported, interface and operating systems, and technical support. It describes the capabilities of programs, such as CompositePro, ESAComp, and V-Lab that provide a graphical interface, built-in databases, and integrated modules for the different types of analyses. The article reviews the modules of other programs used for composite analysis. The programs include ASCA, CADEC, CoDA, COMPASS, ESDU, LAP, PROMAL, and SACL. The article concludes with information on on-line programs and recourses.

This article illustrates typical fractographic features for a number of different composite materials. It describes the differences in fracture characteristics due to different loading, material processing, and environmental conditions. The article presents fractographic data obtained from epoxy matrix materials. Minimal fractographic data from other brittle thermoset resin systems are also presented. The article discusses the interlaminar fracture of composites with ductile thermoplastic matrices. It also provides information on the translaminar fracture features of the composite materials.

This article discusses the solidification of a matrix alloy in cast metal matrix composites (MMCs). It begins with a discussion on the mixing techniques in reinforcement incorporation and wettability of reinforcement. It describes the solidification processes, such as stir mixing and melt infiltration, used in the synthesis of MMCs. The article also considers the fundamentals of the process and presents a computational modeling of particle/solidification front interactions in metal-ceramic systems. The article concludes with information on nanocomposites.

Superconductors are materials that exhibit a complete disappearance of electrical resistivity on lowering the temperature below the critical temperature. A superconducting material must exhibit perfect diamagnetism, that is, the complete exclusion of an applied magnetic field from the bulk of the superconductor. Superconducting materials that have received the most attention are niobium-titanium superconductors (the most widely used superconductor), A15 compounds (in which class the important ordered intermetallic Nb3Sn lies), ternary molybdenum chalcogenides (Chevrel phases), and high-temperature ceramic superconductors. This article provides an overview of basic principles of superconductors and the different classes of superconducting materials and their general characteristics.

This article describes the various pure forms of carbon matrices and the corresponding methods used to create them or incorporate them into a matrix of a composite. These forms include graphite, diamond, fullerenes, and nanotubes. The article discusses the three types of liquid precursors, namely, thermoplastic, thermosetting, and evaporative or solvent carriers. It provides a description of the advantages and limitations of various methods involved in chemical vapor infiltration. The article concludes with a discussion on matrix contribution to composite properties.

This article discusses the mechanisms for enhancing the reliability of three types of ceramic-matrix composites: discontinuously reinforced ceramic-matrix composites, continuous fiber ceramic composites, and carbon-carbon composites. It also presents examples of their mechanical and physical properties. Examples that illustrate the properties of commercially available materials are also provided.

A test plan specifies material properties to be evaluated, selects test methods, eliminates options offered by standard test methods by selecting specific specimen and test configurations, and defines success criteria. This article discusses various testing objectives that affect the execution of testing programs. The testing objectives include development of test matrices, testing standards, specimen preparation, environmental conditioning, instrumentation and data acquisition, failure modes, and data interpretation and recording.