This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of a type of resin-matrix composites, carbon-epoxy composites. The fractographs illustrate the fracture modes found in composite prepregs, composite panels, solid rocket motor nozzles, and tension, flexural, compressive, and shear loadings.

This article describes the resin and fabrication requirements associated with fiberglass-reinforced plastic equipment. It provides a discussion on various resins and their resistance to various environments. These include polyester, epoxy, epoxy vinyl-ester, and furan and phenolic thermosetting resins. The article concludes with a discussion on the curing system of the thermosetting resins with a wide variety of hardener types.

This article discusses the composition of major components of dental composite resins. The components include organic resin matrix, filler, coupling agents, and initiator-accelerator systems. The article provides a description of three steps in adhesive systems, namely, etching, priming, and the placement of a resin adhesive layer. It describes the properties of composite resins that are related to the amount and type of filler and resin-matrix compositions. The article also provides a discussion on the compositions, properties, and clinical applications of polyacid-modified composite resins and resin-modified glass-ionomer cements. It discusses the biodegradation and biocompatibility of resin-based restorative materials.

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 introduces the principal methodologies and some advanced technologies that are being applied for nondestructive evaluation (NDE) of fiber-reinforced polymer-matrix composites. These include acoustic emission, ultrasonic, eddy-current, computed tomography, electromagnetic acoustic transducer, radiography, thermography, and low-frequency vibration methods. The article also provides information on NDE methods commonly used for metal-matrix composites.

This article describes the use of conventional machining techniques, laser cutting and water-jet cutting for producing finished composite parts. It explains two representative polymer-matrix composites--graphite and aramid composites--and discusses the machining and drilling problems such as delamination and fiber or resin pullout. The article describes machining and drilling techniques and the necessary tools and cutting parameters. It presents a description of laser cutting. The article also provides information on the advantages, disadvantages, cutting characteristics, and applications of water-jet cutting and abrasive water-jet cutting.

This article provides an overview of environmental performance of the most commonly used nonmetallic materials. The materials include elastomers, plastics, thermosetting resins, resin-matrix composites, organic coatings, concrete, refractories, and ceramics. The article also provides information on the applications and uses of these materials.

The structural efficiency of a composite structure is established by its joints and assembly. Adhesive bonding, mechanical fastening, and fusion bonding are three types of joining methods for polymer-matrix composites. This article provides information on surface treatment and the applications of adhesive bonding. It discusses the types of adhesives, namely, epoxy adhesives, epoxy-phenolic adhesives, condensation-reaction PI adhesives, addition-reaction PI adhesives, bismaleimide adhesives, and structural adhesives. The article provides information on fastener selection considerations, including corrosion compatibility, fastener materials and strength, head configurations, importance of clamp-up, interference fit fasteners, lightning strike protection, blind fastening, and sensitivity to hole quality. Types of fusion bonding are presented, namely, thermal welding, friction welding, electromagnetic welding, and polymer-coated material welding.

Ultrasonic inspection is a nondestructive technique that is useful in both quality control and research applications for flaw detection in fiber-reinforced composite materials. This article describes ultrasonic nondestructive analysis by outlining its three basic types of scans. It reviews the important quality control techniques used during the manufacture of composite components by analyzing tooling control, material control, pattern orientation control, and in-process control.

Ceramic-matrix composites (CMCs) are being developed for a number of high-temperature and high-performance applications in industrial, aerospace, and energy conservation sectors. This article focuses on processing, fabrication, testing, and characterization methods of CMCs, namely, discontinuously reinforced composites and continuous-fiber-reinforced composites. Processing methods include cold pressing, sintering, hot pressing, reaction bonding, melt infiltration, directed metal oxidation, sol-gel and polymer pyrolysis, self-propagating high-temperature synthesis and joining. A table summarizes the properties of various ceramic reinforcements and industrial applications of these composites.

The design and analysis of aerospace and industrial composite components and assemblies requires a detailed knowledge of materials properties, which, in turn, depend on the manufacturing, machining, and assembly methods used. This article, through several tables and graphs, provides the mechanical properties, physical properties, and service characteristics of representative composite fiber-resin combinations, including thermoplastic matrix composites such as thermoplastic polyester resins, thermoplastic polyamide resins, and thermoplastic polysulfone resins, and thermoset matrix composites such as thermoset polyester resins, thermoset phenolic resins, thermoset epoxy resins, thermoset polyimide resins, and thermoset bismaleimide resins.

Tensile testing of fiber-reinforced composite materials is performed to determine uniaxial tensile strength, Young’s modulus, and Poisson’s ratio relative to principal material directions, and helps in the prediction of the properties of laminates. Beginning with an overview of the fundamentals of tensile testing of fiber-reinforced composites, this article describes environmental exposures that can occur during specimen preparation and testing. These include exposures during specimen preparation, and planned exposure such as moisture, damage (impact), and thermal cycling. The article also discusses the test methods of the four major types of mechanical testing of polymer-matrix composites: tensile, compression, flexural, and shear.

Carbon-carbon composites (CCCs) are introduced in fields that require their high specific strength and stiffness, in combination with their thermoshock resistance, chemical resistance, and fracture toughness, especially at high temperatures. The use of CCCs has expanded as the price of carbon fibers has dropped and their mechanical properties have increased. This article begins with an overview of the carbon conversion processes, fiber properties and microstructures, and interfacial bonding and environmental interaction of carbon fibers, followed by a detailed discussion on the various techniques available for processing CCCs for specific applications, including preform fabrication (fiber weaving), densification, application of protective coatings, and joining. The article closes with a description of the mechanical and physical properties and applications of CCCs. The main applications of CCCs, in terms of money and mass, are in the military, space, and aircraft industries.

Coating technology for carbon-carbon has been driven primarily by the aerospace and defense industries, in applications where the composite is exposed to high-temperature oxidizing environments. The most notable application of coated carbon-carbon is for the nose cap and wing leading edges of the Shuttle Orbiter vehicle. This article details the fundamentals of protecting carbon-carbon composites. It explains various coating deposition techniques: pack cementation, chemical vapor deposition, and slurry coatings. The article discusses typical coating architectures in accordance with the process used to deposit the primary oxygen barrier. It also provides information on the practical limitations of coatings for the composites.

Sheet molding compound (SMC) is a composite material - consisting of glass-fiber-reinforced polyester in a resin matrix - that’s available in sheet form for the production of compression-molded parts. This article discusses the components incorporated into the resin paste, including catalysts, fillers, thickeners, pigments, thermoplastic polymers, flame retardants, and ultraviolet absorbers, and how to optimize them to achieve the desired processing and molding characteristics and the necessary properties in the resulting parts. The article also presents several mixing techniques, including batch, batch/continuous, and continuous mixing, and describes the operations of continuous-belt and beltless machine type SMCs.

A thermosetting resin, or thermoset, is a synthetic organic polymer that cures to a solid, infusible mass by forming a three-dimensional network of covalent chemical bonds. Significant applications include construction and thermoset engineering plastics. This article discusses the general and family characteristics of thermosetting resin families, including allyls, aminos (urea formaldehyde and melamine formaldehyde), cyanates, epoxies, polybenzimidazoles, unsaturated polyesters, thermoset polyimides, phenolics, and vinyl esters. It also explains processing methods, including curing and curing agents. The article provides descriptions of commercial product forms and the wide array of applications of thermosetting resins. It also tabulates the performance properties (mechanical, thermal, electrical and chemical resistance) of some families of unfilled or unreinforced thermosetting resins and reinforced or filled grades.

This article addresses the types, properties, forms, and applications of fibers that are available for use in fiber-reinforced polymeric matrix composites, including glass, graphite, carbon, aramid, boron, silicon carbide, ceramic, continuous oxide and discontinuous oxide fibers. It describes the functions, types, and chemical composition of fiber sizing agents. The article discusses the styles, properties, applications, and weaving methods of unidirectional, two-directional and multidirectionally reinforced fabrics. The article also reviews the use of prepreg resins in aerospace and lower performance applications.

Shell molding is used for making production quantities of castings that range in weight from a few ounces to approximately 180 kg (400 lb), in both ferrous and nonferrous metals. This article lists the limitations or disadvantages of shell mold casting. It describes the two methods for preparation of resin-sand mixture for shell molding, namely, mixing resin and sand according to conventional dry mixing techniques, and coating the sand with resin. Shaping of shell molds and cores from resin sand mixtures is accomplished in machines. The article discusses the major steps in producing a mold or core and describes the problems most frequently encountered in shell-mold casting. The problems include mold cracking, soft molds, low hot tensile strength of molds, peelback, and mold shift. The article concludes with information on examples that provide some relative cost comparisons between shell molding and green sand molding.

This article provides a detailed discussion on the principal classes and curatives of epoxy resins used in the coatings industry. The principal classes are bisphenol A epoxy, bisphenol F epoxy, epoxy phenol novolac, cycloaliphatic epoxies, epoxy acrylate, brominated bisphenol-A-based epoxy, phosphorus-containing epoxy, fluorinated epoxies, epoxy esters, epoxy phosphate esters, and waterborne epoxy. The principal curatives are amines, amine adducts, cyanoethylated amines, ketimines, polyoxyalkylene amines, cycloaliphatic amines, aromatic amines, polyamides, amido amines, and dicyandiamides. Other curatives include polyester co-polymers, phenolic co-polymers, melamine and urea formaldehyde co-polymer resins, phosphate flame retardants, ultraviolet and electron beam curing of epoxy resins, Mannich bases, Mannich-based adducts, and anhydrides. The article concludes by discussing the concerns regarding the use of epoxy coatings.