This article discusses composites for unmanned space vehicles and provides an overview of key design drivers, challenges, and environment for use of composites in spacecraft, launch vehicles, and missiles. It describes the design allowable properties of composite materials. The article provides information on the specific state-of-the-art applications of composite materials for spacecraft missiles and launch vehicles. A discussion on key applications, including solid rocket motor casings, payload fairings, and payload support structures, is presented.

Filament winding is a process for fabricating a composite structure in which continuous reinforcements, either previously impregnated with a matrix material or impregnated during winding, are placed over a rotating form or mandrel in a prescribed way to meet certain stress conditions. This article describes the advancements in filament-winding and lists the advantages and disadvantages of filament winding. The article discusses the effects of fiber tension in filament winding and the selection of fibers, resins, and materials for filament winding. It discusses the three basic filament-winding patterns, such as helical, polar, and hoop. The article presents information on the applications of filament winding, including rocket motors, natural gas vehicle (NGV) tanks, and sporting goods. It recommends basic design guidelines for filament-winding design/manufacturing process and concludes with a discussion on fabrication recommendations.

The selection of materials for welded construction applications involves a number of considerations, including design codes and specifications. Mobile structures have quite different materials requirements for weight, durability, and safety than stationary structures, which are built to last for many years. This article provides an overview of the service conditions. It offers guidance for material selection applications, including bridges and buildings, pressure vessels and piping, shipbuilding and offshore structures, aerospace systems, machinery and equipment, automobiles, railroad systems, and sheet metal. Material properties and welding processes that may be significant in meeting design goals are also described.

Metal powders are used as fuels in solid propellants, fillers in various materials, such as polymers or other binder systems, and for material substitution. They are also used in food enrichment, environmental remediation market, and magnetic, electrical, and medical application areas. This article reviews some of the diverse and emerging applications of ferrous and nonferrous powders. It also discusses the functions of copier powders and the processes used frequently for copier powder coating.

Conventional high-strength aluminum alloys produced via powder metallurgy (P/M) technologies, namely, rapid solidification (RS) and mechanical alloying (mechanical attrition) have high strength at room temperature and elevated temperature. This article focuses on the metallurgy and weldability of dispersion-strengthened aluminum alloys based on the aluminum-iron system that are produced using various RS-P/M processing techniques. It describes weldability issues related to weld solidification behavior, the formation of hydrogen-induced porosity in the weld zone, and the high-temperature deformation behavior of these alloys, which affect the selection and application of fusion and solid-state welding processes. The article provides specific examples of material responses to welding conditions and highlights the microstructural development in the weld zone.

This article provides a brief introduction to lubrication as a method to reduce friction between two surfaces. It discusses the surface characteristics of parts and explores how lubrication helps separate two contacting surfaces and thereby decreases the coefficient of friction. The article details the classifications of lubrication regimes, namely, boundary, mixed, hydrodynamic, and elastohydrodynamic lubrications. It discusses the various types of lubricant materials and additives, including liquid lubricants, solid lubricants, gaseous lubricants, greases, green lubricants, and nanomaterials. The article also reviews the properties of lubricants. It describes the tribological evaluation of lubricants, including stribeck test, four-ball test, block-on-ring test, pin-in-vee test, and reciprocating motion test.

This article commences with a schematic illustration of a wide range of cutter configurations available for use in milling operations. It describes the various types of milling machines classified based on the type of construction, such as knee-and-column type, bed-type, planer-type, and special type. The article discusses mechanical-electric, mechanical-hydraulic, mechanical-electric-hydraulic, and numerical control of milling machines. It describes various types of milling cutters, such as peripheral mills, face mills, end mills, and special mills. Milling cutters, such as solid milling cutters, inserted-blade cutters, and indexable-insert cutters, are also discussed. The article explains the capabilities and limitations of peripheral milling, face milling, and end milling methods. It concludes with a comparison of milling with broaching, planing or shaping, and grinding.

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.

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.

This article describes the roll forming of components of nickel, titanium, and aluminum alloys. The metallurgical characteristics of the roll formed components, such as macrostructures, microstructures, tensile strength, and stress rupture performance, are discussed. The article compares the resulting properties of roll formed and conventionally forged components.

Computed tomography (CT) is an imaging technique that generates a three-dimensional (3-D) volumetric image of a test piece. This article illustrates the basic principles of CT and provides information on the types, applications, and capabilities of CT systems. A comparison of performance characteristics for film radiography, real-time radiography, and X-ray computed tomography is presented in a table. A functional block diagram of a typical computed tomography system is provided. The article discusses CT scanning geometry that is used to acquire the necessary transmission data. It also provides information on digital radiography, image processing and analysis, dual-energy imaging, and partial angle imaging, of a CT system.

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 discusses the wrought product forms of titanium and titanium-base alloys, which include forgings and the typical mill products with tabulations for various specifications, and compares specifications for pure titanium, titanium alloys for mechanical, physical properties and chemical properties, including chemical composition, corrosion resistance, and chemical reactivity. The Article discusses the effects of alloying elements in titanium alloys, and describes the classes of titanium alloys, namely, alpha alloys, alpha-beta alloys, and beta alloys. It also describes the typical applications of various titanium-base materials, and explains the crystal structure, effect of impurities, and microstructural constituents of titanium alloys. The Article provides a brief description on the processing of wrought titanium alloys, including primary fabrication in which ingots are converted into general mill products and secondary fabrication (forging, extrusion, forming, machining, chemical milling and joining) of finished shapes from mill products and the heat treatment of titanium alloys.

Metal-matrix composites (MMCs) are a class of materials with a wide variety of structural, wear, and thermal management applications. This article discusses primary processing methods that are used to manufacture discontinuous aluminum MMCs, namely, high-pressure die casting, pressure infiltration casting, liquid metal infiltration, spray deposition, and powder metallurgy methods. It describes the processing of continuous fiber-reinforced aluminum, discontinuously, reinforced titanium, and continuous fiber-reinforced titanium. The article concludes with information on work done to develop magnesium, copper, and superalloy MMCs.

Braided structures are unique in their high level of conformability, torsional stability, and damage resistance. This article describes the classifications of braiding such as two-dimensional braiding and three-dimensional braiding. It presents governing equations for computer-controlled braiding in a table. A tabulation of applications of braided fabrics and composites is also provided. The article discusses the formation, structure, and properties, such as damage tolerance and impact damage limitation, of two-dimensional braid composites and three-dimensional braid composites.

This article describes the types of fabrics and preforms that are used in the manufacture of advanced composites and related selection, design, manufacturing, and performance considerations. The types of fabrics and performs include unidirectional and two-directional fabrics; multidirectionally reinforced fabrics; hybrid fabrics; woven fabric prepregs; unidirectional and multidirectional tape prepregs; and prepreg tow. The article discusses the three major categories of tape manufacturing processes, namely, hand lay-up, machine-cut patterns that are laid up by hand, and automatic machine lay-up. It provides a description of the two classes of prepregs. These include those suitable for high-performance applications and those suitable for lower-performance molding compounds.

Nickel in elemental form or alloyed with other metals and materials has made significant contributions to our present-day society and promises to continue to supply materials for a demanding future. This Article provides a historical overview and physical metallurgy of nickel and nickel alloys. It lists and describes the compositions, mechanical and physical properties, and applications of commercial nickel and its alloys. The Article briefly explains the forms of corrosion resulting from the exposure of nickel alloys to aqueous environments. It provides valuable information on the commercial forms of nickel alloys, namely, nickel-copper alloys, nickel-chromium and nickel-chromium-iron series, iron-nickel-chromium alloys, controlled-expansion alloys, nickel-iron low-expansion alloys, soft magnetic alloys, and welding alloys.

This article provides assistance to a failure analyst in broadening the initial scope of the investigation of a physical engineering failure in order to identify the root cause of a problem. The engineering design process, including task clarification, conceptual design, embodiment design, and detail design, is reviewed. The article discusses the design process at the personal and project levels but takes into consideration the effects of some higher level influences and interfaces often found to contribute to engineering failures.

Cermet is an acronym that is used to designate a heterogeneous combination of metal(s) or alloy(s) with one or more ceramic phases to incorporate the desirable qualities and suppress the undesirable properties of both materials. The resulting superior new materials are available for a multitude of high-temperature applications, a significant among thoseinvolves cutting tool materials. This Article discusses the classifications of cermets according to their hard refractory component, chemical bonding, chemical composition, microstructure, physical and mechanical properties, and applications of different types of cermets, including oxide cermets, carbide and carbonitride cermets, boride cermets, and other refractory cermets. It provides a brief description of the major fabrication techniques, powder preparation, forming, and post treatments of cermets, which include static cold and hot pressing, cold hydrostatic pressing, powder-injection molding, warm and hot extrusion, powder rolling, slip casting, hot isostatic pressing, infiltration, sintering, and combination sintering-compacting.

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