This article is a compilation of definitions for terms related to engineering materials.

This article characterizes the physical differences between powder metallurgy (PM) and wrought or cast materials, as they apply to joining. It discusses acceptable joining procedures and techniques, including welding and brazing and solid-state methods. Information on the weldability of various PM materials is presented. The article also describes the effects of porosity on several important properties that affect the welding characteristics.

This article presents an introduction to brazing, including information on its mechanics, advantages, and limitations. It reviews soldering with emphasis on chronology, solder metals, and flux technology. The article also provides useful information on mass, wave, and drag soldering. It presents a table which contains information on the comparison of soldering, brazing, and welding.

Welded connections are a common location for failures for many reasons, as explained in this article. This article looks at such failures from a holistic perspective. It discusses the interaction of manufacturing-related cracking and service failures and primarily deals with failures that occur in service due to stresses caused by externally applied loads. The purpose of this article is to enable a failure analyst to identify the causative factors that lead to welded connection failure and to identify the corrective actions needed to overcome such failures in the future. Additionally, the reader will learn from the mistakes of others and use principles that will avoid the occurrence of similar failures in the future. The topics covered include failure analysis fundamentals, welded connections failure analysis, welded connections and discontinuities, and fatigue. In addition, several case studies that demonstrate how a holistic approach to failure analysis is necessary are presented.

This article explains how to design a joint or conduct a joining process so that components can be produced most efficiently and without defects. The joining processes include mechanical fastening, adhesive bonding, welding, brazing, and soldering. The article discusses the selection and application of good design practices based on the understanding of process-related manufacturing aspects such as accessibility, quality, productivity, and overall manufacturing cost. It provides several examples of selected parts and joining processes to illustrate the advantages of a specific design practice in improving manufacturability.

Soft-interlayer solid-state welds that join stronger base metals have unique mechanical properties that are of fundamental interest and may be of critical importance to designers. This article discusses the mechanical properties of soft-interlayer solid-state welds and the implications of these behaviors to service stress states and environments. It describes the tensile loading of soft-Interlayer welds in terms of the effect of interlayer thickness on stress, interlayer strain, time-dependent failure, effect of base-metal properties, and effect of interlayer fabrication method. The article concludes with a discussion on multiaxial loading.

This article discusses the mechanical properties of soft-interlayer solid-state welds and the implications of these behaviors to service stress states and environments. It illustrates the microstructure of as-deposited coatings and solid-state-welded interlayers. The article reviews factors that affect the tensile loading of strength of soft-interlayer welds: the interlayer thickness, the interlayer strain, and the interlayer fabrication method. It also provides information on stress-corrosion cracking of interlayers and stress behavior of these interlayers during shear and multiaxial loading.

Joining is key to the manufacture of large or complex devices or assemblies; construction of large and complex structures; and repair of parts, assemblies, or structures in service. This article describes the three forces for joining: physical, chemical, and mechanical. It provides an overview of the joining processes, namely, mechanical fastening, integral attachment, adhesive bonding, welding, brazing, and soldering. The article concludes with information on the various aspects of joint design and location that determine the selection of a suitable joining method.

Post-processing includes various processes that might be required to produce finished components from the ceramic-matrix composites (CMC) materials. The processes consist of machining or finishing operations, coating, joining, assembly operations, and nondestructive evaluation of CMCs and its components. This article discusses the specific needs for science and technology in these areas relative to the goal of employing CMCs in a variety of applications.

Polymeric materials that possess similar solubility parameters can be joined using a variety of polymer joining techniques. This article describes commonly available fusion-welding techniques such as joining methods, key joining parameters, and the application areas of each joining method. The techniques are hot-tool, hot-gas, extrusion, focused infrared, laser, friction, vibration, spin, ultrasonic, and electromagnetic welding techniques (resistance, induction, dielectric, and microwave welding). The article concludes with a discussion on welding evaluation methods.

This article briefly reviews the general causes of weldment failures, which may arise from rejection after inspection or failure to pass mechanical testing as well as loss of function in service. It focuses on the general discontinuities observed in welds, and shows how some imperfections may be tolerable and how the other may be root-cause defects in service failures. The article explains the effects of joint design on weldment integrity. It outlines the origins of failure associated with the inherent discontinuity of welds and the imperfections that might be introduced from arc welding processes. The article also describes failure origins in other welding processes, such as electroslag welds, electrogas welds, flash welds, upset butt welds, flash welds, electron and laser beam weld, and high-frequency induction welds.

This article describes the general concepts and practices related to manufacturing and design. It discusses the activities of design and manufacturing by placing it in the context of the business system that they support. The article presents an overview of the manufacturing technology field from a design and material selection perspective. It provides an insight to the complex relationship among design, material selection, and manufacturing. The article offers information on modern design for manufacturing practices that are widely used in the industry.

This article discusses different types of joining processes, including welding, brazing, soldering, mechanical fastening, and adhesive bonding. It examines two broad classes of welding: fusion welding and solid-state welding. The article discusses the process selection considerations for welding, brazing, and soldering. It also describes joint design considerations such as selection of weld joints and welds.

Many applications of ceramics and glasses require them to be joined to each other or to other materials such as metals. This article focuses on ceramic joining technologies, including glass-metal sealing, glass-ceramic/metal joining, ceramic-metal joining, ceramic-ceramic joining, and the more advanced joining of nonoxide ceramics. It also discusses metallizing, brazing, diffusion bonding, and chemical bonding.

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.

Diffusion bonding is only one of many solid-state joining processes wherein joining is accomplished without the need for a liquid interface (brazing) or the creation of a cast product via melting and resolidification. This article offers a qualitative summary of the theory of diffusion bonding. It discusses factors that affect the relative difficulty of diffusion bonding oxide-bearing surfaces. These include surface roughness prior to welding, mechanical properties of the oxide, relative hardness of the metal and its oxide film, and prestraining or work hardening of the material. The article describes the mechanism of diffusion bonding in terms of microasperity deformation, diffusion-controlled mass transport, and interface migration. It concludes with a discussion on diffusion bonding with interface aids.

Relatively limited effort has gone into developing repair processes and materials for composites, in contrast to the significant labor and expense that has gone into the development of these materials for numerous critical applications. As composites gain wider acceptance as aerospace materials, there is a need to understand the requirements of the end users regarding repair of these advanced materials. This article focuses on the repair of graphite-epoxy structures designed in a variety of forms for a wide range of load intensities. Five repair concepts developed for generic laminate repair have been validated in this article through the required environmental and load condition tests. These include bonded-scarf joint flush repair, double-scarf joint flush repair, blind-side banded-scarf repair, blind-side sandwich repair, and bonded external patch repair. A brief note on thermoplastic repair concepts is also provided in this article.

This article provides a qualitative summary of the theory of diffusion bonding, as distinguished from the mechanisms of other solid-state welding processes. Diffusion bonding can be achieved for materials with adherent surface oxides, but the resultant interface strengths of these materials are considerably less than that measured for the parent material. The article describes three stages of diffusion bonding: microasperity deformation, diffusion-controlled mass transport, and interface migration. It concludes with information on diffusion bonding with interface aids.

This article provides an overview of the principle forms of corrosion that can occur on automotive aluminum components and offers general guidelines on how best to avoid these situations. It discusses the most common forms of aluminum corrosion such as stress-induced corrosion, cosmetic corrosion, crevice corrosion, and galvanic corrosion.