Search Results for foil interlayers

This article describes low-temperature solid-state welding processes in relation to the interlayer fabrication method, welding method, and welding parameters. The interlayer fabrication method is used to produce vacuum coated interlayers, electrodeposited interlayers, and foil interlayers. The article discusses welding methods, including uniaxial compression and hot isostatic pressing. The article provides information on the effect of base-metal surface finish on the tensile strength of joints solid-state welded using silver interlayers in tabular form and addresses the surface cleaning steps of base-metals.

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.

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.

Diffusion welding involves minimal pressurization, but relatively high temperatures and long periods of time. This article discusses the process variants of diffusion welding: solid-phase and liquid-phase processes. It describes the diffusion welding of carbon and low-alloy steels, high-strength steels, stainless steels, and aluminum-base alloys. The article provides a discussion on dissimilar metal combinations, such as ferrous-to-ferrous combinations, nonferrous-to-nonferrous combinations, ferrous-to-nonferrous combinations, and metal-ceramic joining.

This article describes the solid-phase and liquid-phase processes involved in diffusion bonding of metals. It provides a detailed discussion on the diffusion bonding of steels and their alloys, nonferrous alloys, and dissimilar metals. Ceramic-ceramic diffusion welding and a variation on this process in which ceramic powder compacts are simultaneously sintered and bonded are also discussed.

This article begins with a discussion on the advantages and limitation of ultrasonic welding (USW). It describes variations of the USW process which can produce different weld geometries. These variations are helpful in producing spot welds, line welds, continuous seam welds, ring welds, and microelectronic welds. The article provides information on the functions of USW personnel and describes the special conditions in USW which include the condition of the surface, the use of an interlayer, and the control of resonance. It concludes with a description on the weld quality, the influencing factors, surface appearance and deformation, and metallographic examination.

Ultrasonic additive manufacturing (UAM) is a solid-state hybrid manufacturing technique that leverages the principles of ultrasonic welding, mechanized tape layering, and computer numerical control (CNC) machining operations to create three-dimensional metal parts. This article begins with a discussion on the process fundamentals and process parameters of UAM. It then describes metallurgical aspects in UAM. The article provides a detailed description of a wide range of mechanical characterization techniques of UAM, namely tensile testing, peel testing, and pushpin testing. The article ends with information on sensor embedding.

Lightning damage in polymer composites is manifested by damage at both the macroscopic or visual level and within the material microstructure. This article illustrates the effects of the laboratory-generated lightning strikes on polymeric composites.

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.

This article discusses the effects of brazing temperature and thermal treatment on structure and mechanical behavior of different classes of titanium base metals such as commercially pure (CP) titanium, alpha or near-alpha alloys, alpha-beta alloys, and beta alloys. The classification, properties, and potential heat treatment of titanium base alloys are presented in tables. The article provides information on brazed joints of titanium with carbon steels, as well as ceramics and graphite. It discusses the risks involved in titanium brazing, including erosion of base metal, brittle intermetallics, and low ductility. The article reviews induction and torch brazing, infrared brazing, diffusion brazing, and brazing by heating with ion bombardment. It concludes by describing the design criteria and limitations of brazing.

This article describes two variations of carbon-base coatings: diamondlike carbon (DLC) coatings and polycrystalline diamond (PCD) coatings. It discusses the basics of a few deposition methods as they apply to industrially relevant coatings. The methods include deposition of tungsten-containing hydrogenated amorphous carbon films, deposition of tetrahedral amorphous carbon films, and deposition of silicon-incorporated hydrogenated amorphous carbon films. The most common deposition technologies for diamond films are also discussed. The article provides information on surface preparation for DLC and diamond deposition. It also provides a discussion on the coating composition and structure, mechanical and tribological properties, and applications of DLC and diamond coatings. The quality control techniques for DLC and diamond coatings are specified to meet customer requirements and ensure repeatable quality.

This article is intended to assist the development of procedures for the brazing of ceramic-to-ceramic or ceramic-to-metal joints for service under elevated temperatures, mechanical or thermal stresses, or corrosive atmospheres. It describes the factors considered in preparing a procedure for the brazing of graphitic materials.

This article reviews quantifying adhesion, bonding, and interfacial characterization and strength in a solid-state welding process. It discusses metal-metal configurations and provides information on experimental work carried out in measuring the mechanical properties of interfaces based on theoretical analysis. A discussion on the properties affecting adhesion is also provided.

Design and analysis of electrical/electronic systems and components tends to be different from the corresponding process for most mechanical and hydraulic systems. This article provides an overview of three overlapping phases followed in electrical design: functional, electrical, and physical. It also presents information on the simulation and testing carried out to evaluate the design behavior.

This article describes the factors considered in the analysis of brazeability and solderability of engineering materials. These are the wetting and spreading behavior, joint mechanical properties, corrosion resistance, metallurgical considerations, and residual stress levels. It discusses the application of brazed and soldered joints in sophisticated mechanical assemblies, such as aerospace equipment, chemical reactors, electronic packaging, nuclear applications, and heat exchangers. The article also provides a detailed discussion on the joining process characteristics of different types of engineering materials considered in the selection of a brazing process. The engineering materials include low-carbon steels, low-alloy steels, and tool steels; cast irons; aluminum alloys; copper and copper alloys; nickel-base alloys; heat-resistant alloys; titanium and titanium alloys; refractory metals; cobalt-base alloys; and ceramic materials.

This article describes the structure of coatings produced by plasma spraying, vapor deposition, and electrodeposition processes. The main techniques used for microstructure assessment are introduced. The relationship between the microstructure and property is also discussed. The experimental techniques for microstructural characterization include metallographic technique, X-ray diffraction, electron, microscopies, and porosimetry.

Weldability is a function of three major factors: base material quality, welding process, and design. This article focuses on base-metal weldability of aluminum alloys in terms of mechanical property degradation in both the weld region and heat-affected zone, weld porosity, and susceptibility to solidification cracking and liquation cracking. It provides an overview on welding processes, including gas metal arc welding, gas tungsten arc welding, resistance spot and seam welding, laser beam welding, and various solid-state welding processes. A review on joint design is also included, mainly in the general factors associated with service weldability (fitness). The article also provides a discussion on the selection and weldability of non-heat-treatable aluminum alloys, heat treatable aluminum alloys, aluminum-lithium alloys, and aluminum metal-matrix composites.

Metal-matrix composites (MMCs) are used in structural applications, and in applications requiring wear resistance, thermal management, and weight savings. This article summarizes the mechanical and thermal properties of discontinuously reinforced aluminum MMCs, laminated metallic composites, and continuously aligned fiber reinforced MMCs.

Brazing technology is continually advancing for a variety of metals including aluminum and its alloys and nonmetals. This article discusses the key physical phenomena in aluminum brazing and the materials for aluminum brazing, including base metals, filler metals, brazing sheet, and brazing flux. It describes various aluminum brazing methods, such as furnace, vacuum, dip, and torch brazing. Friction, flow, induction, resistance, and diffusion brazing are some alternate brazing methods discussed. The article reviews the brazing of aluminum to ferrous alloys, aluminum to copper, and aluminum to other nonferrous metals. It also discusses post-braze processes in terms of post-braze heat treatment and finishing. The article concludes with information on the safety precautions considered in brazing aluminum alloys.

Soldering represents the primary method of attaching electronic components, such as resistors, capacitors, or packaged integrated circuits, to either printed wiring board whose defects is minimized by consideration of proper PWB design, device packages, and board assembly. This article discusses the categories that are most important to successful electronic soldering, namely, solders and fluxes selection, nature of base materials and finishes, solder joint design, and solderability testing.