This article focuses on the forging characteristics of different types of refractory metals and alloys, namely, niobium and niobium alloys, molybdenum and molybdenum alloys, tantalum and tantalum alloys, and tungsten and tungsten alloys.

This article briefly discusses the annealing practices for refractory metals such as tungsten, molybdenum, niobium, tantalum, and rhenium and their alloys. It also presents the applications and properties of these metals and their alloys.

The refractory metals include niobium, tantalum, molybdenum, tungsten, and rhenium. They are readily degraded by oxidizing environments at moderately low temperatures. Protective coating systems have been developed, mostly for niobium alloys, to permit their use in high-temperature oxidizing aerospace applications. This article discusses the properties, processing, applications, and classes of refractory metals and its alloys, namely molybdenum, tungsten, niobium, tantalum and rhenium. It also provides an outline of the coating processes used to improve their oxidation resistance.

This article addresses surface cleaning, finishing, and coating operations that have proven to be effective for molybdenum, tungsten, tantalum, and niobium. It describes standard procedures for abrasive blasting, molten caustic processing, acid cleaning, pickling, and solvent and electrolytic cleaning as well as mechanical grinding and finishing. The article also provides information on common plating and coating methods, including electroplating, anodizing, and oxidation-resistant coatings.

This article discusses surface engineering of nonferrous metals including aluminum and aluminum alloys, copper and copper alloys, magnesium alloys, nickel and nickel alloys, titanium and titanium alloys, zirconium and hafnium, zinc alloys, and refractory metals and alloys. It describes various techniques to improve functional surface properties and enhance the appearance of product forms. The article discusses various cleaning and finishing techniques such as abrasive blast cleaning, polishing and buffing, barrel burnishing, chemical cleaning, pickling, etching and bright dipping, electrochemical cleaning, mechanical cleaning, and mass finishing. It also examines coating processes such as plating, anodizing, chemical conversion coating, and thermal spray, and concludes with a discussion on oxidation-resistant coatings for refractory metals.

Characteristics of stainless steel that affect its formability include yield strength, tensile strength, and ductility, in addition to the effect of work hardening on these properties. This article discusses the forming process of stainless steel, heat-resistant alloys and refractory metals, detailing the major aspects of forming, including formability, lubrication, and forming methods and tools. The effect of factors such as alloy condition, cold reduction, forming direction (in the case of heat-resistant alloys) and temperature (in the case of refractory metals) on formability is also discussed.

This article describes the metallographic technique for nonferrous metals and special-purpose alloys. These include aluminum alloys, copper and copper alloys, lead and lead alloys, magnesium alloys, nickel and nickel alloys, magnetic alloys, tin and tin alloys, titanium and titanium alloys, refractory metals and alloys, zinc and zinc alloys, and wrought heat-resisting alloys. The preparation of specimens for metallographic technique includes operations such as sectioning, mounting, grinding, polishing, and etching of nonferrous metals and alloys. The article contains tables that list the etchants for macroscopic examination and microscopic examination of nonferrous metals and special-purpose alloys.

Heat treating of stainless steel produces changes in physical condition, mechanical properties, and residual stress level and restores maximum corrosion resistance when that property has been adversely affected by previous fabrication or heating. This article focuses on annealing of different types of stainless steels such as austenitic, ferritic, duplex, martensitic, and precipitation-hardening, and on the heat treatment of superalloys and refractory metals. It discusses the recommended procedures for solution annealing, austenite conditioning, transformation cooling, and age tempering of precipitation-hardening stainless steels. The article also lists general recommendations for the annealing temperatures of tantalum, niobium, molybdenum, tungsten, and their alloys.

This article provides an overview of the corrosion theory relating to refractories on the basis of acid/base reactions, thermodynamics, and kinetic considerations. The tests to evaluate refractory corrosive wear are reviewed. The article describes the specific refractories used in steel, glass, aluminum, and chemical-resistant applications. Specific material issues that should be considered or evaluated when choosing or using refractory materials are discussed.

Metal-matrix composites (MMCs) are a class of materials with potential for a wide variety of structural and thermal applications. This article discusses the mechanical properties of MMCs, namely aluminum-matrix composites, titanium-matrix composites, magnesium-matrix composites, copper-matrix composites, superalloy-matrix composites, and intermetallic-matrix composites. It describes the processing methods of discontinuous aluminum MMCs which include casting processes, liquid-metal infiltration, spray deposition and powder metallurgy. The article provides useful information on aluminum MMC designation system and also describes the types of continuous fiber aluminum MMCs, including aluminum/boron MMC, aluminum/silicon carbide MMC, aluminum/graphite MMC, and aluminum/alumina MMC.

In the handling of molten aluminum, it is fairly common to use filters as a part of the melting unit and in the gating and/or riser system. This article describes the methods of in-furnace and in-mold filtration, with emphasis on the filtration of molten aluminum. It discusses the factors that influence the formation of inclusions. The article describes the three basic methods of mechanically removing or separating inclusions from molten metal. The methods include sedimentation, flotation, and positive filtration. The article provides a discussion on the types of molten-metal filters, including bonded-particle filters, cartridge filters, and ceramic foam filters. It lists the factors that are important in achieving optimum performance of any in-furnace filtering application. The article concludes with information on filtered metal quality.

This article discusses various molten-metal treatments, namely fluxing, degassing, and molten-metal filtration. It focuses on various molten-metal handling systems for transporting, holding, or delivering molten metal to the mold/die system. These include launders, tundishes, holding furnaces or transport crucibles, molten-metal transfer pumps, teeming ladles, and dosing and pouring furnaces.

This article provides an overview of conventional low-pressure casting and describes types of furnaces, tooling, and cores. It discusses the casting cycle steps, advantages, mechanical properties, and considerations of counterpressure casting. The article describes the vacuum riserless/pressure riserless casting process for casting aluminum.

Several qualitative, semiquantitative, and quantitative tests are available to estimate and control metal cleanliness, particularly inclusion concentration of aluminum alloys. This article provides a brief description of few of the metal cleanliness assessment techniques, such as chemical analysis, pressure filter tests, electric resistivity tests, reduced-pressure test, and ultrasonic technique. It also lists the various impurities detection methods of chemical analysis and their limitations.

Casting is one of the most economical and efficient methods for producing metal parts. In terms of scale, it is well suited for everything from low-volume, prototype production runs to filling global orders for millions of parts. Casting also affords great flexibility in terms of design, readily accommodating a wide range of shapes, dimensional requirements, and configuration complexities. This article traces the history of metal casting from its beginnings to the current state, creating a timeline marked by discoveries, advancements, and influential events. It also lists some of the major markets where castings are used.

Homogenization heat treatment can be useful for improving the performance and life of an alloy while in service or for improving the processability during fabrication and hot working. This article describes the identification of incipient melt point, slowest-diffusing elements, and microstructural scale for homogenization of metal alloys. It also discusses the CALPHAD software to optimize the homogenization heat treatment and the Scheil module of the commercial thermodynamic modeling software.

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 development of select cast MMCs.

The melting process often includes refining and treating the metal. The choice of which type of melting to use depends on a number of factors: type of alloy being melted, the local cost of electric power, and local environmental regulations. This article discusses the principles, furnace types, charging practices of metal melting methods, namely induction melting, cupola melting, arc melting, crucible melting, reaction melting, and vacuum melting, and the refractories and charging practice of reverberatory furnaces. Molten metal treatment of steels and aluminum also is discussed in the article.

Cemented carbides belong to a class of hard, wear-resistant, refractory materials in which the hard carbide particles are bound together, or cemented, by a ductile metal binder. Cermet refers to a composite of a ceramic material with a metallic binder. This article discusses the manufacture, composition, classifications, and physical and mechanical properties of cemented carbides. It describes the application of hard coatings to cemented carbides by physical or chemical vapor deposition (PVD or CVD). Tungsten carbide-cobalt alloys, submicron tungsten carbide-cobalt alloys, and alloys containing tungsten carbide, titanium carbide, and cobalt are used for machining applications. The article also provides an overview of cermets used in machining applications.

This article discusses the design parameters, operation, characteristics, properties, and advantages of various types of crucible furnaces, such as stationary, tilting, and movable furnaces. It also provides information on the application of the crucible furnaces.