The initial cast superalloy developments in the United States centered on cobalt-base materials. Nickel-base and nickel-iron-base superalloys owe their high-temperature strength potential to their gamma prime content. For polycrystalline superalloy components, high-temperature strength is affected by the condition of the grain boundaries and, in particular, the grain-boundary carbide morphology and distribution. Vacuum induction melting offers more control over alloy composition and homogeneity than all other vacuum melting processes. The primary purification reaction occurring in the process is the removal of melt contained oxygen by means of a reaction with carbon to form carbon monoxide. A number of casting processes can provide near-net shape superalloy cast parts, but essentially all components are produced by investment casting. The solidification of investment cast superalloy components is precisely controlled so that the microstructure, which ultimately determines mechanical properties, remains consistent. Heat treating cast superalloys involves homogenization and solution heat treatments or aging heat treatments.

Synthetic diamond and cubic boron nitride are among a class of superhard materials from the boron-carbon-nitrogen-silicon family of elements. This article focuses on the two materials, the forms in which they are produced, and their respective properties. Synthetic diamond and cubic boron nitride compounds are available in the form of grit and sintered polycrystalline blanks of various size, shape, and composition. The article explains how superabrasive grains made from these materials can be used in lapping, polishing, and grinding applications, and how diamond and boron nitride blanks can be mounted to suitable substrates to form ultrahard cutting edges and tools.

This article describes the machining operations of carbon fiber-reinforced epoxy, or carbon/epoxy thermoset composite materials, such as drilling, reaming, routing, trimming, end milling, slot milling, and facing. It reviews cutting tools for machining, including solid carbide, diamond plated, brazed diamond, diamond coated carbide, and polycrystalline cutting tools. The article also describes cutting tool materials that are used for peripheral milling, face milling, and the trimming of polymer-matrix composites.

Cast nickel-base alloys are used extensively in corrosive-media and high-temperature applications. This article briefly reviews the common types of heat treatments of nickel alloy castings: homogenization, stress relieving, in-process annealing, full annealing, solution annealing, quenching, coating diffusion, and precipitation. It describes the three general strengthening mechanisms, namely, solid-solution hardening, age hardening, and carbide precipitation. The article summarizes the typical heat treatment of the general families of nickel-base castings used in industrial applications. It focuses on the solution treatment and age hardening of cast nickel-base superalloys and the heat treatment of cast solid-solution alloys for corrosion-resisting applications. The article also discusses the typical types of atmospheres used in annealing or solution treating: exothermic, endothermic, dry hydrogen, dry argon, and vacuum.

This article discusses fracture, fatigue, and creep of nickel-base superalloys with additional emphasis on directionally solidified and single-crystal applications. It analyzes the physical metallurgy of these alloys. The effects of grain boundary and grain size on failure are summarized. The article also discusses the effects of microstructure and extrinsic parameters on fatigue crack propagation (FCP). It details the modeling of FCP rates and creep and creep-fatigue crack growth rates.

Microstructure and crystallographic texture are the key material features used in the continuous endeavor to relate the processing of a metal with its final properties. This article emphasizes several aspects of deformation microstructures, namely, microstructural evolution, dislocation boundaries, and macroscopic properties. It discusses three different microstructural types: cell blocks, TL blocks, and equiaxed subgrains. The article also emphasizes the behavior of metals and single-phase alloys processed under plastic deformation (dislocation slip) conditions. It provides information on the microstructural parameters, measurement techniques, and microstructural relationships, which assist in predicting the mechanical properties and recrystallization behavior of materials. The article concludes with an analysis of the general relationship between the microstructural parameters and properties.

Selecting the proper cutting tool material for a specific machining application can provide substantial advantages, including increased productivity, improved quality, and reduced costs. This article begins with a description of the factors affecting the selection of a cutting tool material. This is followed by a schematic representation of their relative application ranges in terms of machining speeds and feed rates. The article provides a detailed account of chemical compositions of various tool materials, including high-speed tool steels, cobalt-base alloys, cemented carbides, cermets, ceramics, cubic boron nitride, and polycrystalline diamond. It compares the toughness, and wear resistance for these cutting tool materials. Finally, the article explains the steps for selecting tool material grades for specific application.

This article provides information on the infiltration mechanism of carbide structures. It reviews the basic techniques used for metal infiltration, including dip infiltration, contact filtration, gravity feed infiltration, and external-pressure infiltration. The article highlights various applications of contact infiltration in oil, gas, and blast-hole drilling such as fixed-cutter drill bits and diamond-impregnated coring bits. It also discusses the applications of infiltrated carbide material in erosion-resistant cladding.

This article discusses factors that influence the effect of alloying, metallurgical treatments, and mechanical treatments on the corrosion resistance of metallic materials, with schematic illustrations.

Diamond and cubic boron nitride (CBN) are the two hardest materials known. They have found numerous applications in industry, both as ultrahard abrasives and as cutting tools. This article reviews the high-pressure synthesis and fabrication techniques of these materials. It discusses their wear resistance, tool geometries, and machining parameters. The article also explains their application as cutting tools in the field of machining.

Recovery, recrystallization, and grain growth are microstructural changes that occur during annealing after cold plastic deformation and/or during hot working of metals. This article reviews the structure of the deformed state and describes the changes in the properties and microstructures of a cold-worked metal during recovery stage. It discusses the recrystallization that occurs by the nucleation and growth of grains. The article also reviews the growth behavior of the grains, explaining that the grain growth can be classified into two types: normal or continuous grain growth and abnormal or discontinuous grain growth. It also examines the key mechanisms that control microstructure evolution during hot working and subsequent heat treatment. These include dynamic recovery, dynamic recrystallization, metadynamic recrystallization, static recovery, static recrystallization, and grain growth.

Superalloys are nickel, iron-nickel, and cobalt-base alloys generally used for high-temperature applications. Superalloys are used in aircraft, industrial, marine gas turbines, nuclear reactors, spacecraft structures, petrochemical production, orthopedic and dental prostheses, and environmental protection applications. This article discusses the material characteristics, phases, structures, and systems of superalloys. It describes the processing of superalloys, including primary and secondary melting, deformation processing (conversion), powder processing, investment casting, and joining methods. The article also describes the properties, microstructure, and thermal exposure of superalloys. It further discusses the effects of environmental factors on superalloys, including oxidation and hot corrosion. Protective coatings are also discussed. The article provides information on the mechanical properties and chemical composition of nickel, iron, and cobalt-base superalloys in both the cast and wrought forms.

This datasheet provides information on key alloy metallurgy, processing effects on physical and mechanical properties, and application characteristics of Al-Si-Cu-Mg hypereutectic casting alloys 390.0, A390.0, and B390.0. Tool lives for the machining of alloys 380 and 390 are illustrated.