Nickel-base alloys can be machined by techniques that are used for iron-base alloys. This article discusses the effects of distortion and microstructure on the machinability of nickel alloys. It tabulates the classification of nickel alloys based on machining characteristics. The article describes the machining operations performed on nickel alloys, such as turning, planing and shaping, broaching, reaming, drilling, tapping and threading, milling, sawing, and grinding. It provides information on the cutting fluids used in the machining of nickel alloys. The article also analyzes nontraditional machining methods that are suitable for shaping high-temperature, high-strength nickel alloys. These include electrochemical machining, electron beam machining, and laser beam machining.

Nickel and nickel-base alloys are vitally important to modern industry because of their ability to withstand a wide variety of severe operating conditions involving corrosive environments, high temperatures, high stresses, and combinations of these factors. This article discusses the mining and extraction of nickel and describes the uses of nickel. It discusses the categories of nickel-base alloys, including wrought corrosion-resistant alloys, cast corrosion-resistant alloys, heat-resistant alloys (superalloys), and special-purpose alloys. The article covers the corrosion resistance of nickel with the inclusion of varying alloying elements. It provides useful information on the behavior of nickel and nickel alloys in specific environments describes its corrosion resistance in certain acids, alkalis, and salts.

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.

The process of making assemblies of solid-solution and precipitation hardening groups of alloys and superalloys often requires welding of dissimilar metals, welding of diffusion-bonded materials, and sometimes weld overlay cladding and even thermal spraying that in turn requires special knowledge and treatments developed specifically for each material. This article emphasizes the special metallurgical welding considerations for welding solid-solution and precipitation hardening nickel alloys, cobalt alloys, and superalloys.

The properties of copper alloys occur in unique combinations found in no other alloy system. This article focuses on the major and minor alloying additions and their impact on the properties of copper. It describes major alloying additions, such as zinc, tin, lead, aluminum, silicon, nickel, beryllium, chromium, and iron. The article discusses minor alloying additions, including antimony, bismuth, selenium, manganese, and phosphorus. Copper alloys can be cast by many processes, including sand casting, permanent mold casting, precision casting, high-pressure die casting, and low-pressure die casting. The article provides information on the types of copper castings and tabulates the nominal chemical composition and mechanical properties of several cast alloys.

Addition of beryllium, up to about 2 wt″, produces dramatic effects in copper, nickel, aluminum, magnesium, gold, zinc, and other base metal alloys. This article provides information on the chemical composition, microstructure, heat treatment, fabrication characteristics, production steps and physical metallurgy of beryllium-copper, beryllium-nickel, and beryllium-aluminum alloy, and tabulates their mechanical, electrical and physical properties, and temper designations. It describes the important features of this alloy group, including information on safe handling. Additionally, the article presents examples of the beneficial properties of beryllium-copper alloys and quantifies some of the major reasons for their selection for particular applications.

Alloy cast irons are considered to be those casting alloys based on the iron-carbon-silicon system that contain one or more alloying elements intentionally added to enhance one or more useful properties. Alloy cast irons can be classified as white cast irons, corrosion-resistant cast irons, and heat-resistant cast irons. This article discusses abrasion-resistant chilled and white irons, high-alloy corrosion-resistant irons, and medium-alloy and high-alloy heat-resistant gray and ductile irons. The article outlines in a list the approximate ranges of alloy content for various types of alloy cast irons. The article explains the effects of alloying elements and the effects of inoculants. In most cast irons, it is the interaction among alloying elements that has the greatest effect on properties. Inoculants other than appropriate graphitizing or nodularizing agents are used rarely, if ever, in high-alloy corrosion-resistant or heat-resistant irons.

Ultrasonic welding (USW) is effectively used to join both similar and dissimilar metals with lap-joint welds. This article describes procedure considerations for the ultrasonic welding of specific material types. It reviews difficult-to-weld alloys, such as carbon and low-alloy steels, high-strength steels, and stainless steel, and provides information on the applications of weldable alloys such as aluminum alloys and copper alloys. The article concludes with a discussion on welding of dissimilar metal (nonferrous-to-nonferrous) combinations and its applications.

This article reviews the properties of cast steels that are specified for liquid corrosion service at temperatures above and below 650 deg C. Stainless steel castings are usually classified based on their resistance to corrosion and heat and generally fall into one category or the other. The article describes alternate methods for classifying cast stainless steels, one is based on grade designations, the other on microstructural analysis. It also addresses heat treatment, pointing out its similarities with the thermal processing of wrought materials, and establishes the importance of mechanical properties in material selection. The article presents information on the selection process and provides a detailed list of heat-resistant cast steels and alloys. It also includes key manufacturing characteristics to aid in foundry and welding-related decisions.

This article tabulates the nominal compositions for nickel and cobalt alloys. It illustrates the comparison of strain-hardening rates of a number of alloys in terms of the increase in hardness with increasing cold reduction. The forming practice for age-hardenable alloys and the lubricants used in the forming processes of nickel and cobalt alloys are also discussed. The article summarizes the modification of tools and dies used for cold forming other metals, as the physical and mechanical properties of nickel and cobalt alloys frequently necessitate it. It discusses forming techniques for these alloys and provides several examples of these techniques, which include shearing, blanking, piercing, deep drawing, spinning, explosive forming, bending, and expanding/tube forming.

Cryogenic temperatures cause many structural alloys to become brittle, which is an unacceptable condition in most structural applications and is rectified by optimizing the weld composition. Although nonmatching weld compositions are most appropriate, differences between the welds and parent material in terms of thermal contraction, corrosion, and other factors must be considered. This article discusses these differences and describes the effect of these factors on the choice of the weld filler metal. It also provides a detailed discussion on the effects of cryogenic services on mechanical properties of the parent metal.

Alloys based on ordered intermetallic compounds constitute a unique class of metallic material that form long-range ordered crystal structures below a critical temperature. Aluminides, a unique class of ordered intermetallic materials, possesses many attributes like low densities, high melting points, and good high-temperature strength that make them an attractive material for high-temperature structural application. This article discusses the properties, chemical composition, corrosion resistance, processing, fabrication, alloying effects and crystallographic data of nickel aluminides (Ni3Al and NiAl), iron aluminides (Fe3Al and FeAl) and titanium aluminides (alpha-2 alloys, orthorhombic alloys, and gamma alloys).

This article provides information on nickel alloying elements, and the heat treatment processes of various nickel alloys for applications requiring corrosion resistance and/or high-temperature strength. These processes are homogenization, annealing, solution annealing, solution treating, stabilization treatment, age hardening, stress relieving, and stress equalizing. Discussion of furnaces, fixtures, and atmospheres is included. Nickel alloys used for the heat treatment processes include corrosion-resistant nickel alloys, heat-resistant nickel alloys, nickel-beryllium alloys, special-purpose alloys such as nitinol shape memory alloys, low-expansion alloys, electrical-resistance alloys and soft magnetic alloys. Finally, the article focuses on heat treatment modeling for selecting the appropriate heat treatment process.

Alloy cast irons are casting alloys based on the Fe-C-Si system that contain one or more alloying elements added to enhance one or more useful properties. This article discusses the composition of different types of alloy cast iron, including white cast irons, corrosion-resistant cast irons, heat-resistant cast irons, and abrasion-resistant cast irons. It provides information on the effect of the alloying element on their high-temperature properties. The article also discusses the microstructure and mechanical properties of alloy cast irons.

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.

Nonferrous metals and alloys are widely used to resist corrosion. This article describes the corrosion behavior of the most widely used nonferrous metals, such as aluminum, copper, nickel, and titanium. It also provides information on several specialty nonferrous products that cannot easily be categorized by elemental base.

This article discusses the melting and pouring practices, heat treatment, and applications of different types of high-alloy graphitic iron, namely, high-silicon gray irons, high-silicon ductile irons, nickel-alloyed austenitic irons, austenitic gray irons, austenitic ductile irons, and aluminum-alloyed irons.

Cobalt finds its use in various applications owing to its magnetic properties, corrosion resistance, wear resistance, and its strength at elevated temperatures. This article discusses the mining and processing of cobalt and cobalt alloys. It describes the types of cobalt alloys, including wear-resistant alloys, high-temperature alloys, corrosion-resistant alloys, and special-purpose alloys. The article provides data on the chemical composition, mechanical properties, and physical properties of these alloys. Further, it provides information on the uses of cobalt in superalloys, cemented carbides, magnetic materials, low-expansion alloys, and high-speed tool steels.

Copper alloys are classified by the International Unified Numbering System designations to identify alloy groups by major alloying element. This article presents the designations and compositions of various copper alloys, such as brasses, nickel silvers, bronzes, beryllium coppers, and spinodal alloys. It discusses the fatigue testing of the copper alloys and tabulates the tensile and fatigue strengths of the copper alloys. The article schematically illustrates S-N curves for the solid-solution (non-aging) strengthened alloys. It concludes with a discussion on the role of microstructure in the fatigue performance of beryllium copper alloys.

Cast stainless steels are widely used for their corrosion resistance in aqueous media at or near room temperature and for service in hot gases and liquids at elevated temperatures. This article provides a comparison between cast and wrought stainless steels in terms of composition, microstructure and properties. It discusses the grade designations and compositions of cast stainless steels. The article describes the mechanical properties, applications, and corrosion characteristics of corrosion-resistant steel castings and heat-resistant steel castings.