This article discusses the general purpose of alloying and identifies some of the material properties and behaviors that can be improved by adding various elements to the base metal. It explains how alloying can make metals stronger and more resistant to corrosion and wear as well as easier to cast, weld, form, and machine. It also discusses some of the alloying techniques that have been developed to address problems stemming from dissimilarities between the base metal and alloying or inoculate material.

This chapter discusses the basic principles of alloying and their practical application in the production of titanium mill products and engineered parts. It begins with a review of the atomic and crystal structure of titanium and the conditions for interstitial and substitutional alloying. It then describes the different classes of alloying elements, their effect on mechanical properties and behaviors, and their influence on phase transitions and transformations. The chapter also discusses the role of intermetallic compounds and their effect on crystal structure and creep behavior.

This chapter describes the most effective ways to improve the corrosion resistance of sintered stainless steels, including increasing alloy content, optimizing the sintering process, and the use of surface treatments and modifications.

This chapter discusses the composition, properties, and uses of the most common beryllium alloys and composites. It provides information on beryllium-aluminum, beryllium-copper, and beryllium-titanium as well as beryllium-antimony and beryllium-iron systems.

Stainless steels derive their name from their exceptional corrosion resistance, which is attributed to their finely tuned compositions. This chapter discusses the alloying elements used in stainless steels and the some of the processing challenges they present. One of the biggest challenges is that stainless steels cannot be hardened by heat treatment. As a result, they are highly sensitive to processing-induced defects and the formation of detrimental phases. The chapter explains how alloy design, phase equilibria, microstructure, and thermomechanical processing can be concurrently optimized to produce high-quality austenitic, ferritic, and duplex stainless steels.

This article discusses the role of alloying in the production and use of low-expansion alloys such as iron-nickel (Invar), iron-nickel-chromium (Elinvar), and iron-nickel-cobalt (Super-Invar and Kovar). It explains how the coefficient of thermal expansion varies with nickel content and how it can be tailored, along with other properties, through appropriate alloying adjustments. The article also discusses the effect of alloying on Incoloy and Pyromet, which are classified as high-strength, controlled-expansion alloys.

This article discusses the compositions, structures, and properties of the most common grades of soft magnetic metals and permanent magnet alloys. It explains how alloying additions and impurities affect the magnetic properties of these materials, which include commercially pure and phosphorus irons, low-carbon and silicon steels, ferritic stainless steels, and nickel-iron and iron-cobalt alloys.

This chapter discusses the factors influencing the corrosion resistance of bulk materials, namely alloying, metallurgical factors, and mechanical treatments.

Heat treatment of steel involves a number of processes to condition the microstructure and obtain desired properties. This includes various methods namely, annealing, normalizing, and hardening by quenching and tempering. This chapter focuses on general heat treatment procedures and the applications of particular types or grades of carbon and low-alloy steels. The discussion covers carbon steel classification for heat treating, tempering of quenched carbon steels, and austempering of steel. In addition, the chapter discusses the effects of alloying and hardenability on steel and provides information on martempering of steel.

This chapter discusses the corrosion behavior of titanium, the types of corrosion that can occur, and the effect of alloying on corrosion resistance. It explains that, due to its tenacious oxide film, titanium has excellent corrosion resistance in oxidizing environments and that the resistance can be extended into the “reducing-acid” region by adding a small amount of palladium. It describes how different grades of titanium respond to different forms of attack, including uniform, crevice, and galvanic corrosion. It also identifies applications where corrosion is often a concern.

Nickel and nickel alloys have an excellent combination of corrosion, oxidation, and heat resistance, combined with good mechanical properties. Nickel alloys can be divided into alloys that combine corrosion and heat resistance, superalloys for high-temperature applications, and special nickel alloys. Corrosion- and heat-resistant nickel alloys include commercially pure and low-alloy nickels, nickel-copper alloys, nickel-molybdenum and nickel-silicon alloys, nickel-chromium-iron alloys, nickel-chromium-molybdenum alloys, and nickel-chromium-iron-molybdenum-copper alloys. Special nickel alloys include electrical-resistance alloys, low-expansion alloys, magnetically soft alloys, and shape memory alloys. This chapter discusses the metallurgy, nominal composition, properties, applications, advantages, and disadvantages of these alloys. It also provides information on cobalt wear-resistant alloys and cobalt corrosion-resistant alloys.

The term heat treatable alloys is used in reference to alloys that can be hardened by heat treatment, and this chapter briefly describes the major types of heat treatable nonferrous alloys. The discussion provides a general description of annealing cold-worked metals and describes some of the common nonferrous alloys that can be hardened through heat treatment. The nonferrous alloys covered include aluminum alloys, cobalt alloys, copper alloys, magnesium alloys, nickel alloys, and titanium alloys.

Aluminum casting alloy compositions parallel those of wrought alloys in many respects. However, because work hardening plays no significant role in the development of casting properties, the use and purposes of some alloying elements differ in casting alloys versus wrought alloys. This chapter provides information on specifications and widely used designation systems and alloy nomenclature for aluminum casting alloys. It describes the composition of seven basic families of aluminum casting alloys: aluminum-copper, aluminum-silicon-copper, aluminum-silicon, aluminum-silicon-magnesium, aluminum-magnesium, aluminum-zinc-magnesium, and aluminum-tin. The chapter discusses the effects of alloying elements on the properties of cast aluminum. It provides information on various alloys that are grouped with respect to their applications or major performance characteristics.

Alloy steels are alloys of iron with the addition of carbon and one or more of the following elements: manganese, chromium, nickel, molybdenum, niobium, titanium, tungsten, cobalt, copper, vanadium, silicon, aluminum, and boron. Alloy steels exhibit superior mechanical properties compared to plain carbonsteels as a result of alloying additions. This chapter describes the beneficial effects of these alloying elements in steels. It discusses the mechanical properties, nominal compositions, advantages, and engineering applications of various classes of alloy steels. They are low-alloy structural steels, SAE/AISI alloy steels, high-fracture-toughness steels, maraging steels, austenitic manganese steels, high-strength low-alloy steels, dual-phase steels, and transformation-induced plasticity steels.

Nickel-base alloys used for low-temperature aqueous corrosion are commonly referred to as corrosion-resistant alloys (CRAs), and nickel alloys used for high-temperature applications are known as heat-resistant alloys, high-temperature alloys, or superalloys. The emphasis in this chapter is on the CRAs and in particular nickel-chromium-molybdenum alloys. The chapter provides a basic understanding of general welding considerations and describes the welding metallurgy of molybdenum-containing CRAs and of nickel-copper, nickel-chromium, and nickel-chromium-iron CRAs. It discusses the corrosion behavior of nickel-molybdenum alloys and nickel-chromium-molybdenum alloys. Information on the phase stability and corrosion behavior of nickel-base alloys is also included.

This chapter is dedicated mostly to the metallurgical effects on the corrosion behavior of corrosion-resistant alloys. It begins with a section describing the importance of alloying elements on the corrosion behavior of nickel alloys. The chapter considers the metallurgical effects of alloy composition for heat-resistant alloys, nickel corrosion-resistant alloys, and nickel-base alloys. This chapter also discusses the corrosion implications of changing the alloy microstructure via solid-state transformation, second-phase precipitation, or cold work. It concludes with a comparison of corrosion behavior between cast and wrought product forms.

This chapter is dedicated mostly to the metallurgical effects on the corrosion behavior of corrosion-resistant alloys. It begins with a section describing the importance of alloying elements on the corrosion behavior of nickel alloys. The chapter considers the metallurgical effects of alloy composition for heat-resistant alloys, nickel corrosion-resistant alloys, and nickel-base alloys. This chapter also discusses the corrosion implications of changing the alloy microstructure via solid-state transformation, second-phase precipitation, or cold work. It concludes with a comparison of corrosion behavior between cast and wrought product forms.

This chapter describes the designations of carbon and low-alloy steels and their general characteristics in terms of their response to hardening and mechanical properties. The steels covered are low-carbon steels, higher manganese carbon steels, boron-treated carbon steels, H-steels, free-machining carbon steels, low-alloy manganese steels, low-alloy molybdenum steels, low-alloy chromium-molybdenum steels, low-alloy nickel-chromium-molybdenum steels, low-alloy nickel-molybdenum steels, low-alloy chromium steels, and low-alloy silicon-manganese steels. The chapter provides information on residual elements, microalloying, grain refinement, mechanical properties, and grain size of these steels. In addition, the effects of free-machining additives are also discussed.