This chapter provides a qualitative overview of powder preparation technologies including milling, mechanical alloying, electrolytic dissolution, metal oxide reduction, solid-state reactive synthesis, and gas, water, and centrifugal atomization. It discusses the general implementation of each process, the materials for which they are used, and the powder characteristics that can be achieved.

This chapter covers various consolidation techniques used in powder metallurgy, including laser sintering (pressureless sintering), hot pressing, high-pressure torsion, microwave sintering, spark plasma sintering, and pulse plasma sintering. It also discusses the effect of milling parameters on mechanically alloyed powders, their consolidation characteristics, and the properties of bulk components.

This chapter discusses the growing role of powder metallurgy in the production of intermetallic, Heusler, and high-entropy alloys. It reviews the challenges of producing these materials by conventional methods and the advantages of sinter-based PM techniques. It explains why PM processes are better suited for complex materials than casting and compares the properties of intermetallic, Heusler, and high-entropy alloys prepared by casting and powder-metal techniques.

This chapter provides an introduction to powder processing of binders and polymers. It sets the context for the remainder of the book by providing an overview of the topics discussed in the subsequent chapters and by providing introduction to powder-binder fabrication and customization of feedstock and describing the challenges in component production. The chapter also summarizes alphabetically a few key concepts in powder-binder processing.

This chapter introduces the key powder fabrication attributes to assist in the identification of the right powders for an application. First, it describes the characteristics of engineering powders such as particle size distribution, powder shape and packing density, surface area, powder flow and rheology, and chemical analysis. The chapter then describes the general categories of powder fabrication methods, namely mechanical comminution, electrochemical precipitation, thermochemical reaction, and phase change and atomization. It provides information on the two largest contributors to powder price, namely raw material cost and conversion cost. The applicability of various processes to specific material systems is mentioned throughout this chapter.

This chapter is a detailed account of various attributes related to mixing and testing of powder-binder feedstocks. Mixing parameters and their effects on feedstock properties is discussed. The attributes reviewed include mixture homogeneity, wetting, powder-binder ratio, feedstock density, elastic modulus, rheological behavior, particle size, formulation control, feedstock mixing, and feedstock properties. The chapter also provides information on the processes involved in feedstock preparation and testing.

This chapter provides details on powder-binder processing for three materials, namely precipitation-hardened 17-4 PH stainless steel, cemented carbides, and alumina. The types of powders, binders, feedstock, shaping processes, debinding, sintering cycles, compositions, microstructure, distortion, postsintering treatments, and mechanical properties are presented for each. The shaping options include powder-binder approaches such as binder jetting, injection molding, extrusion, slip and slurry casting, centrifugal casting, tape casting, and additive manufacturing. Sintering options are outlined with respect to attaining high final properties.

This chapter includes a comprehensive set of definitions used in powder-binder processing.

Increasing growth of high-pressure cold spraying applications on the industrial scale have forced global powder producers to face this challenge and develop specific powders for cold spray applications. This chapter provides information on the properties, classification, characteristics, manufacturing, and procedures for packaging of powders specific to cold spray applications.

This chapter describes the processes, applications, and limitations of forming and shaping various materials. It discusses bulk forming, hot working, cold working, sheet forming, and polymer and powder processing.

Beryllium is an extraordinary metal with an unusual combination of physical and mechanical properties. It has low density, high stiffness, and excellent dimensional stability. It is also transparent to x-rays and can be machined to extremely close tolerances. This chapter discusses the properties, compositions, and processing characteristics of beryllium and its alloys. It provides information on powder production and consolidation, commercial designations and grades, wrought products, and forming processes. It also discusses the issue of corrosion, the use of protective treatments and coatings, and health and safety concerns.

This chapter describes the processes involved in alloy production, including melting, casting, solidification, and fabrication. It discusses the effects of alloying on solidification, the formation of solidification structures, supercooling, nucleation, and grain growth. It describes the design and operation of melting furnaces as well as melting practices and the role of fluxing. It also discusses casting methods, nonferrous casting alloys, and atomization processes used to make metal powders.

This chapter describes the processes involved in the fabrication of wrought and cast metal products. It discusses deformation processes including bending and forming, material removal processes such as milling, cutting, and grinding, and joining methods including welding, soldering, and brazing. It also discusses powder consolidation, rolling, drawing and extrusion, and common forging methods.

Stainless steel powders are usually made by water or gas atomization. This chapter describes both processes and the properties and characteristics of the powders they produce. It also discusses secondary processes, including drying, screening, annealing, and lubricating, and the effects of iron contamination on corrosion resistance.

Gas turbine disks made from nickel-base superalloys are often produced using powder metallurgy (P/M) techniques because the alloy compositions normally used are difficult or impractical to forge by conventional methods. This chapter discusses the P/M process and its application to superalloys. It describes the gas, vacuum, and centrifugal atomization processes used to make commercial superalloy powders. It explains how the powders are consolidated into preforms or billets using hot isostatic pressing, extrusion, or a combination of the two. It also provides information on spray forming and consolidation by atmospheric pressure, and includes a section on powder-based disk components, where it discusses the general advantages of P/M as well as the effects of inclusions, carbon contamination, and the formation of oxide and carbide films due to prior particle boundary conditions. The chapter concludes with a detailed discussion on mechanically alloyed superalloy compositions, the product forms into which they are made, and some of the applications where they are used.

This article discusses the composition, structure, and properties of iron-nickel-, nickel-, and cobalt-base superalloys and the effect of major alloying and trace elements. It describes the primary and secondary roles of each alloying element, the amounts typically used, and the corresponding effect on properties and microstructure. It also covers mechanical alloying and weldability and includes nominal composition data on many wrought and cast superalloys.