Search Results for powder consolidation

This chapter provides an overview of sintering techniques and the microstructures and properties that can be achieved in different material systems. It covers conventional furnace sintering, microwave and laser sintering, hot and hot-isostatic pressing, and spark plasma sintering. It describes the advantages and disadvantages of each method, the mechanisms involved, and the effect of sintering parameters on the density, grain size, and mechanical properties of titanium and tungsten heavy alloys, stainless steel, cemented carbides, ceramics, composites, and rare earth magnets.

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.

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 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 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.

Powder metallurgy plays a central role in the production of nearly all beryllium components. This chapter describes the primary steps in the powder metal process and the work that has been done to improve each one. It explains how beryllium powders are made and how they are consolidated prior to sintering. It also compares and contrasts the properties of beryllium products made using different methods and provides composition and particle size data on commercially available powders.

This chapter covers the basic steps of the powder metallurgy process, including powder manufacture, powder blending, compacting, and sintering. It identifies important powder characteristics such as particle size, size distribution, particle shape, and purity. It compares and contrasts mechanical, chemical, electrochemical, and atomizing processes used in powder production, discusses powder treatments, and describes consolidation techniques along with secondary operations used to obtain special properties or improve dimensional precision. It also discusses common defects such as ejection cracks, density variations, and microlaminations.

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 discusses the compositions, properties, and applications of nonferrous metals, including zirconium, hafnium, beryllium, lead, tin, gold, silver, and platinum group metals. It also addresses fusible alloys and provides melting temperatures for several compositions.

This chapter discusses the advantages and disadvantages of producing titanium parts using powder metallurgy (PM) techniques. It compares the typical properties of wrought, cast, and PM titanium alloy products, addresses various manufacturing challenges, and describes several consolidation and shaping processes along with associated property data.

This chapter examines the microstructure of metallic components produced by casting and compares them with microstructures achieved by means of powder metallurgy. It shows how metals and alloys obtained by various processing routes differ in terms of grain size, secondary phases, oxide and carbide dispersions, porosity, dendritic formation, and properties such as hardness, toughness, tensile strength, and yield strength.

This chapter discusses the types of fibers and matrix materials used in ceramic matrix composites and the role of interfacial coatings. It describes the methods used to produce ceramic composites, including powder processing, slurry infiltration and consolidation, polymer infiltration and pyrolysis, chemical vapor infiltration, directed metal oxidation, and liquid silicon infiltration.

Precipitation hardening is used extensively to strengthen aluminum alloys, magnesium alloys, nickel-base superalloys, beryllium-copper alloys, and precipitation-hardening stainless steels. This chapter discusses two types of particle strengthening: precipitation hardening, which takes place during heat treatment; and true dispersion hardening, which can be achieved by mechanical alloying and powder metallurgy consolidation. It provides information on the three steps of precipitation hardening of aluminum alloys: solution heat treating, rapid quenching, and aging.

This chapter reviews some of the differences between powder metallurgy and additive manufacturing and explains how they influence the microstructure and properties of various alloys and the formation of defects in manufactured parts.

This chapter discusses thermoplastic composite fabrication processes and related equipment and procedures. The discussion covers consolidation and thermoforming operations as well as joining methods.