Aluminum powders can be formed into components by several competing technologies, including powder metallurgy (PM), metal injection molding, powder forging, and additive manufacturing. This article explores PM methodologies that are being exploited to manufacture such components. It reviews emerging technologies that promise to offer exciting ways to produce aluminum parts. The article discusses the various steps involved in PM, such as powder production, compaction, sintering, repressing, and heat treatment. It provides information on aluminum production statistics and the wear-resistance applications of PM.

This article provides an overview of the compaction of metal powder in a rigid die and reviews the compaction characteristics of stainless steel powders, including green density, compressibility, green strength, apparent density, flow rate, and sintered density. It describes the influence of compaction characteristics of stainless steel powders in tool materials selection, lubrication, annealing, double pressing/double sintering, and warm compaction.

This article commences with a discussion on the qualitative and quantitative criteria for metal injection molding (MIM), including production quantities, shape complexity, material performance, and cost. It discusses geometric factors, such as surface finish, component size, and mass range, which help to identify a component for MIM. The article describes certain part features, including holes, undercuts, and flat faces. It concludes with a discussion on the common materials used in MIM; tensile properties of 17-4 PH stainless steel MIM, cast and wrought products; and attributes of the MIM process.

Friction materials are the components of a mechanism that converts mechanical energy into heat upon sliding contact. This article discusses the selection criteria, manufacturing process, and applications of friction powder metallurgy materials. It provides information on the manufacturing process of powder metallurgy friction materials through a process of mixing/blending, compacting, and sintering. The final machining that they undergo, to ensure that they meet dimensional specifications, is also discussed.

This article discusses the process details of metal powder injection molding of microcomponents and the powder particle characteristics of feedstock and property requirements of binders. It reviews important characteristics to be considered in the processing steps: venting, channel diameters, binder segregation, binder degradation, feedstock supply, temperature control, demolding, debinding, and sintering. Finally, the article provides information on powder injection molding mold-filling simulation and two-component powder injection molding, offering a method for high-volume production of microcomponents made of multifunctional materials.

Consolidation and shaping of grade powders is carried out using several methods, depending on the size, complexity, shape, and quantity of parts required. This article details the powder consolidation methods of carbide powders: uniaxial pressing, cold isostatic pressing, extrusion, green machining, and injection molding.

The powder metallurgy (PM) process is a relatively efficient and economic process that can be used to produce high quantities of aluminum components with a reasonable degree of precision and finds application in camshaft bearing cap (cam cap) production. The article discusses the production steps involved in cam cap manufacturing: powder production, compaction, sintering, repressing, and heat treatment. In addition, it reviews the R&D work involved in improving the structural properties of emerging aluminum alloy systems.

Metal injection molding (MIM) is a metalworking technology that has its origins as a commercial technology only dating back to the early 1970s. This article explores why the MIM is the preferred solution for many fabricated components. It illustrates the MIM components required for different end-use markets such as electronics and telecommunications, medical, automotive, power hand tools, industries, and firearms.

Warm compaction uses both powder heating and die heating to effect higher component densities, whereas warm die compaction uses only die heating to achieve higher density. This article explains the influences of green and sintered properties and pore-free density during compaction of materials. It provides information on the concept of pore-free density and process considerations: die heating and powder heating. The article concludes with a review of the tooling design for warm compaction.

Sintering is a thermal treatment process in which a powder or a porous material, already formed into the required shape, is converted into a useful article with the requisite microstructure. Sintering can be classified as solid-state, viscous, liquid-phase, and pressure-assisted (or pressure) sintering. This article provides information on the mechanisms and theoretical analysis of sintering and focuses on the types, mechanisms, process and microstructural variables, computer simulation, stages, and fundamentals of densification and grain growth of solid-state sintering and liquid-phase sintering. It describes the models for viscous sintering and the methods used in pressure-assisted sintering, namely, uniaxial hot pressing, hot isostatic pressing, sinter forging, and spark plasma sintering.

This article describes part selection, feedstock (powders and binders) characteristics and properties, tool design, and material and tooling for fabrication of metal powder injection molding (MIM) machines. It discusses the process parameters, operation sequence, molding machines, debinding techniques, consolidation (sintering) techniques, advantages, and limitations of MIM.

This article discusses continuum modeling, which is the most relevant approach in modeling grain growth, densification, and deformation during sintering. Continuum plasticity models are frequently used to describe the mechanical response of metal powders during compaction. The article illustrates the typical procedure for computer simulation for press and sinter process. It describes the procedure to obtain the material properties based on the generalized Shima-Oyane model. The article presents a wide variety of tests, accounting for data on the grain growth, densification, and distortion where these data help in the development of a constitutive model for sintering simulation. Finally, the article provides information on the simulation approaches used to optimize die compaction and sintering.

Powder metallurgy (PM) stainless steels, as with conventional PM steels, are often used in the as-sintered condition. In addition to cost considerations, minimization of postsinter handling and secondary operations is also preferred because it reduces the potential for contamination of the parts with particulates and residues, which can result in the appearance of surface rust. This article provides information on various secondary operations, including tumbling, re-pressing, resin impregnation, annealing or heat treating, brazing, machining, and welding. It describes those aspects relating to welding of PM stainless steels, specifically, the effects of density, residual porosity, and sintered chemistry on weldability. Further, the article investigates the influence the sintering atmosphere has on machinability, as well as differences created by the presence of residual porosity.

This article describes the unique aspects of cold isostatic pressing (CIP) in comparison with die compaction, for powder metallurgy parts. It details the components of CIP equipment, including pressure vessels, pressure generators, and tooling material. The article reviews the part shapes and their influence in determining tap density of the filled mold. It provides a discussion on process parameters, such as dwell time, depressurization rate, evaluation of green strength and density, and thermal processing, and illustrates a process flowchart for the production of CIP parts.

Powder metallurgy (PM) techniques are effective in making magnetically soft components for use in magnetic part applications. This article provides an account of the factors affecting magnetism, permeability, and hysteresis losses. It includes information on the magnetic properties of PM materials that are used in the magnetic part applications, namely, pure iron, phosphorus irons, ferritic stainless steels, 50 nickel-50 iron, and silicon irons. The article describes the factors that affect and optimize magnetic properties. It contains a table that lists the magnetic properties possible in metal injection molding parts. The article also discusses ferromagnetic cores used in alternating current applications and some permanent magnets, such as rare earth-cobalt magnets and neodymium-iron-boron (neo) magnets.

Powder metallurgy compacting presses usually are mechanically or hydraulically driven, but they can incorporate a combination of mechanically, hydraulically, and pneumatically driven systems. This article provides a comparison of mechanical and hydraulic presses based on the cost, production rate, and machine overload protection. The article lists the classification of powder metallurgy parts based on complexity of shapes as suggested by the Metal Powder Industries Federation, such as Class I parts, Class II parts, Class III parts, and Class IV parts. It describes rigid tooling compaction and details the powder-fill ratio considerations for these classes. The article elaborates on the types of tooling systems and presses used for these classes. Some important factors and components used in designing a tool are also described. Finally, the article considers tool materials, including punches, core rods, and punch clamp rings.

Powder metallurgy (PM) processes include press and sinter hardening, metal injection molding, powder forging, hot isostatic pressing, powder rolling, and spray forming. This article provides an overview of PM processing methods and general considerations of heat treatment of PM parts that are case-hardened to obtain higher hardness, wear, fatigue, and impact properties. It describes the effects of porosity on heat treatment, alloy content on PM hardenability, and starting material on homogenization of PM steels. The article describes the properties, following heat treatment, of low-alloy steels tempered at 175 ºC for one hour, and lists recommended quench and temper parameters to achieve good wear resistance and core strength based on different ranges of porosity.

This article presents the governing equations and methodologies to model the press and sinter powder metallurgy, including continuum, micromechanical, multiparticle, and molecular dynamics approaches. It describes the constitutive relation for compaction and sintering. The article discusses the experimental determination of material properties and simulation verification for compaction and sintering. It reviews the use of modeling and simulation of press and sinter powder metallurgy, including gravitational distorting in sintering, compaction optimization, sintering optimization, and coupled press and sinter optimization.

This article focuses on the axisymmetric 2.5-dimensional approach used in metal powder injection molding (PIM) simulations. It describes three stages of PIM simulations: filling, packing, and cooling. The article discusses the process features of numerical simulation of PIM, such as filling and packing analysis, cooling analysis, and coupled analysis between filling, packing, and cooling stages. It explains the experimental material properties and verification for filling, packing, and cooling stages in the PIM simulations. The article presents simulation results from some of the 2.5-dimensional examples to demonstrate the usefulness of the computer-aided engineering analysis and optimization capability of the PIM process.