Browse Topic: Powder metallurgy
The initial powder used for the manufacturing of NdFeB permanent magnets is usually prepared through rapid cooling, either by melt spinning or strip casting. The powders produced by these two methods are suitable for different applications: while melt-spun powder is a good initial material for bonded and hot-deformed magnets, strip-cast powder is normally used for sintered magnets. To investigate the suitability of using strip-cast powder to manufacture hot-deformed magnets, NdFeB powder prepared by strip casting was hot pressed (without particle alignment) and compared with melt-spun powder prepared under the same conditions (700 °C, 45 MPa, 90 min). Although the processing parameters are the same (pressed in the same mold), the magnetic properties of the magnets made from the two powders are significantly different. Surprisingly, the magnet made from the strip-cast powder (after ball milling) shows comparable magnetic properties to those of isotropic magnets, with coercivity (HcJ) of
A novel sintering method of bridging the two mechanically polished and oriented single-crystals together face-to-face in a non- environmental controlled atmosphere to fabricate the bicrystal substrate of NaCl of macroscopic thickness, with a common zone axis and having planarity over large areas, has been developed. Epitaxial [001] bicrystalline thin face-centered cubic (fcc) metal film of surface-reactive metal-containing tilt grain boundary across the interface is first grown in high vacuum directly by flash deposition on initially fabricated [001] oriented bicrystalline substrate of NaCl. The [001] tilt boundary, thus produced, and is examined by electron microscopy to characterize grain boundary morphology and structure. The findings of some preliminary investigations are then presented. A distinct atomic structure is observed for 310 and 210 inclination. Both HAADF-STEM and Diffraction images reveal that such fabricated high-angle grain boundary accommodates minor deviations from
This specification covers virgin, unfilled polytetrafluoroethylene (PTFE) in the form of molded rods, tubes, and shapes. This specification does not apply to product over 12 inches (305 mm) in dimension parallel to the direction of applied molding pressure, rods under 0.750 inch (19.05 mm) in diameter, and tubes having wall thickness under 0.500 inch (12.70 mm).
This specification covers two types of virgin, unfilled polytetrafluoroethylene (PTFE) in the form of molded rods, tubes, and shapes. This specification does not apply to product over 12 inches (305 mm) in length, rods under 0.750 inch (19.05 mm) in diameter, and tubes having wall thickness under 0.500 inch (12.70 mm).
Recent advances in both alloy development and additive manufacturing have enabled the production of ultrahigh-strength steels in nearnet shape parts. Army Research Laboratory, Aberdeen Proving Ground, Maryland Ultrahigh-strength steels are traditionally defined as those steels with a minimum yield strength of approximately 1380 MPa. Notable examples of steels in this category include AISI 4130, AISI 4140, and AISI 4340. In many cases, maximizing the performance of these alloys requires a rather complex approach that involves a series of tempering, annealing, or stress-relieving treatments. As a result, they are produced using a variety of traditional processing methods such as casting, rolling, extrusion, or forging. These traditional methods - combined with the ultrahigh strength of the steels - often meant that the production of complex, near-net shape parts of high quality was quite difficult. In addition, these production methods often entailed repetitive treatments or long
General Motors (GM) is working towards a future world of zero crashes, zero emissions and zero congestion. It’s “Ultium” platform has revolutionized electric vehicle drive units to provide versatile yet thrilling driving experience to the customers. Three variants of traction power inverter modules (TPIMs) including a dual channel inverter configuration are designed in collaboration with LG Magna e-Powertrain (LGM). These TPIMs are integrated with other power electronics components inside Integrated power electronics (IPE) to eliminate redundant high voltage connections and increase power density. The developed power module from LGM has used state-of-the art sintering technology and double-sided cooled structure to achieve industry leading performance and reliability. All the components are engineered with high level of integration skills to utilize across TPIM variants. Each component in the design is rigorously analyzed and tested from component to system levels to ensure high
This specification covers a corrosion-resistant steel, consolidated by hot isostatic pressing (HIP) product from prealloyed powder, in the form of bars, wire, forgings, and forging stock.
Powder metallurgy of 3065IS temperature and strain rate were only two of the variables used to investigate the higher permeability of an iron alloy. A strain rate vs. stress plot revealed a critical value. This demonstrated that the functioning of the alloy was comparable to that of other materials in its class. We used a transmission electron microscope to examine the microstructure of routinely twisted materials to determine particle characteristics and precipitate distribution. This allowed us to gain a better understanding of the internal workings of materials. Using constitutive equations, we investigated the link between temperature and stress. This study's findings were incorporated into equations describing the material's high thermal behaviour, and a modified version of the cosec equation was used to analyse this reliance. Effective stress was defined as the distinction between actual stress and a present limit. It has been shown that the presence of ferrous particles and
Sintered parts mechanical properties are very sensitive to final density, which inevitable cause an enormous density gradient in the green part coming from the compaction process strategy. The current experimental method to assess green density occurs mainly in set up by cutting the green parts in pieces and measuring its average density in a balance using Archimedes principle. Simulation is the more accurate method to verify gradient density and the main benefit would be the correlation with the critical region in terms of stresses obtained by FEA and try to pursue the optimization process. This paper shows a case study of a part that had your fatigue limit improved 1000% using compaction process simulation for better optimization.
This specification covers a titanium alloy in the form of compacts produced by pressing and sintering a blend of elemental titanium powder and aluminum-vanadium alloy powder (see 8.6).
A Penn State-led team of researchers have created a new process to fabricate large perovskite devices that is more cost- and time-effective than previously possible — and may accelerate future materials discovery.
This specification covers an aluminum-beryllium alloy in the form of bars, rods, tubing, and shapes consolidated from powder by extrusion.
This specification covers a premium aircraft-quality, high-alloy steel gas-atomized and HIP-consolidated in the form of bars, wire, forgings, and forging stock.
This specification covers a premium aircraft-quality, high-alloy tool steel gas-atomized and HIP-consolidated in the form of bars, wire, forgings, and forging stock.
This specification covers a premium aircraft-quality, high-alloy tool steel gas-atomized and HIP consolidated in the form of bars, wire, forgings, and forging stock.
This specification covers a premium aircraft-quality, high-alloy steel gas-atomized and HIP-consolidated in the form of bars, wire, forgings, and forging stock.
This specification covers discontinuously reinforced aluminum alloy (DRA) metal matrix composites (MMC) made by mechanical alloying of 6061B aluminum powder and SiC particulate, which is then consolidated by Hot Isostatic Pressing (HIP) into shapes between 12 to 100 square inches (0.008 to 0.065 m2), inclusive, cross-section. Tensile property response to heat treatment has been demonstrated on samples of 1 square inch (645 mm2) maximum cross section (see 8.9).
This specification covers a polyimide plastic in the form of isostatically molded rod, bar, and tube, unidirectionally molded plaque, and direct formed parts.
This specification covers a titanium alloy in the form of prealloyed powder.
This specification covers a titanium alloy in the form of prealloyed powder.
This specification prescribes process requirements for batch processing of used, metal powder originating from an existing additive manufacturing process workflow for reuse in subsequent additive manufacturing of aerospace parts in non-closed loop additive manufacturing machines. Such powders may be pre-alloyed or commercially pure. This specification is not limited to a specific additive manufacturing process workflow as the originating source of material to be reused. It is intended to define those procedures and requirements necessary to achieve required cleanliness and performance of metal powder feedstock to be reintroduced into the same additive manufacturing process from which such powder originated. This specification is intended to be used in conjunction with relevant AMS powder specifications and AMS process specifications for additive manufacturing. Unless otherwise specified, powder prepared for reuse following this specification is intended to be conforming in physical and
In the early days, there were significant limitations to the build size of laser powder bed fusion (L-PBF) additive manufacturing (AM) machines. However, machine builders have addressed that drawback by introducing larger L-PBF machines with expansive build volumes. As these machines grow, their size capability approaches that of directed energy deposition (DED) machines. Concurrently, DED machines have gained additional axes of motion which enable increasingly complex part geometries—resulting in near-overlap in capabilities at the large end of the L-PBF build size. Additionally, competing technologies, such as binder jet AM and metal material extrusion, have also increased in capability, albeit with different starting points. As a result, the lines of demarcation between different processes are becoming blurred. Internal Boundaries of Metal Additive Manufacturing: Future Process Selection examines the overlap between three prominent powder-based technologies and outlines an approach
Using a layer-by-layer approach during the additive manufacturing (AM) process, laser powder bed fusion technology (LPBF) can produce finished components directly from metal powder alloys with minimal post-processing required. Intricate designs can be realized in the final part directly from printing, allowing for greater freedom of design than when using traditional manufacturing technologies. In some cases, this approach reduces the complexity and number of parts in component assemblies. The powder-to-part manufacturing process, along with the increased freedom of design, makes additive manufacturing a disruptive process compared to traditional manufacturing techniques.
Conventional approaches for recycling metal waste are energy-intensive and some also generate environmentally harmful byproducts such as ammonia and methane during aluminum recycling. To address this challenge, researchers demonstrated an eco-friendly technique to convert aluminum and magnesium waste into high-value, multifunctional aerogels. This upcycling method could be applied to all types of metal waste such as metal chips and electronic waste.
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