Metal binder jetting (BJT) is a promising metal Additive Manufacturing (AM) process as it can form complex geometries out of metal powder without the use of direct heat input, at high production rates and low manufacturing cost. In this work, metal binder jetting is presented as a fabrication process for automotive vehicle components, specifically interior safety applications. The component is a customer-facing automotive part requiring cosmetic surface finish and properties critical for passenger vehicle safety. It is the first sinter-based additively manufactured safety-critical part in a production vehicle. The development of AM intended designs and post-processing approaches using metal binder jetting as a fabrication method were investigated and successfully implemented into production. To validate the components, multiple material tests and application-specific tests were performed. Many factors had to be taken into consideration to match the level of standardization and quality control required for automotive production. These components have passed all quality requirements to achieve Production Part Approval Process (PPAP) and are installed in production vehicles.
Vacuum sintering is a proven method to improve mechanical properties while eliminating oxidation potential and atmosphere contamination in powder metallurgy (PM) components. Recent progress in vacuum sintering technologies have made this sintering method an attractive manufacturing process for PM materials aiming for property improvement, and for the versatility and flexibility to control process parameters. Vacuum sintering furnaces are available in both batch and continuous configurations, with most furnaces utilizing the batch configuration. However, interest in continuous vacuum furnaces continues to grow due to increased production requirements and the advantages over batch vacuum furnaces for processing of larger production quantities. Currently, systematic studies are lacking to compare vacuum sintering processes with conventional sinter methods for PM steels. In this paper, the sintering responses of a chromium-based sinterhardenable prealloyed steel were examined in a vacuum sintering furnace at conventional and high temperature, and with different cooling rates.
The development of commercially available niobium (Nb) base alloy powders for additive manufacturing (AM) opens completely new opportunities to produce high-temperature, high-performance components that are particularly interesting for aerospace applications. It is crucial to comprehend the entire workflow, which ranges from powder production and characterization to the determination of optimal process parameters. Insights into the preparation, characterization, and processing of Nb-base alloy powders using metal AM techniques are presented in detail. Nb-base alloys such as C-103 and FS-85 are emerging as promising candidates to improve the capabilities of additive manufacturing, particularly in aerospace applications. What sets Nb-base alloys apart from common materials are their exceptional properties-remarkably low density combined with high thermal conductivity, and outstanding mechanical strength at high temperatures. These properties make such alloys a superior alternative to traditional Ni- and Co-base materials, particularly in environments with temperatures surpassing 1,050 degrees C. While C-103 has become firmly established in conventional manufacturing, there is still no experience with conventional molding for FS-85, which is currently the focus of interest due to its extraordinary strength at elevated temperatures. The commercial availability of FS-85 alloy powders for additive manufacturing opens exciting possibilities for producing high-performance components with complex geometries.
Details are provided on the alloys (W-Ni-Cu-Mn), sample fabrication, processing cycle, and density results from liquid-phase sintering experiments performed on the International Space Station. The alloys ranged from 70-90 wt.% W. The matrix Ni:Cu:Mn ratio was adjusted to vary the tungsten solubility, evident via dihedral angle changes. Sintered samples were retrieved after time- temperature combinations ranging from 6 minutes at 1,175 degrees C to 67 minutes at 1,205 degrees C (or slightly higher). Post-flight analysis focused on sintered relative density, which ranged 66 to 94%. The sintered microstructure evidences grain growth and formation of oxides, often with pores attached to the oxide. The oxides are attributed to in situ reaction of oxygen, initially dissolved in the powder, released by dissolution into the liquid to react with manganese. The microgravity sintered density is different from that obtained from ground experiments and incomplete densification with pore agglomeration being typical.
Hot isostatic pressing (HIP) treatments are typically applied to some additively manufactured (AM) parts to seal internal porosity and improve performance and reliability of the component. Nickel-based superalloys require multiple heat treatments including stress relief, HIP, solution anneal, and a two-step ageing treatment to produce a microstructure that can withstand demanding environments. AM offers many advantages over conventional manufacturing techniques, but multiple post-processing steps often make the commercial case prohibitive. As such, there is an ongoing demand within AM to simplify and consolidate the process chain to aid in driving adoption. In this work, Inconel 718 parts were manufactured by laser powder-bed-fusion (PBF-LB), subjected to a range of hot isostatic pressing (HIP) and heat treatments, then machined into a geometry that allows high-throughput tension testing, thereby removing the variables of surface roughness and contour microstructures. The goal of this study is to simplify heat-treatment routes while maintaining satisfactory tensile performance by leveraging modern HIP technology. Recent advancements in HIP equipment now offer the ability to integrate HIP and heat treatment in the HIP furnace with the aid of controllable high-speed cooling and in-HIP quenching and is referred to as High Pressure Heat TreatmentTM. The tailored heat-treatment avenues will attempt to accomplish the following: avoid separate heat-treatment steps such as stress relief and solution annealing by consolidating in the HIP, minimizing the number of ageing steps, minimizing grain growth, sealing porosity with a minimum HIP pressure, and avoiding recrystallization to retain dislocation cell networks for optimum productivity and performance. Preliminary experiments will be shared capturing promising results.
Lamination sheet steel used for magnetic stator cores have excellent magnetic properties within individual sheets. The comparison of these individual sheet properties, such as maximum saturation and permeability, with powder-based soft magnetic composites appears unfavorable for SMC use. The properties of lamination assemblies, however, is lower than individual sheets due to stacking factor and the presence of insulation layers. Further, it is commonly understood that these stacks tend to work best at lower frequency, whereas SMC is more suited to higher frequency. The number of direct comparisons of SMC and lamination steel stacks is limited in the literature, resulting in broad generalizations. In this study, test rings made with assemblies of 2 lamination steel grades and 2 grades of SMC will be evaluated under different test conditions. The direct comparison will enable users of the technology to understand the benefits and limitations of each approach, leading to the best engineering solutions.
The materials and test method standards published by the Metal Powder Industries Federation (MPIF) are subject to periodic review. There have been five new editions of MPIF Standard 35-SP Materials Standards for PM Structural Parts in the last ten years and four of Standard Test Methods for Metal Powders and Powder Metallurgy Products. The maintenance of these standards and the development of new standards is the responsibility of the MPIF Standards Committee along with the Metal Powder Producers Association (MPPA) Standards Committee. Insight will be provided into some of the key changes made during recent years along with the reasoning behind the changes. Plans for future standards development activities will also be discussed.
Tension testing of heat- treated powder metallurgy (PM) materials has been an ongoing problem. The conventional flat, unmachined (dog-bone) test specimens used for testing as-sintered PM materials become more difficult to grip as the materials get harder and stronger. Historical attempts to resolve this problem will be reviewed and the evolution of machined round tension test specimens summarized. There has been concern for some time that the published heat-treated tensile strengths of PM copper steels have been too low. The details of a new testing program conducted by the Metal Powder Industries Federation (MPIF) Standards Committee are presented, including the revised "typical" ultimate tensile strength values for heat-treated PM copper steels determined for publication in MPIF Standard 35-SP, Material Standards for Powder Metallurgy (PM) Structural Parts.
PowderMet2024 and AMPM2024 will take place in Pittsburgh, June 16-19. residents to attend, and MPIF has announced special offers to make attendance even more attractive. I am currently reviewing the technical program and planning which sessions to attend. I look forward to seeing many friends in Pittsburgh in June. his expertise in the theory of sintering. He has been a member of the Technical Program Committee for many PM conferences. the major challenges and opportunities for the powder metallurgy (PM) industry arising from the shift in the automotive industry from internal combustion engines to electric motors, supply-chain localization, and sustainability. Trends are highlighted from the perspective of powder producers, equipment makers, and the producers of pressed-and-sintered, additively manufactured, and metal injection molded parts. The resilience of the PM industry and the global improvement for most economies, has resulted in a more optimistic environment that is expected to spur growth for the PM sector in the coming years. performance of a promising alloy for binder-jet processing that can match the properties of an M4 tool steel at a lower cost through the use of less expensive testing in, "A Review of Rotating Drum Measurements Used to Characterize Powders for AM Applications." He shows the importance of imaging speed for capturing "real time" powder behavior. The MPPA Standards Committee and ASTM Committee B09 have conducted blind test programs to evaluate the ability of drum rheometers to discriminate between marginally different powders, as a prelude to developing standardized methods associated with the tests. present GKN Powder Metallurgy's current way of fatigue testing and provide step-by-step instructions for analyzing the fatigue data and converting it into Cracktronic plane bend fatigue testing unit. Data will be developed for inclusion AMPM2024 and the winning parts will be highlighted in the summer edition of reviewing and judging the best papers from the conference, and I look forward to publishing them in the fall issue of the journal.
