bluuebunny/crossref_metadata_2025 huggingface dataset:
In-situ And Ex-situ Heat Treatment Of LPBF PM HSS:
Solid Phase Transformation And Carbide Precipitation Behavior During Laser Powder Bed Fusion And Tempering Of High Speed Steel Parts
Authors: Bergmüller Simon , Kaserer Lukas , Leichtfried Gerhard
Published: November 2024

In this work, Boehler's powder metallurgical high-speed steel (PM HSS) S390 was processed via laser powder bed fusion (LPBF) at different substrate plate temperatures, and the resulting mechanical properties and microstructure were compared. High-alloyed tool steels processed via LPBF are prone to cracking because of their high content of carbon and carbide-forming alloying elements, such as the high-performance PM HSS S390 from Boehler, with 1.64 wt% C and W-Mo-V-Co-Cr (10–2-5–8-5 wt%). Cracks may be induced by thermal expansion and solid phase transformation combined with weak grain boundaries due to the presence of segregated primary carbides. Heating the substrate plate decreases thermal stresses and allows for in situ heat treatment, thus controlling solid phase transformation and carbide precipitation, and preventing cracking during cooling. The resulting microstructure, precipitates, and mechanical properties of the in situ heat-treated specimens (at 600°C and 800°C) and conventionally post heat-treated are presented.
Effect Of Hydrogen Heat Treatment Of Cold Spray Additively Manufactured Ti-6Al-4V
Authors: Dunstan Matthew , Butler Brady , Nault Isaac , Paramore James
Published: November 2024

Cold Spray Additive Manufacturing (CSAM) is a solid-state additive technology where metal powders are accelerated through a converging-diverging Laval type nozzle using a pressurized carrier gas. These powders are then sprayed onto a substrate in the shape of the desired component and subsequently removed. As only low temperatures (less than 1000 °C) are used during CSAM, the strength of the component relies completely on particle deformation and interlocking as very little diffusional processing takes place in order to create metallurgical bonds. Post-spray heat treatments are often necessary in order for components to achieve mechanical properties similar to other additive techniques. In this work, the heat treatment process known as Thermohydrogen Reduction of Microstructure (THRM), which was initially developed for laser based additive manufacturing, is applied to Ti-6Al-4V components produced via CSAM. Its effect on density, microstructure, and tensile properties are examined.
Laser Powder Bed Fusion Processing Of Complex Concentrated Alloys For Bio-implants
Authors: Mourgout Adrien , Hattal Amine , Gandolfi Juliette , Hocini Azziz , Mawussi Mawussi , Lebon Nicolas , PIRES Rémy , Perrière Loic , Dirras Guy
Published: November 2024

As the population in modern societies ages and the risks of bone diseases or bone accidents increase, there is a need for a new generation of materials with superior biocompatibility and good mechanical properties. This study combines two innovative metallurgical concepts to provide a material solution for the intended application. To this end, multicomponent and complex concentrated alloy (HEA|CCAs) based on TiNbZr-X (X = Mo, Ta) system is fabricated via additive manufacturing (AM), namely by Laser-Powder Bed Fusion (L-PBF) of gas-atomized pre-alloyed powder. After each stage of development by L-PBF through Taguchi's design of experiments, complete microstructure characterization and mechanical behavior of the resulting samples under different loading conditions are conducted. In addition, mechanical surface functionalization carried out by machining with metrological monitoring is carried out as a pre-step before a chemical functionalization for the suitability of materials developed for the intended application
Taylor-made Sintered Titanium Fiber Structures For Implant Applications
Authors: Andersen Olaf , Kostmann Cris , Weißgärber Thomas , Rüger Matthias , Pöhle Georg
Published: November 2024

A new approach to a biomimetic orthopaedic material designed for load bearing bone is presented. It is based on strategically layered, sintered titanium fibres with anisotropic mechanical properties adjustable in three dimensions (TiFi). The matrix material is cp titanium. Parallel and cross-ply topologies at two different porosities (75 and 85 %) were manufactured and mechanically tested. In vitro and in vivo biocompatibility testing was carried out. The tests performed on the new material demonstrated anisotropic mechanical properties similar to those of natural bone, excellent osteoconductivity and, thus, excellent properties for use as an orthopaedic implant material.
A Multiscale Study Of Boron And Carbon Behavior In The Necking And Fracture Zones Of The High Temperature Ni-based PM HIP Superalloy Under High Temperature Tensile Testing
Authors: Shulga Andrey
Published: November 2024

A multiscale study of boron, carbon behavior and the microstructure of PM HIP compact from high temperature Ni-based superalloy produced using PREP-powder under tensile testing at high temperature was performed. This study of boron and carbon behavior related to the microstructure of the necking and fracture zones, was carried out by direct methods track autoradiography on boron using the nuclear reaction 10B(n, a)7Li and activation autoradiography on carbon using the nuclear reaction 12C(d, n)13N, metallography, SEM, EDX, OIM methods. The formation of a mesocrack was revealed as the localization of plastic deformation before fracture, followed by a significant migration of boron and, to a lesser extent, carbon, precipitation of boride and carbide phases in the loop of maximum shear stresses for the mesocrack and in shear bands. It is important, that Intensive boron migration begins in the diffuse neck. The results revealed are explained by dynamic strain aging
Impact Of Printing Parameters On Green Density Homogeneity In Lithography-based Metal Manufacturing
Authors: Vogel Lucas , Zimmermann Martina , Burkhardt Carlo
Published: November 2024

Lithography-based metal manufacturing (LMM) is an emerging technology for the 3D production of metal parts with high dimensional accuracy and outstanding surface quality. To reliably reproduce these properties, a better understanding of parameter characteristics correlation is necessary. One of the most important characteristics of the printed part is the green density and its distribution within the building volume. This study investigates the printing parameters degree of powder filling of the feedstock, layer thickness, coating speed, coating mode and size of the material roll, with the help of a DoE. The green parts are getting characterised by dimensions, weight and density using the principle of Archimedes. Also, the strength of the green part is investigated. As the densification during sintering works as a magnifying glass for imperfections and differences in green density of the green parts, all samples get sintered and analysed on their density and shrinkage afterwards.
Feasibility Study Of Fabricating A Partly Amorphous Copper-rich Titanium Alloy Via In-situ Alloying In Laser Powder Bed Fusion
Authors: Goettgens Valerie , Leichtfried Gerhard , Mair Philipp , Mitsche Stefan
Published: November 2024

Bulk metallic glass composites (BMGCs) overcome the unfavorable lack of plastic deformation of completely amorphous alloys by adding ductile metallic shares. This is the first study that attempts to produce a partially amorphous alloy in an inexpensive and straightforward system of Ti-6Al-4V – 15 wt.% Cu using laser powder bed fusion (LPBF) with in-situ alloying. Local chemical inhomogeneities are desired, as they allow simultaneous solidification of different microstructures. In the produced alloy, fabricated with a single melting and a pulsed remelting strategy, partly X-ray amorphous material was found. The remelting strategy led to the increase of the X-ray amorphous phase and caused the number of grains smaller than 1 µm to increase from 7.8 % (single melting) to 14 %. This study shows the feasibility of producing a partly X-ray amorphous alloy in which the amount of X-ray amorphous shares can be controlled with process parameters.
High Strength Ti-Zr Alloys With Balanced Ductility Fabricated By Powder Metallurgy And Additive Manufacturing Routes
Authors: Kondoh Katsuyoshi , Issariyapat Ammarueda , Umeda Junko , Kariya Shota
Published: November 2024

The pre-mixed pure titanium (Ti) and zirconium hydride (ZrH2) powder was consolidated by PM process (sintering and hot extrusion) or AM process (selectively laser melting, SLM) to fabricate Ti-Zr alloys, which have excellent corrosion resistance and biocompatibility for human bodies. It was clarified that both materials showed uniform solid-solution of Zr atoms in a-Ti matrix and fine grains due to Zr solute drag, resulting in the significant improvement of tensile strength. In addition, the elongation more than 15% was also obtained in all samples. The quantitative analysis on Zr solution strengthening behavior of both materials was carried out using Labusch model.
Surface Machining Of Artificial Small-scale Flaws By Laser Ablation Routes In Hardmetals: Implementation And Potential Application For Assessment Of Damage Tolerance
Authors: Ortiz Laia , Liu Chao , Wang MS , Llanes Luis , Jiménez-Piqué Emilio
Published: November 2024

The precision offered for laser ablation has positioned it as an effective technique to generate micronotches used for evaluation of mechanical properties in structural materials. However, similar approach has not been attempted for hardmetals; thus, it becomes the main objective of this work. Dimple-like and elongated micronotches are introduced in a fine-grained 9%wtCo WC-base hardmetal using a laser machining platform consisting of a solid-state Nd:YLF, Q-switched laser set-up. In doing so, laser processing parameters are first optimized to attain micronotches with geometry and size similar to common critical flaws found in cemented carbide specimens. Success of the implemented approach is then validated through subsequent flexural testing and fractographic inspection of surface notched samples. The suitability of laser ablation for shaping artificial small-scale flaws opens a new route for introducing "controlled" defects, alike those intrinsic to processing or induced during service, key aspect for further understanding damage tolerance issues in cemented carbides.
MIM And Binder Based 3D-printing Approach Of High Strength Magnesium Alloy AZ41
Authors: Wolff Martin , Klahn Sara , Buresch Hendrik , Ebel Thomas , Willumeit-Römer Regine
Published: November 2024

Magnesium AZ-alloys are the work horse for many ultra-light-weight aerospace, automotive and consumer applications. Novel research introduces Mg-alloys also into binder based processing techniques, such as Metal Injection Moulding for economic near net shape mass production as well as 3D-printing for individual prototyping of complex shaped parts, even with hollow structures inside of a dense shell. This study handles two questions:How can the chosen AZ41-alloy exhibit maximum material properties and reproducibility using MIM? In addition, how can the 3D-printing processing be refined to come as close as possible to MIM? In order to answer these questions, several approaches in view of the used powder quality, particle distribution size as well as furnace and printing parameters were performed. Maximum ultimate-tensile-strength (UTS) of 226 ±7.1 MPa at 10.8 ± 2.1% elongation at fracture can be achieved using MIM. The 3D-printing approach could come close up to 89.5% of the MIM result.
Metal Binder-jetting Of Aluminum-based Alloys
Authors: Zanon Matteo , Müller Armin , Pelletiers Tom , Croteau Joe , Murphy Nicholas , Workman Joseph
Published: November 2024

Metal binder-jetting (MBJ) technology involves the additive build-up of "green parts" via localized deposition of liquid binder on a powder bed. Green parts are subsequently depowdered, debinded and sintered to near full density. A successful sintering becomes then the critical step for the development of both density and material properties. Aluminum-based alloys, while commonplace for laser-based technologies, have been hitherto neglected in the binder-based approach, due to their notorious oxidation sensitivity and possibly to their less visible presence in the traditional PM industry, compared to ferrous materials. By taking advantage of its multi-decade experience in mass production of PM aluminum grades, Kymera International is adapting several grades of free-sintering aluminum alloys, including those from the 6000- and other series, for use in binder jet additive manufacturing. Progress updates will be provided on the printing and sintering process and material properties after sintering and heat treatment.
Surface Processes On Dehydrogenation Of Titanium Hydride Powder Promoting Material Cleaning
Authors: Xu Huiyan , Bondarchuk Oleksandr , Savvakin Dmytro , Ivasishin Orest
Published: November 2024

Titanium hydride (TiH2) powder is used in powder metallurgy for manufacturing of titanium alloys and composites. In such approach, atomic hydrogen evacuated from hydrogenated powder during the vacuum sintering positively affects crystal structure of titanium, provides improved densification and cleaning of powder surface. We comparatively investigate impurities at the surface of titanium hydride and titanium powders, including oxygen compounds (titanium oxides, H2O). The X-ray photoelectron spectroscopy (XPS) was deployed to assess the forms of oxygen in both powders and their transformations during vacuum heating up to 600oC to elucidate the effect of TiH2 dehydrogenation process on the powder cleaning. The mass spectroscopy was used to follow the gases evolved during the TiH2 annealing; content of oxygen, nitrogen and hydrogen in powder before and after dehydrogenation was analyzed. Annealing protocol has been established to achieve better cleaning of the TiH2 powders and reduced impurity content in the sintered titanium-based products.
Measurement Of The Pore Diameter In Sintered Steels With Varying Porosity
Authors: Danninger Herbert , Hojati Milad , Tokatligil Deniz , Konegger Thomas , Gierl-Mayer Christian
Published: November 2024

Sintered steel parts contain porosity which at the usual density levels is predominantly interconnected and open. This affects secondary treatments such as carburizing or infiltration. The volume fraction of the open pores can be determined by He pycnometry, but also the pore diameter is relevant. In the present study, the pore diameter has been determined by Hg porosimetry on a plain carbon steel and a Cr-Mo prealloyed grade. Since the pore channels in PM steels are complex-shaped, different measures for the diameter were determined, the median, average and modal diameter. It showed that although these parameters differ for a given material, the more, the lower the density, in all cases there is a virtually linear correlation with the sintered density that holds for both sintered steel grades, indicating that at least for materials solid state sintered under defined conditions the density is the main factor determining the pore diameter.
The Master Sintering Curve And Its Application On A Dual Phase Steel Produced By Metal Binder Jetting
Authors: Schneider Markus , Wawoczny Dennis , Schaak Christopher , Koehnen Patrick , Schade Christopher T.
Published: November 2024

The Master Sintering Curve is a useful tool to compare different sintering profiles regarding their effect on the material shrinkage, especially for fine powders. This is reached by the stepwise contraction of sintering temperature and sintering time to a common sintering parameter and its sigmoidal correlation to the densification parameter as metric for the sintering response. The underlaying sintering kinetics are investigated in terms of its activation energy. Similar to Metal Injection Molding, Metal Binder Jetting is a two-stage Additive Manufacturing process which is characterized by its huge material shrinkage during the sintering to reach components’ final geometry and density. A new developed dual phase steel, which can be tailored for a variety of strength|ductility combinations, was characterized by dilatometry sintering trials and a subsequent generated Master Sintering Curve. Due to its printing texture the resulting material shrinkage exhibits an anisotropic behavior which must be considered.
What Happens To The Surface Composition Of Hardmetal, When It Undergoes Corrosion? An Electrochemical And Spectroscopic Investigation
Authors: De Gaudenzi Gian Pietro , Alleva Alessandro , Bagheri Sonia , Emanuele Elisa , Garabelli Mattia , Mele Claudio , Tavola Francesco , Tedeschi Sandra , Travella Augusto , Bozzini Benedetto
Published: November 2024

Functional performance of hardmetal grades is strongly controlled by the poorly understood ambient-dependent nature and evolution of the near-surface chemistry, either in operational ambient or in metal-recovery processes.We carried out a systematic study on Co-Ni alloy grades without|with Cr|Mo additions in neutral aqueous ambient. Electrochemical investigations, based on CV, PS and EIS measurements, SEM|EDX microscopy, spectroellipsometry and ICP analysis of electrolytes, lead to the rationalization of the irreversibilities of the hardmetal surface properties. We could identify two limiting classes of behaviour: (i) controlled by binder dissolution, and (ii) controlled by pseudopassive film formation, involving both binder and WC corrosion products. By control of the binder composition and of the ambient oxidizing power, one can stir the behaviour of the grade towards one of the two regimes, in order to engineer the surface response to optimize: (i) corrosion and (ii) tribocorrosion resistance, (iii) room-temperature, green recovery of metal from scrap.
Anomalous Particles (granules) In PREP-powders. A Multiscale Study Of The Structure Evolution Of The PM HIP Stainless Steels Under Hot Deformation And Heat Treatment
Authors: Shulga Andrey
Published: November 2024

The occurence of anomalous particles (granules) with significantly different content of interstitial microalloying elements carbon and boron is an important features of the homogeneity of the composition of rapidly quenched powders of stainless steels and Ni-based superalloys produced by the PREP method. A multi-scale experimental investigation of the evolution of the structure of the PM HIP stainless steels under hot deformation and heat treatment was performed. Direct nuclear methods of activation autoradiography on carbon, track autoradiography on boron, metallography, SEM, EDX, and OIM were used to reveal the evolution of the microstructure of the PM HIP stainless steels. A significant effect of hot deformation and heat treatment on the behavior of carbon and boron in PM HIP stainless steels has been revealed in comparison with their traditional counterparts. Essential lnfluence of the evolution of carbon and boron on the mechanical properties of PM HIP stainless steels was found
Understanding The Effect Of Process Parameters On Three-dimensional Pore Configurations And Mechanical Properties Of Laser Additive Manufactured Ti Using Synchrotron X-ray Computed Tomography And Homology
Authors: Shigeta Yuji , Aramaki Masatoshi , Kudo Kentaro , Shinagawa Kazunari , Nomura Naoyuki , Kondoh Katsuyoshi , Hoshino Masato , Uesugi Kentaro , Ozaki Yukiko
Published: November 2024

To establish a quantitative relationship between fabrication parameters, pore-configuration, and mechanical properties in porous materials, the pore configurations were visualized by X-ray computed tomography (CT) about pure Ti-AM specimens fabricated under different laser beam conditions. Radius and sphericity of all pores were obtained by image analysis. Furthermore, using the 0th persistent homology, the pore configurations were qualified by the pair of birth and death values, b and d for all pores: |b| means a pore radius and d correspond to a half distance between adjacent pores. The significant correlations were confirmed between tensile strength|elongation and the parameters: the maximum value of |b|, the ratio of the mean values of |b| and d (neck geometry), and the sphericity of the largest pore. These were proposed as useful structural parameters representing 3D pore-structure in porous materials.
A Comparative Study On Different Joining Techniques For PM-HIP Evacuation Tubes
Authors: Mirz Markus , Franke-Jurisch Marie , Herzog Simone , Kaletsch Anke , Broeckmann Christoph
Published: November 2024

The main purpose of evacuation tubes in powder metallurgically-based (PM) Hot Isostatic Pressing (HIP) lies in the evacuation and outgassing of the capsule. Conventional HIP capsules are made of sheet-metal which exhibits good weldability and therefore, it is easy to join the evacuation tube. With the emerging technologies of Additive Manufacturing (AM) it is now possible to design more complex capsules for HIP. Additionally, wear-resistant materials can be utilized. Yet, these materials are known to be difficult to weld. This study compares three different approaches to bond an AISI 304 evacuation tube to a HIP capsule made by Electron Beam Melting (EBM) from high carbon tool steel AISI A11. Capsules were bonded by TIG welding as well as brazing with conventional and a customized filler material based on thermodynamic calculations. Subsequent consolidation by HIP, microstructural analysis and argon-measurements revealed the feasibility and limits of all three approaches for gas-tight bonds.
Improved Thermal Conductivity Of PBF-LB AlSi10Mg Aluminium Structure Through Application Of Post Build Heat Treatments
Authors: Liu Yijun , Cruchley Nick , Larkin Owen , Santos Pedro , Carpenter Charley
Published: November 2024

AlSi10Mg is one of the most widely investigated and deployed aluminium alloys in the world of laser powder bed fusion (PBF-LB). It is now well established for the production of complex and lightweight components which require high strength and specific thermal conductivity. Notable applications include electric motor casings and heat exchangers, which will be increasingly important as the transport sector moves towards electrification. Despite extensive previous research on PBF-LB AlSi10Mg, work on improving the thermal conductivity is lacking – it is this knowledge gap which this paper attempts to address. The work presented demonstrates significant improvement in the thermal conductivity of PBF-LB processed AlSi10Mg through a series of heat treatments. A combined HIP-quenching with high-pressure aging process produced the highest increase in thermal conductivity in the temperature range of 25°C to 250°C. This route also resulted in improved tensile properties compared to traditional HIP and T6 cycle heat
Synthesis And Characterization Of Nanostructured Hydroxyapatite With The Use Of Porogenic Agent For Applications As Catalyst In The Production Of Biofuels
Authors: Brant de Campos Jose , Dias Senra Jaqueline , Quizunda Adilson Claudio , Sampaio Aguilar Marilza , de Souza Baêta Júnior Eustáquio , Loureiro Stavale Junior Fernando
Published: November 2024

Hydroxyapatite (HAP) has been one of the most researched ceramic materials for application in bone implants and as a catalyst system. In this context, HAP has been used as a material system for ethanol conversion, like for n-butanol and for Butadiene. In this context, the present work aims to carry out a conversion reaction using the HAP obtained from hen skin with sucrose as a porogenic agent and ethanol as the catalytic system. The conversion reactions will take place at a temperature of 300 °C at rest and it will be conducted in a 30 mL steel alloy autoclave. The autoclave will be sealed and placed in a preheated oven at 240 °C, with different reaction times, weight and temperature, as experimental variables. The reaction products will be evaluated by chromatography, BET, SEM and XRD techniques and it is expected that its behavior would reach a high reaction yield.
Intelligent Sintering Atmosphere Optimisation And Cloud-based Advisor Services
Authors: Kus Paulina , Plicht Guido , He Liang , Lee Thomas , Meining Jannis , Garcia Eduardo , Kroschwald Lisa , Husmann Simon , Fitsall Geoff
Published: November 2024

Continuous sintering of metal parts under a Nitrogen|Hydrogen atmosphere is one of the most complicated heat treatment processes. Although the industry has established standard processing methods, the technical challenges still remain to minimize part defects, rework, and the excessive use of energy.Sustainability is one of our social responsibilities, requiring continuous improvement to engineer technologies and processes to reduce waste and emissions, and minimize our use of resources.Air Products, Bleistahl and K2 have partnered to develop a cloud-based optimization system dedicated to sintering. This Industry 4.0 tool enables recording and analysis of the process parameters, linked to operational results, facilitating process optimization and product quality improvement. Integrated with thermodynamic calculations, field experience, and documentation features, the tool provides process engineers with extended capabilities to manage the production, and support process troubleshooting, audits, and CQI-9 compliance.
3D Printing Of H13 Tool Steel Filaments : Influence Of Debinding|sintering Atmosphere On The Microstructure And The Mechanical Properties Of Sintered Parts
Authors: Lacorne Jordan , Maire Eric , Etiemble Aurélien , Boulnat Xavier , Faye Romain , Simon Sandra
Published: November 2024

Additive Manufacturing is a growing sector in industrial production. Fused Filament Fabrication (FFF) technology is developing by using new materials such as filaments incorporating metal powder (40 to 60%vol) and thermoplastic binders. After 3D printing, FFF needs two more steps: debinding, where the binder is removed, and sintering, where the porous part is densified. The nature of the protective atmosphere is critical because it influences the binder removal and also the sintering|oxidation behavior of the metal powders. This work aims to study the influence of atmosphere (gas type and flow rate) during debinding and sintering on the properties of the final parts in work tool steel (AISI H13). The link between atmosphere and carbon|oxygen uptakes, porosity, microstructure, and mechanical properties will be described.
Additive Manufacturing Of Complex NiTi Structures Using Fused Filament Fabrication (FFF) And Subsequent CNC Green Machining
Authors: Riecker Sebastian , Teuber Robert , Abel Johannes , Mannschatz Anne , Müller Bernhard
Published: November 2024

Pseudoelastic behavior with elastic strains of up to 8 % and the shape memory effect are well-known features of nickel-titanium alloys (Nitinol). These properties are highly interesting for the fabrication of e.g. functional auxetic and programmable structures as well as for solid state joints and compliant mechanisms. To extend the current range of available geometries and to enable near-term fabrication of customized complex devices, sinter-based additive manufacturing (AM) of NiTi components via Fused Filament Fabrication (FFF) has been investigated. For this purpose, a highly filled thermoplastic filament (63 vol.-% powder) has been developed which could be printed to complex geometries using standard FFF printers. The AM post-processing steps of debinding and sintering were aiming for extraction of O, C and N to achieve the desired properties. Green state machining experiments resulted in high part quality and low surface roughness of Ra less than 5 µm.
Development And Characterization Of W-based Feedstock For Extrusion-based Additive Manufacturing
Authors: Etiemble Aurelien , Commeau Thierry , Nouveau Aurélie , Simon Sandra , Rigollet Claire
Published: November 2024

The applicability and expansion of the promising opportunities offered by extrusion-based technologies for the additive manufacture of metal parts (FFF, FDM or PIM-like) depends on the development of new feedstock for specialty powders. In this context, W-based feedstock was developed and characterized in this study. For these indirect processes, the feedstock is firstly extruded to form a wire and is then deposited to shape the part. Debinding and sintering operations are finally required to obtain the finished metal part. The feedstock formulation was optimized to allow and then to enhance the processability at all these steps. The printability of W-based feedstocks is demonstrated and a critical powder content, required to guarantee the efficient debinding and sintering, is established. Microstructure and mechanical properties (hardness) of sintered parts were characterized and compared to conventionally manufactured parts.
Data-Driven Methodology To Identify Design Parameters For The Calculation Of Reliable S-N Curves For PM Components
Authors: Reissner Felix-Christian , Haberlick Etienne , Baumgartner Jörg , Burkamp Karl
Published: November 2024

This paper describes a data-driven methodology to derive reliable S-N curves for PM components that take the hardness, the highly stressed volume, the stress ratio and the density into account. The methodology aims for a fatigue assessment approach applicable for all PM steels. For this, a large database with approximately 800 S-N curves, 20.000 S-N experiments and a broad spectrum of different geometries, materials, loading conditions, sinter conditions etc. is set up. The methodology is based mainly of known analytical functions, such as the Bal’shin equation and the Haigh diagram. The parameters for the fatigue assessment are obtained by optimization of the used analytical functions. As a result, the model leads to a highly reliable fatigue assessment of PM components.
Roller Hearth Sintering Furnace (RHF): Operating Economics
Authors: N Gopinath , Kruzhanov Vladislav , Arnhold Volker
Published: November 2024

Product transport in a RHF (parts on graphite trays on driven rollers) differs from mesh belt furnaces (MBF) where parts are placed directly on the belt or on trays on the belt.Trays in the RHF eliminate the mesh belt and allow the use of entry & exit lock chamber doors which reduces gas consumption compared to two end open mesh belt furnaces.This article examines the consequent cost of processing in a RHF compared to a similar capacity MBF, both operating at 1130°C, the high temperature sintering capability of the RHF not considered.Also examined are effects of higher cooling rates on the mechanical properties of two PM parts with lower alloy content that are sinter hardened in a RHF where cooling fan speeds are higher than in MBFs due to doors enclosing the cooling chamber and in addition, increased cooling chamber pressure for increased heat extraction.
Investigating The Effect Of Compaction Parameters On The Dimensional Changes On Sintering
Authors: Utku Uçak Onur , Zago Marco , Voglhuber Juergen , Bolitschek Johanna , Cristofolini Ilaria
Published: November 2024

Anisotropic dimensional change on sintering has been studied in depth in previous work, as affected by powder mix, geometry, sintering conditions etc. Previous results also revealed anisotropic dimensional changes in the compaction plane, to be necessarily considered when designing precise and accurate parts. Anisotropy in the compaction plane is expected to be markedly affected by inhomogeneities in green density distribution, in turn related to compaction strategy. Aiming at investigating in depth the influence of the compaction strategy, compaction speed, hold down force, and hold down time were selected as parameters. Full factorial testing was performed, three levels for each parameter, and three different materials were considered. Dimensional changes were measured, and the effect of the selected parameters was analyzed, also referring to the different sintering mechanisms occurring in the different materials. As a result, relationships describing the effect of the compaction parameters on the dimensional changes are proposed.
Ordered Diamond Arrangement In A Sinter-Based AM Process
Authors: Studnitzky Thomas , Weißgärber Thomas , Strauss Alexander , Jank Michael , Büttner Dirk
Published: November 2024

Diamond based grinding or cutting tools usually consist of randomly packed diamond particles inside a metal matrix. Nevertheless it is known that an ordered arrangement of diamonds shows much better performance with defined wear of the tool, which typically leads to a longer service life time. Several approaches and patents were already published on this topic, but due to the high complexity of the manufacturing process the market penetration is still low. Fraunhofer IFAM and DiaBü have developed a modified 3D screen printing process which allows the manufacturing of cutting beads with ordered diamond structure in a mass production process. With 3D screen printing, a user defined 3D arrangement of cavities can be built, into which the diamonds are incorporated. After closing of the cavities, the beads are debound and sintered. In the present work also results of cutting tests of beads with an ordered diamond structure will be presented.
Brake Discs Made Of Aluminum-Matrix-Composites
Authors: Trapp Johannes , Schubert Thomas , Storz Andreas , Mitrica Dumitru , Anasiei Ioana , Weißgärber Thomas
Published: November 2024

Aluminum-based metal-matrix-composites (AMCs) show attractive properties to meet the growing demand for lightweight construction for example in the automotive and aerospace industries. Limiting factors are difficulties in processing and machining as well as comparably low operating temperatures. The first issue is addressed using spark plasma sintering (SPS) to produce fully dense net-shape compacts. Therefore, the electrical properties of the powders must be understood and adjusted. To increase operation temperature, alloys with thermally more stable Al3Fe dispersoids, certain intermetallic phases, or complex constitutional alloys have been investigated. The latter are developed with the help of a systematic selection process to calculate the thermodynamic and kinetic criteria to predict the phases formed. Those AMCs show melting temperatures above 1000 °C while keeping the density below 4,5 g|cm³. Aiming for compressive strength > 800 MPa and elongation to fraction >1 % makes the materials suitable e.g. for front wheel brake disc applications.
Repairing D2 Tool Steel Parts By Directed Energy Deposition Using A Hot Work Tool Steel Or A Metal Matrix Composite
Authors: Vincic Josip , Manfredi Diego , Lombardi Mariangela , Aversa Alberta
Published: November 2024

The D2 tool steel is a cold work tool steel with high hardness and high wear resistance, but not easy to be welded due to its high carbon content. On the other hand, as a result of the growing need for faster production, industries are facing higher tool wear than expected. The high costs of replacing tools has prompted thinking about repairing them. The aim of this study was to evaluate the possibility to repair D2 tool steel parts with a hot work tool steel or with a metal matrix composite using directed energy deposition (DED). The optimal parameters were found by depositing and analysing first single tracks, then single layers and ultimately multi-layers. The samples were analysed from a microstructural point of view, by optical and electron microscopy, and from a mechanical point of view, by hardness measurements. This work demonstrates the potential of DED for repairing industrial tools.
First Insights In The Development Of TRIP|TWIP Ti Alloys Designed By And For Additive Manufacturing
Authors: Coffigniez Marion , Duchaussoy Amandine , Choisez Laurine , Marteleur Matthieu , Papillon Justine , Maire Eric , Jacques Pascal
Published: November 2024

ß-metastable Ti alloys exhibit a very large work hardening rate together with an outstanding resistance to damage nucleation, bringing a very high ductility. Such a behavior could enable to counteract the decrease of mechanical properties caused by solidification cracking|hot tearing, balling or porosity formation during laser powder bed fusion. The binary Ti-12 wt.% Mo grade was chosen as a case study, using powder mixture as a first approach. As-printed microstructures highlight the formation of structures related to the solidification scheme, as well as specific Mo solute partitioning depending on the printing parameters. Such a specific microstructure brings a large increase of the tensile strength compare to the cast reference. Furthermore, when the chemical homogenisation obtained is large enough to reach 95 % of ß-metastable microstructure, ductility comparable to the cast reference is reached after a simple flash heat treatment, as well as an outstanding low sensitivity to defects.
Development Of X40CrMoV5-1 (H13) On Binder Jetting Technologies
Authors: Reynaud Christophe , Baulin Oriane , Saby Quentin , Boulnat Xavier , Reinwalt Bastien
Published: November 2024

Cetim has launched further material project development on binder technologies. This work deals with the development of the tool steel X40CrMoV5-1 or H13 on two Metal Binder Jetting technologies, namely DM P2500 (Digital Metal) and Lab P-1 (Desktop Metal). The whole MBJ H13 has been developed by adjusting the 17-4PH powder printing parameters and by developing a specific sintering recipe by using a vacuum metallic furnace under controlled atmosphere (one step debinding sintering). The presentation will be focused on sintering development. Controlling the final carbon content and achieving high density level without excessive component distortion by using SLPS process are the main challenges to overcome. The microstructure and the mechanical properties are compared. For both technologies, as sintered mechanical properties are consistent with data coming from MIM H13 materials and wrought materials.
Microstructure And Mechanical Properties Of Heat Treated FSLA Steel Produced By The Binder Jet Process
Authors: Schade Chris , Junghetu Corina , Horvay Kerri , Murphy Thomas , Schade Chris
Published: November 2024

An alloy, called FSLA (free-sintering low-alloy), was designed and implemented for use with binder jet printing. This work focuses on various heat treatments that can be utilized with the alloy to produce a range of properties for various applications. The microstructure of the alloy can be varied post-sintering, by heat treatment, to give a wide range of mechanical properties that are suitable for automotive components. Balancing the carbides in the structure along with the amounts of ferrite and martensite|bainite give a range of ultimate tensile strengths from approximatelt 490 to 1000 MPa. Unlike other low alloy steels, the material has been designed to have a high degree of sinterability which allows densities of the order of 98% to be reached while sintering at temperatures typically used in metal injection molding (1380 degrees Celcius).
Microstructure And Properties Of Composites Manufactured By High-Energy Ball Milling And Spark Plasma Sintering From WC|Ti Powder Mixtures
Authors: Wisniewski Jakub , Marczewski Mateusz , Adamek Grzegorz , Garbiec Dariusz
Published: November 2024

The constant development of technology involves the need to enhance materials, including those used for machining, for instance for cutting inserts. The most common material from this group is WC-Co, which is characterized by high hardness and fracture toughness. Nevertheless, cobalt has a high and unstable price, its resources are limited and it is considered a toxic element. All those disadvantages have led to many studies focused on replacing cobalt with other binders. One of the most promising solutions may be titanium, with a similar melting point, much lower price and confirmed biocompatibility. The desired phase composition and good homogeneity of WC-Ti composites may be induced by milling of the initial powders. The mechanical properties and microstructure are also strongly connected with the sintering process. FAST|SPS as advanced technology allows the manufacture of materials with finely tailored properties. The microstructure and mechanical properties of WC-Ti composites were investigated.
Investigation Of The Potentials And Current Limitations Of Multi-material Manufacturing Of Metals By Powder Bed Fusion Based On A Copper And Steel Material Combination
Authors: Schroeder Timo , Kindermann Philipp , Schmitt Matthias , Schlick Georg , Horn Max
Published: November 2024

Multi-material manufacturing of metals by powder bed fusion (MM PBF-LB|M) combines the ability of building complex structures with the capability to create an arbitrary material distribution in one process. The possibility of arbitrary material distribution in one part enables future applications. However, one challenge in MM PBF-LB|M is to ensure powder purity during the build process, which is influenced by the technology maturity of the MM PBF-LB|M system. Impurities in the manufactured part can lead to the deterioration of material properties and therefore must be avoided. This paper investigates the current state of the MM PBF-LB|M systems technology and the achievable material purity. The resulting material properties depend on the powder purity and reprocessing ability for copper and steel specimens. As critical sub-systems, the application mechanism and the powder extraction module required for the holohedral application mechanism are identified. Finally, improvement measures for the MM PBF-LB|M process are derived.
Production And Processing Of Tungsten-Based Powders In Thermal Plasma Systems
Authors: Samokhin Andrey , Alexeev Nikolay , Sinaisky Michael , Fadeev Andrey , Dorofeev Alexey
Published: November 2024

The report presents the results of R&D of plasma-chemical production of W nanopowders, W-Cu, W-C, W-Ni-Fe powder nanocomposites, WC tungsten monocarbide, as well as spherical micropowders of these compounds for their use in modern 3D printing technologies. Plasma-chemical synthesis of tungsten nanopowder is based on the reduction of tungsten oxide compounds powders in a stream of hydrogen-containing low-temperature thermal plasma generated in an electric arc plasma torch. The synthesis of W-Cu and W-Ni-Fe nanocomposites is carried out using the reduction of a mixture of the metal oxides, Using the synthesized tungsten-based nanocomposites powders, spherical composite micropowders with a submicron structure can be manufactured by granulation of nanopowders and subsequent spheroidization of granules by melting in a low-temperature thermal plasma. The results of the development of DC arc plasma systems for the synthesis of nanopowders and micropowders spheroidization are presented.
Laser Powder Bed Fusion Of A Novel CoCuFeMnNiTi High Entropy Alloy: Processing And Characterization
Authors: Fiocchi Jacopo , Biffi Carlo Alberto , Elnemr Menatalla , Tuissi Ausonio , Casati Riccardo
Published: November 2024

In the present work the possibility of processing a CoCuFeMnNiTi high entropy alloy by laser powder bed fusion (LPBF) is explored. Such composition was specifically tailored with the aim of allowing the precipitation of strengthening second phases during post-processing ageing treatment. A suitable processing window was found by varying processing parameters and the obtained material was characterized under different perspectives. The as-built material consists of a single face centred cubic phase, whose ageing behaviour appears to be influenced by the experienced rapid solidification conditions. The correlation between the resulting microstructures and the corresponding mechanical properties was studied by means of hardness tests, calorimetric analyses and scanning electron microscopy. Finally, the mechanical response of the alloy was analysed, so as to investigate the activation of various plastic deformation mechanisms under different combinations of deformation extent and heat treatment condition.
Characterization Of Soft Magnetic Composites With Ceramic Coating Produced By Hot Press
Authors: Sota-Munoz Angel , Burgos Nerea , Zhukova Valentina , Ipatov Mihail , Martin Jose Manuel , Gonzalez Julian
Published: November 2024

Iron silicon gas atomized powder was coated with iron phosphate, epoxy resin and a mix of both to make soft magnetic composites (SMC). Iron phosphate composites were consolidated by cold pressing at 800 MPa or hot pressing at 825 ºC and 50 MPa. Composites made from epoxy resin or a mix of epoxy|phosphate were consolidated by cold pressing at 800 MPa. The microstructural characterization of the new cores was carried out by high resolution scanning electron microscopy. Differential scanning calorimetry showed that a degradation of the phosphate coating occurs at temperatures above ~880 ºC due to a reaction with silicon, limiting the maximum temperature for hot pressing. The best combination of properties was obtained for the hot-pressed iron phosphate composite, reaching high density (6.59 g|cm3), high electrical resistivity (~105 µO·cm), high saturation magnetization (1.75 T) and a low coercive field (~315 A|m).
Metal Diamond Composites -- A Way For Industrial Production And Material Integration Into Power Module
Authors: Hutsch Thomas , Rittner Martin , Zetterer Thomas , Weißgärber Thomas
Published: November 2024

The ongoing development of power modules for electronics in the field of electromobility, charging infrastructure and photovoltaic based on SiC chips come up with a strong demand on tailored thermal management materials with high thermal conductivity, tailored coefficient of thermal expansion, soldering workability and a way for industrial production. In this paper the developed routine for the industrial production of metal diamond composites inspired by the wafer technology for semiconductors will be presented using the example of copper diamond composite. For the material integration into power modules by soldering the composite needs a cover with pure copper on both sides. The cross section, thermal conductivity and coefficient of thermal expansion will be displayed for the single composite, the covered composite and after integration into active metal braze (AMB) substrate. Aspects for the further integration into a power module design will be discussed and shown for one example.
Morphological Evaluation Of Metal Powder To Predict Performance In Powder Bed AM
Authors: Rahimi Ehsan , Hunt Adam , Hao Xinjiang
Published: November 2024

Physical properties of metal powder such as flowability, spreadability and packing density are critical to the performance of powder bed additive manufacturing (AM) processes. This research offers a versatile approach to evaluating metal powders for the laser powder bed fusion (L-PBF) process by correlating morphological classifications against the physical properties of the powder and processability during the powder bed re-coating process. Static image analysis was used to measure and classify the powders by a predefined set of rules based on shape descriptors of the powders. These classification groups quantify the powders in terms of highly circular, circular, minor satellited, major satellited, elongated, agglomerated and undersized particles. These classifications were compared against data from a rotating drum test and an automated dynamic tap density analyser. A new weighted index has been proposed to represent the combined influence of size and morphological classifications on the flowability and processability of powders for L-PBF.
Binder Jetting Additive Manufacturing Of M2 Tool Steel: Processability And Properties
Authors: Azurmendi Naiara , Lores Asier , Agote Iñigo , Laskurain Andoni
Published: November 2024

Binder Jetting Additive Manufacturing technology permits the processing of a wide range of different metallic alloys which cannot be easily manufactured by other AM means, as they may present undesired microstructures or anisotropic functional properties. For this reason, it has been found that BJ can be a suitable AM technology for processing tool steels and obtaining high quality parts with isotropic properties. In the present work, commercial M2 tool steel powder was studied and processed by Binder Jetting under different processing conditions. After some optimization work, near full density was achieved (>99%), together with MIM-like microstructure and hardness (51 HRC). Therefore, this study demonstrates that good quality M2 parts can be obtained by means of BJ, opening new design and manufacturing possibilities for more complex and advanced tooling applications.