bluuebunny/crossref_metadata_2025 huggingface dataset:
Innovative Full-scale 3D CFD Simulation Of A HIP Furnace In Operation
Authors: Yan Zhenghua , Eklund Anders , Liu Yan
Published: November 2024

Hot isostatic pressing (HIP) is a crucial process to densify and enhance the material properties of components in aerospace, energy, medical and additive manufacturing. In recent years people start to focus on understanding the shrinkage and deviation of parts in the HIP process by calculating the temperature-pressure behaviour on parts during heating, steady-state and cooling.This work shows 3D computational fluid dynamics (CFD) as a powerful tool to obtain an increased and complete understanding of the details in thermal gradients and gas flow inside the HIP furnace. An innovative full-scale 3D CFD simulation method of a HIP furnace in operation will be presented. This innovative method allows detailed full-scale 3D calculation of all the important processes including the gas flowing, pressing, thermal radiation and conjugate heat transfer in solids and fluids so that the HIP process can be best simulated in reality without unnecessary error-bringing simplifications.
Influence Of Rheological Properties Of Dry Metal Powders Formulated For Hot Isostatic Pressing
Authors: Tuzemen Gundogan Cansinem , Gulcan Yesim Nur , Pehlivanogullari Baris , Yilmaz Rifat , Orhangul Akin , Akbulut Guray
Published: November 2024

Nickel base superalloys are the most promising and preferred metal alloys over decades for high temperature applications. Hot Isostatic Pressing (HIP) is one of the most common and effective powder metallurgy technique used for consolidate Ni-Based superalloy. HIP has several advantages such as high densification rate, able to consolidate materials, which have a high melting point and also produce near net shape parts. In this study, particle size distribution (PSD) and rheological properties of powders were selected for investigation. Rheological properties of powders which have various|different particle size and distribution were tested. Compatibility, densification behaviour and mechanical properties of consolidated samples were also investigated. The result can be summerized classes having Gaussian PSD with Hausner Ratio below 1.20 show similar packing and flow properties after classification.
Effect Of Crack Initiation Size And Residual Stress On Bending Fatigue Strength Of Sintered Pre-Alloyed Steel
Authors: Shirafuji Tsukasa , Taniguchi Yuji
Published: November 2024

The fatigue strength of sintered steel is normally lower than that of conventional low-alloyed steel, such as JIS SCr420 and JIS SCM415 and so on,The fatigue strength of sintered steel is normally lower than that of conventional low-alloyed steel, such as JIS SCr420 and JIS SCM415 and so on, due to the porosities inside the material. However, it has been reported that tooth bending fatigue strength of sintered gears manufactured from 46F4H (0.5Ni-1.0Mo Pre-alloyed Steel Powder) is improved by surface-rolling and that the fatigue strength is equal to or higher than that of the gear manufactured from the wrought steel. In this study, we found that the reason why surface-rolled sintered steel gears have high fatigue strength is caused by both a decrease in size of the initiation fatigue crack due to eliminate the porosities in the vicinity of surface of the gear, and high compressive residual stress.
Mechanical And Micro-structural Properties Of Mechanically Alloyed Mgal Sintered Cith Electric Field Technique
Authors: Tekin Tugce , Aydin Sohret Melda , Yahsi Yasemin , Ferik Semih R. , Ipek Rasim
Published: November 2024

In this study, high-strength aluminium-magnesium alloys were prepared by AC- electric field technique (FAST) using powder metallurgy. Effects of sintering temperature on the Al-Mg microstructure and mechanical properties were investigated. Results from microstructural observations indicate that the density decreases with the increase in the sintering temperature; also, the maximum compressive strength and hardness values increased. The sample of Mg22Al at 300 ∘C under a pressure of 30 MPa reached nearly full density (≈0.99 ρt), it has 510,4 MPa compression strength and 167,90 HV30 hardness value as the highest value among the samples. Using X-ray diffraction, intermetallic compounds such as Al3Mg2, Al12Mg17, MgO, MgAl, and Al2O3 were detected. These results can be attributed to the existence of Al. Al also plays a role as bonding phase-materials between Mg powders.
On Metal Powder Tribocharging, Humidity Adsorption And Magnetization
Authors: Marchetti Lorenzo , Mellin Pelle , Neveu Aurelien , Hulme Christopher
Published: November 2024

In this work, three characterization techniques were applied to a set of alloys in fine powder form (TiAl6V4, AlSi10Mg, AlSi7, 316L, ferritic stainless steel, martensitic stainless steel and WC-Co-mixes). We sought deeper understanding of response to humidity and flowability as a result of the powder alloy. Slight tribo-charging (induced and measured using a GranuCharge setup) against metal surfaces was found to occur for all alloys. Although the accumulated charge was small and dissipated quickly. Greater charging occurs if the environment is humid, and if the powder slides against plastic surfaces. Dynamic Vapor Sorption (DVS) was employed to understand the adsorption capacity of powders. It showed that WC-Co-mixes adsorbed much more humidity than the other materials. Some alloys retained some of the adsorbed mass, when humidity returned to normal conditions. RPA was tested on powders during exposure to 20-98% RH, which above 80% RH caused a dramatic decline in flowability.
Spreadability Performance Of Four Different AlSi10Mg L-PBF Powders
Authors: Mellin Pelle , Strandh Emil , Heikkilä Irma , Uhlirsch Markus , Blackwell Cameron , Meisnar Martina , Pambaguian Laurent
Published: November 2024

Herein we describe testing of four AlSi10Mg L-PBF powders, sourced from different suppliers, using an off-the-shelf AB4120 automatic film applicator from TQC Sheen. With a 3560|2 gap applicator from Elcometer we produced 150 µm thick layer strips, at 150 mm|s. 3D-scanning confirmed near-target thicknesses, and near-anticipated layer volume.The powders were ranked based on their layer density. The same ranking was obtained for apparent density and tap density. In turn, these densities correlated with the overall sphericity of the powders. 3D-scanning (using a GOM ATOS Core 200) can highlight layer defects such as waves, skips and streaks. These defects were found in greater numbers for the worst powder that contained more oversize and irregularly shaped particles.
Process Development Of Grade A11 High Carbon Tool Steel For Metal Binder Jetting
Authors: Barthel Bastian , Mirz Markus , Petzoldt Frank
Published: November 2024

Grade A11 (X245VCrMo8-5-1) tool steel is one of the most commonly used tool steels for cold work applications as its high carbide content makes it highly wear resistant. However, its total carbon content of 2.5 % also leads to challenges in shaping by additive manufacturing, especially for LPBF. With its homogeneous temperature distribution during the consolidating sintering step, metal binder jetting (MBJ) capable to process a wide range of materials, including difficult-to-weld materials.This research focuses on the process development for grade A11 tool steel using MBJ. After the development of suitable printing parameters considering layer thickness and recoat speed, the sintering behaviour is investigated in detail. Initial sintering parameters are determined by thermoanalytical measurements. Subsequently, the impact of different sintering temperatures and atmospheres on the microstructural evolution are presented. Finally, it is shown that complex applications can be manufactured true to size and fully dense with the parameters determined.
Manufacturing Of A Porous Metallic Panel By Spark Plasma Sintering For Hybrid Laminar Flow Control Application
Authors: Egreteau Baptiste , Davoine Cécile , Vermeersch Olivier , Thomas Marc , Méry Fabien
Published: November 2024

Hybrid laminar flow control uses wall suction through a porous panel to delay the so-called laminar-turbulent transition, thus reducing the aircraft fuel consumption. This technology requires a skin panel with very good transverse permeability and an excellent surface finish. Currently, laser micro-perforated titanium panels are used, but the minimum diameter of the holes is limited, hindering a better suction distribution. Moreover, these titanium panels are difficult and expensive to produce. This is the reason why spark plasma sintering is used here to produce a porous material through partial densification of Ti64 powder. The samples have been characterised through tomography, and permeability tests to correlate the material’s structure with its suction performances. Indeed, as spark plasma sintering is a field assisted manufacturing process, the material might have enhanced suction performance in the application direction of the electric field.
Properties Of PM Steel Alloyed Through The Masteralloy Route - A Comparison To Conventional PM Grades
Authors: Geroldinger Stefan , de Oro Calderon Raquel , Gierl-Mayer Christian , Danninger Herbert
Published: November 2024

The PM steel industry is heading for radical changes, especially concerning the mobility sector. This is accompanied by challenges: New markets for the PM industry should be acquired, and with that, improved materials are mandatory for the future. On the other hand, well established alloying elements such as Cu and Ni undergo critical price fluctuations and are increasingly considered as strategic materials. Alloying elements well known in ingot metallurgy, such as Cr, Mn and Si, are attractive in their effects but limited in PM applications due to their high O affinity. The masteralloy (MA) route using MAs containing Fe, C, Si, Mn and | or Cr is a promising technique making these alloying elements available for the PM route. In this study, PM steels alloyed with MA are compared to commercially available pre-alloyed and diffusion alloyed powders in terms of microstructure, hardness, young’s modulus, flexural strength and impact energy.
Analysis Of Powder Characteristics And Powder-Binder-Interaction For Process Parameter Prediction In Metal Binder Jetting
Authors: Reineke Lea , Barthel Bastian , Hein Sebastian Boris
Published: November 2024

Metal Binder Jetting (MBJ) has an increasing attention in additive manufacturing because of its serial production potential. The aim of this work is to achieve the most suitable parameterization of the MBJ printing processes for specific powder-binder combinations, based on the powder characteristics and the powder-binder interaction. Depending on wetting properties and acting capillary forces, some MBJ powders need more or less binder to generate parts with optimal properties. The use of too high binder saturations generally leads to density loss due to binder application, as well as increased carbon content of the final sintered part or even loss of geometrical features. Too low saturations result in low green strength as well as low part accuracy. The economic background of the development of pre-printing tests is a reduction in the number of iteration stages in material-specific process development, which saves costs, effort as well as material resources and printing capacity.
Energy Efficiency Of Press Drives - A Closer Look
Authors: Wehrli Alex
Published: November 2024

Energy cost and overall equipment efficiency have triggered the development of large electric powder compacting presses.Additionally, several OEMs have announced the implementation of stronger regulations in their supply chain with the aim to reduce the grey energy.With the increased complexity and precision of PM parts, hydraulic CNC presses have replaced the mechanical presses. By implementing high|low-pressure systems, fast movement actuators and intelligent pump technology, the energy efficiency was increased, but there remains a very high energy demand compared to the actual net energy required for compacting a part.In this study the energy consumption of hydraulic and electric drive systems for the upper ram and the die of a compacting press is calculated and compared with the actual net energy demand of a compaction part.It will be shown why and by what amount the electric drive outperforms the hydraulic drive when it comes to energy efficiency.
3D CFD Modelling Of Sintering Of Metal Binder Jetting Products
Authors: Liu Yan , Hosseini Seyed B. , Kimblad Hans , Persson Mats , Yan Zhenghua
Published: November 2024

Binder jetting process is a prominent 3D printing technology due to its cost-effectiveness and capability to scale up the production in terms of batch sizes. However, the green parts need several post-processes including curing, debinding and sintering to improve the parts' density and mechanical strength. These post-processes bring many challenges affecting the final part size and dimensional accuracy. To get the best result and desired material properties, precise temperature and atmosphere control are vital during each individual post-processes. This work shows 3D computational fluid dynamics (CFD) as a powerful tool to obtain such an objective. A full-scale 3D CFD simulation method of a sintering furnace in operation will be presented. This method allows 3D calculation of all the important processes including thermal gradients, gas flowing, thermal radiation, convection and conjugate heat transfer in solids and fluids so that sintering processes of metal binder jetting products can be well simulated.
Friction, Material Transfer And Wear Phenomena In Sliding Contacts Between Cemented Carbide And Aluminium During Metal Forming
Authors: Cinca Núria , Gordon Sandra , Llanes Luis Miguel , Olson Mikael
Published: November 2024

In many metal forming processes, certain texturization of the tool is necessary to have some friction that can make the operation possible. One example of that is the use of crosshatching methods on cemented carbide punches to manufacture beverage cans. The deep drawing and ironing process of the aluminum foil during can production involves different wear mechanisms being active on the punch surface, i.e. microabrasion and metal transfer. The present work examines the abrasive wear performance and friction characteristics of two cemented carbide grades by means of scratch and linear reciprocating sliding wear testing with Al2O3 counterparts under dry and lubricated conditions, with smooth polished and textured cemented carbide surfaces respectively. Additionally, well-controlled tests in which an aluminum pin is sliding over the cemented carbide surface were performed to evaluate the initial metal transfer. Post-test characterization shows the influence of carbide microstructure on the friction, material transfer and wear
Grain Refinement And Texture Randomization In Austenitic Stainless Steels Produced By L-PBF
Authors: Monier Leo , Despres Arthur , Martin Guilhem , Blandin Jean-Jacques , Veron Muriel
Published: November 2024

Additive manufacturing is an opportunity for the energy field to produce sophisticated geometries. However, there are still several roadblocks to its use to make a wide variety of parts. One needs to demonstrate that parts produced with conventional processing routes can be substituted by parts fabricated by additive manufacturing. Parts made of 316L stainless steels have been fabricated using two different powder batches while keeping the exact same processing conditions. The nominal composition of the two initial powder batches differs slightly, but it led to very different microstructures. Powder batch 2 leads to a finer grain structure that goes along with texture randomization. The underlying mechanism responsible for grain refinement and texture randomization is discussed and can be considered as an alloy design strategy in the framework of additive manufacturing.
Geometry Diversity In MoldJet®, A Sinter-based Additive Manufacturing Process
Authors: Teuber Robert , Weißgärber Thomas , Andersen Olaf , Studnitzky Thomas
Published: November 2024

The MoldJet process is a new and innovative, sinter-based additive manufacturing process that combines two generative process steps. This synergy enables an enormous variety of shapes from small filigree to large-volume 3D-printed metal parts. Many comparable AM processes specialise in just one spectrum of geometries or are limited by the printing process and following process steps. The MoldJet process offers the possibility of producing different component geometries not only simultaneously, but also without the use of support structures made of part material. In this paper, the application range of the process is presented. On the basis of evaluation geometries, it is analysed where the minimum for wall thicknesses at the printing process lies. On the other hand, component geometries with large external dimensions on the one hand and large-volume component areas on the other hand are produced and limitations with regard to the printing process are also determined here.
Relationship Between Powder Properties And Powder Layer Quality In Powder-bed-based Additive Manufacturing Processes
Authors: Soulier Mathieu , Burr Alexis , Roumanie Marilyne , Laucournet Richard
Published: November 2024

The powder spreadability drives the robustness of powder-bed-based additive manufacturing processes (laser powder bed fusion and binder jetting) as well as the performance of the printed parts.This work describes relations between powder characteristics and powder layer properties. To this end a database including more than 50 stainless steel powders characterizations is analysed to establish an analytical model linking the particles sizes and shapes with the flowability and powder packing respectively determined by the avalanche angle and apparent density.The consecutive powders spreadability is assessed on an automated spreading bench, instrumented to estimate the powder layer roughness and density in representative conditions of printers. This bench enables to test different spreading speed, and spreading tool (rake or roller) to cover main printer configurations.The statistical analysis of powder characterizations and powder layer properties establishes a nonlinear regression using least square functions. The predictions of the analytical models are discussed.
Pixel Intensity Of Near-infrared Long-exposure Images Acquired In-situ As A Quality Control Tool In Laser Powder Bed Fusion Of Ni-base Hastelloy X
Authors: Schwerz Claudia , Nyborg Lars
Published: November 2024

Reliability improvement of laser powder bed fusion relies on implementing in-situ process monitoring and control. One of the monitoring systems that has shown promising advances towards this goal is optical tomography based on long-exposure near-infrared layerwise imaging. The system outputs grayscale images that require adequate processing to flag undesirable deviations. This study aims to assess the viability of analysis of pixel intensity values to identify systematic internal defects. Hastelloy X specimens were manufactured with varying process parameters to generate varying defect types and contents. The outputs of the monitoring system were used for estimating the defect content in the specimens. The results show the suitability of pixel intensity analysis to discriminate processability and occurrence of systematic defects to have limited applicability, which is attributed to the predominant influence of process parameters in the pixel intensity values.
Rapid Verification Of Two Important Microstructural Parameters Of Cemented Carbides Through Two-dimensional Characterization
Authors: Fang Shiqi , Salán Ballesteros Núria , Llanes Luis
Published: November 2024

Cemented carbides or hardmetals are ceramic-metal composites usually consisting of tungsten carbide particles bound by a cobalt-base alloy. They offer an outstanding range of property combinations depending on their effective microstructural assemblage. Hence, reliable microstructural characterization becomes essential for hardmetal selection and quality control. In practice, the two important microstructural parameters (phase ratio and grain size) are often estimated by a statistical estimation or qualitative classification. This work aims to verify them through two-dimensional characterization using easy-obtained inspecting facilities. Accordingly, optical microscopy was applied to acquire surface images grades after the metallographic processing, and line and area analysis methods were applied. It is found that these methods could offer relatively reliable microstructural information, and the line analysis was proven more suitable and precise for the rapid verification. The characterization of carbide grades with a size in submicron might be limited by the resolution of the optical microscopy.
Ti(C,N)-based Cermets For Sawblades: Preparation, Properties, Testing And Upscaling
Authors: Scagnetto Fabio , Lengauer Walter
Published: November 2024

A Ti(C,N)-based cermet grade for sawblade production was developed, targeting performance of commercially available grades. Firstly, laboratory investigations focused on commercial cermets compositions and properties. Subsequently, a variety of laboratory grades were prepared and characterised (HV10, KIC, LOM and SEM, HC, MS, CGHE, DTA, XRF). Some deeper analysis was done on individual grades and formulations (XRD, WDS-EPMA, EGA-MS). A set of such optimised cermet prototypes was prepared in the laboratory and brazed to sawblades. The results were used for further development of the grades, moving step-by-step to industrial upscaling into cermet production. After each step, cutting tests were performed to check the cutting performance in real conditions. Starting from almost 50% tool life of laboratory grades as compared to a commercial grade, systematic improvements enhanced the cutting performance of the grade developed in this study to outperform the commercial cermet target grade.
Fatigue And Reliability Of MIM 42CrMo4
Authors: Schneider Markus , Schwarz Jack , Simon Christian , Schütz Wolfgang , DeNicolo Alessandro
Published: November 2024

MIM 42CrMo4 is a versatile low alloy steel and commonly used in the forging industry. Its properties can be varied with a tailored hardening and tempering treatment over a wide range of strength|ductility combinations. Its high ductility is beneficial for gears, connecting rods, crankshafts, pistons and other automotive and machinery components. This makes that steel grade also attractive for the Metal Injection Molding and Additive Manufacturing industry. Therefore, MIM 42CrMo4 hardened was chosen as third material – after MIM 8620 case-hardened and MIM 100Cr6 hardened – for the internal high cycle fatigue and notch sensitivity study. As presented in the years before, two different injection molding methods and resulting weld line positions were compared. Moreover, the mean stress sensitivity, notch sensitivity, scatter and further s-N line parameters were discussed and compared with the previously characterized MIM steel grades. Its response on a variety of tempering regimes was investigated too.
A Comparative Investigation On Shape Accuracy Of Space Parts Produced By Different L-PBF Processes And AlSi10Mg Powders
Authors: Strandh Emil , Blackwell Cameron , Turner Nathanael , Meisnar Martina , Pambaguian Laurent , Lockowandt Christian , Daab Dominique , Heikkilä Irma
Published: November 2024

The effect of variability of metal laser powder bed fusion (L-PBF) processes and raw materials for the shape accuracy of the part is a poorly understood area. A suite of designs covering bulky designs of complex shape and delicate fine features were created and manufactured by different machine hardware, process parameters and four AlSi10Mg powders sourced from different suppliers. The designs were relevant for use in space applications. The aim was to evaluate the relationship between the process and powder characteristics for the shape accuracy using a systematic approach for the investigation. The results showed the shape accuracy was clearly connected to the applied process and indirectly to the powder.
Experimental Investigation Of The Relationship Between Powder Geometry And Pore Ratio Of Mg Powders Sintered By FAST
Authors: Aydin Sohret Melda , Tekin Tugçe , Ipek Rasim
Published: November 2024

Commercial purity Mg powders were sintered at 300°C for 15 minutes with alternating current electric field-assisted sintering technique (FAST) under the pressure of 30 MPa after mechanical milling for 4-8-12-16-20 hours. Powder geometries, sizes and microstructural properties of the powders were investigated depending on the milling time. The relationship between the pore ratio and pore structure of the sintered samples and their powder geometries was investigated. Depending on the powder microstructure and geometry, the realization mechanism of FAST has been examined and evaluated with the results of compressive strength and hardness tests. The results were supported by optical microscope images, Scanning Electron Microscope (SEM) images. It has been determined that powder geometries (platy-spherical) -especially in the FAST method- have a great effect on sinterability and pore size, shape, and distribution.
Numerical Modeling Of Powder Spreading In Additive Manufacturing Processes
Authors: Burr Alexis , Stephan Maxime , Soulier Mathieu
Published: November 2024

The powder bed properties are of main interests in additive manufacturing processes. Particularly, it is paramount to ensure a correct density of the powder bed as this will have an impact on the final part properties. In this work, we propose to model the deposition of powder by the discrete element method through an elastic contact law (using the EDEM software from Altair with GPU acceleration). Different particle size distributions are used with different recoating strategies, so as to estimate the effect of the mean particle size, recoater speed and nominal layer thickness on the powder bed density and segregation. Those two quantities evolve similarly with the increase of layer thickness, whatever the particle size distribution. Only the segregation is observed to have a larger impact for wider particle size distribution.
Advanced Lubricants For Modern PM Applications
Authors: Wimbert Lars , Lindenau René , Lindsley Bruce , McQuaig Kylan
Published: November 2024

Most mechanical properties of powder metallurgical (PM) components significantly depend on the part’s density. Considering the higher complexity of modern PM parts and the demand for higher strength with less weight, increased green and sintered densities are required. The development of new advanced lubricants is one key factor for this, providing additives with superior lubricity, clean burn-off and unsophisticated usability. This contribution documents recent developments in lubricant technology with experimental results from lab scale to serial production. The presented lubricant solutions allow powder compaction to higher density levels using lower lubricant additions without the need for heated tooling into a tight temperature range. Especially for complex shaped parts, the broader temperature range helps to keep the lubrication sufficient for tool sections with higher friction, resulting in ejection pressures less than 50% of the values seen for amide waxes.
Modelling Of Delta-ferrite Transformation Effect On The Sintering Behavior Of 316L Binder Jetting Components
Authors: Cabo Rios Alberto , Hryha Eduard , Olevsky Eugene , Persson Mats
Published: November 2024

The main objective of this study is to develop a simulation methodology that accounts for phase transformation (δ-ferrite) during the sintering of 316L stainless steel binder jetted (BJ) components. The model was based on the continuum theory of sintering develop by Skorohod and Olevsky. Dilatometry sintering tests at different heating rates up to 1370°C were performed. The constitutive parameters for the sintering model were obtained by dilatometry data analysis. Dilatometry results at different heating rates showed minor influence of the δ-ferrite transformation kinetics on the material viscosity. Thus, a new temperature-dependent material viscosity function was proposed to include the δ-ferrite transformation. The new model proposed was used to predict the densification behaviour of 316L BJ samples subjected to dilatometry experiments at different temperatures and times. The influence of δ-ferrite on the densification was accurately predicted for the material and sintering conditions studied.
Microstructural Analysis And Mechanical Properties Of Fe Based Shape Memory Alloy Manufactured By Laser Powder Bed Fusion
Authors: Gómez Raúl , Garciandia Fermin , Taboada Maria del Carmen , San Sebastian Maria , Mancisidor Ane Miren
Published: November 2024

Shape memory alloys (SMAs) are smart materials capable of recovering their original shape after being deformed by applying some stimuli. This effect occurs as a results of the martensitic transformation between the austenitic and martensitic phases. This unique characteristic make these materials appropriate to use in medical applications such as stents and for actuators. Fe based SMA are attractive alloys from cost perspective in contrast to the more common NiTi material. Additive manufacturing appears as a potential manufacturing process since it offers the possibility to fully exploit the attractive functionalities of SMAs.In this work, the processability of Fe based SMA by laser powder bed fusion has been studied. The microstructure has been analyzed by scanning electron microscopy and EBSD in as-built and after a heat treatment. Mechanical properties have also been determined. The resulting phase proportions responsible of the martensitic transformation is greatly dependent on the applied laser energy.
Estimating PM Gear Fatigue Strength From Bending Fatigue Data
Authors: Andersson Michael
Published: November 2024

Gears are an interesting application for pressed and sintered applications, and having accurate fatigue data is often a pre-requisite for starting a new gear design. Ideally gear fatigue strength is tested on gears, but that is not always possible. At the same time standard bending fatigue data are often more readily available. Therefore, it’s interesting to have reliable methods for going from, for instance, bending fatigue strength on a test bar to tooth root fatigue strength of a gear. This paper investigates how gear fatigue strength can be calculated from test bar data and the results are compared with pulsator testing of gears.
Industrial Development And Verification Of Cr-Mo-V Based Cold Work Tool Steel Parts Produced Via Electron Beam Melting (EBM)
Authors: Selte Aydin , Oikonomou Christos , Åsberg Mikael , Strandh Emil
Published: November 2024

Being a fast, powerful and crack-free manufacturing process, electron beam melting (EBM) has been gaining importance for tooling industry for the recent years. EBM allows processing high melting materials under vacuum atmosphere with high building rates, which offers less residual stresses caused by the complex thermal history and high cooling rates during the manufacturing.Uddeholms AB has previously shown on a pilot scale the performance capabilities of the EBM process in respect to the high alloyed and commercially available tool steel powder grade Vanadis® 4 Extra AM. In this study, industrial scale demonstrators and application tools were produced from Vanadis® 4 Extra AM powder. Industrialization of the concept studies was completed. Verification of the parts were conducted by using a slider-on-flat-surface (SOFS) wear tester and a semi-industrial punching test. Moreover, the dimensional tolerances, need of post-processing treatments and product qualities were emphasized within the scope of this investigation.
Effect Of Gas Atomised Powder Characteristics On The HIPped Astroloy Properties
Authors: Aristizabal Miren , Galech Unai , Sarasola Miren , Soler Rafael , Paños Estibaliz , Iturriza Iñigo
Published: November 2024

Gas atomised powder is widely used for HIP applications thanks to its beneficial properties in terms of flowability, compactability and few interstitials. Generally, a wide range of powder particle size is used in HIP to increase the powder efficiency, flow and compaction. While thin particles have to deal with oxygen pick up, wider powders suffer from entrapped gas porosity. These issues have been analysed and related with the properties of HIPped high temperature Ni superalloy. Characterisation have been carried out by mean of chemical analyses, microstructural analyses and mechanical tests. Results show that thin powders are prone to form PPBS and large powders have higher content of argon and both led to a ductility reduction. As a conclusion, gas atomised powder combining wide particle size range showed the best property compromise for Astroloy, making it suitable for the production of elevated temperature components for high-efficiency new jet engines.
Opportunities Of Physics-Based Multi-Scale Modeling Tools In Assessing Intra-grain Heterogeneities, Polycrystal Properties And Residual Stresses Of AM Metals
Authors: Lindroos Matti , Pinomaa Tatu , Laukkanen Anssi , Antikainen Atte , Lagerbom Juha , Reijonen Joni , Lindroos Tomi , Andersson Tom
Published: November 2024

Microstructure is the origin of the properties and performance for additively manufactured metals. Rapid solidification enable the formation of various grain|phase structures as well as solute segregation and initial dislocation structures that all contribute to the properties of the alloy. We present the following methods in this work. An effective way to approach process-structure-properties linkage in rapid solidification is to utilize a phase field solidification model coupled with a thermomechanical crystal plasticity. This allows us to assess both intra-grain|polycrystal level dislocation|stress heterogeneities introduced during solidification and residual stresses. Single-track laser melting is a method to analyze materials printability. In this scope, crystal plasticity is a tool to investigate heterogeneities and cracking tendency of solidified microstructures during cooling. Finally, at the part level it is possible to utilize homogenized|embedded crystal plasticity models to provide the thermomechanical response of the material. We review the pre-mentioned multiscale model outputs, interactive dialogue, and opportunities.
Additive Manufacturing Of Metal Parts Using Industrial MIM Feedstocks
Authors: Fonta Didier , Deshons Thibaud
Published: November 2024

Characterization of metal 3D printed parts produced by direct MIM feedstock extrusion.
The Influence Of Cu Pre-alloying And Its Precipitating Behavior On The Compressibility And Hardenability Of Fe-Mo Alloyed Steel Powder
Authors: Takashita Takuya , Unami Shigeru
Published: November 2024

Both compressibility and hardenability are required for the alloyed steel powder for the as-sintered process. In this research, the Cu pre-alloying for the Fe-Mo alloyed steel powder, which has good compressibility, is investigated for improving hardenability. As a result, the unique phenomena was found that both compressibility and hardenability of the Fe-Mo alloyed steel powder was improved by Cu pre-alloying. And the mechanism of the phenomena was investigated by the TEM observation. The size of Cu precipitates in Fe-Mo alloyed steel powder increased with an increase in Cu pre-alloying, and it improved the compressibility. In addition, Cu precipitates were solute into the matrix of the sintered microstructure during sintering, and solute Cu improved the hardenability. As a result, the as-sintered material with bainite and martensite microstructure was obtained. Because of these improvements of the compressibility and the hardenability, higher strength as-sintered material was obtained compared with conventional as-sintered material.
Toward The Reduction Of Heavy Rare Earth Elements In High Performance NdFeB Permanent Magnets By The Refinement Of The Strip Cast Flakes Microstructure
Authors: Luca Sorana , Brombacher Christoph , Lavarenne Laetitia , Genevrier Stephane , Leforestier Jean , Dayde Hugo , Tosoni Olivier , Rado Cyril
Published: November 2024

Sintered NdFeB permanent magnets (PM) are essential components of electrical machines that require a high energy product|volume ratio for weight reduction and better reliability. However, to compensate the decrease in magnets coercivity with temperature, substitution of Nd by Heavy Rare Earths (HRE) is widely used at industrial scale. This approach seriously increases the dependence on these critical raw materials in EU magnet industry.This work focuses on the reduction of HRE elements in the high performance NdFeB PM, by the refinement of the microstructure of the alloys. The proposed optimization of the NdFeB alloys can boost development of fine-grained NdFeB PM’s allowing a significant HRE reduction. The influence of the process parameters as well as of the alloys composition on the coercivity increase will be emphasized. Coercivity increase of 110 kA|m at 150°C have been demonstrated for magnets based on alloys with optimized microstructure and composition.
Influence Of Laser Power On The Corrosion Behavior Of An Mg-Y-Nd-Zr Alloy Produced By Powder Bed Fusion - Laser Beam
Authors: Nilsson Åhman Hanna , Wahman Clarence , Mellin Pelle , Persson Cecilia
Published: November 2024

Powder bed fusion – laser beam (PBF-LB) of Mg-Y-Nd-Zr alloys has recently been gaining increasing attention for the development of biodegradable orthopedic implants with optimized mechanical properties and enhanced biocompatibility. However, the corrosion rates remain too high. Thus, the goal of this study was to investigate the influence of the laser power on the structure and microstructure of as-built Mg-Y-Nd-Zr surfaces and the resulting corrosion properties over 28 days. Samples were produced with three different laser powers (60W, 80W and 90W), while keeping all other parameters constant. The 60W samples had the best corrosion resistance, despite having a higher surface roughness. At higher energy input there is an increase in magnesium evaporation, which causes an increase in the amount and size of secondary phases, and thus an increased micro galvanic corrosion. This study gives an important insight into the influence of the PBF-LB process on the corrosion properties of Mg-Y-Nd-Zr alloys.
Correlation Between Air Humidity And Adsorbed Water And Their Influence On Well-known And Modern Powder Characteristics
Authors: Mitterlehner Marco , Gschiel Harald , Tomisser Manuel , Schatz Michael , Weingrill Helena , Aschl Timothy
Published: November 2024

When it comes to the characterization and processing of metal powders used in laser beam powder bed fusion (LB-PBF) processes, moisture has been a recurring topic for quite some time. In general, a distinction must be made between water from the air surrounding the metal powder and water adsorbed on the metal powder surface. To investigate the actual influence of these two water sources, a gas atomized superalloy powder BÖHLER L718 AMPO was exposed to different humidity levels and examined under these conditions. Thus, the correlation between the prevailing air humidity and the adsorbed water content on the metal powder surface and further, the influence on well-known (flow time and apparent density) as well as modern (shear cell parameters such as the flowability coefficient) powder characteristics was investigated. The water content adsorbed on the metal powder surface was determined by Karl Fischer titration.
Influence Of Boron On Stress-rupture Behavior Of A Modified HastelloyX Produced By Powder Bed Fusion-laser Beam
Authors: Deirmina Faraz , Koenig Slawomir , Saeidi Kamran , Oscarsson Eva , Johansson Lennart , Adegoke Olutayo
Published: November 2024

HastelloyX is one of the most common materials used in powder bed fusion-laser beam (PBF-LB) to fabricate components operating at elevated temperatures. Boron is a key element in enhancing the creep properties of superalloys at high temperatures, however, similar to the welding practice, boron might impose a negative effect on the printability. In the present work, the influence of boron on stress-rupture behavior of a modified low carbon HastelloyX variant was studied. Powders with boron contents varying from 2 to ~20 ppm were used to fabricate the samples. Time to rupture, elongation, and reduction of area were obtained from isothermal stress rupture tests performed at 816°C with static load of 103MPa. In view of the fracture mechanism, and the stress-rupture test results, it can be concluded that increasing the boron content while decreasing the total grain boundary area of the printed material improves time-to-rupture during isothermal stress-rupture test.
Cost Effective Sensor Fusion Approach For Laser Metal Deposition
Authors: Arejita Beñat , Garmendia Iker , Isaza Juan Fernando , Zuloaga Aitzol
Published: November 2024

The complex nature of an LMD process demands advanced control mechanisms in order to compensate for the deviations that occur in the growth direction of the material. Consequently, every layer must be scanned to measure the 3D profile as layers are deposited, either by complicated in-situ measurement techniques or by performing intra-layer measurements after each layer deposition. Additionally, the digitization of the process allows the extraction and logging of relevant data and available process control and state variables for an ex-post analysis of the manufactured object. The quality of the extracted data directly affects the quality of the process itself, and typically high-end surface profilers are used, resulting in costly solutions. This work proposes an LMD process control solution that applies sensor fusion techniques to extract and integrate data from several cost-effective sensors. As a result, data-rich layer information is generated by combining process metadata and measured layer profiles using.
Coated Elemental Cu Powders With Improved Absorbance In Red Light Laser Sources
Authors: Ceroni Marta , Maddalena Lorenza , Carosio Federico , Actis Grande Marco
Published: November 2024

Cu powders show high reflectivity when exposed to a laser having wavelengths in the range of 1064-1080 nm, hindering the processability when manufacturing by red-light laser powder bed fusion. Green or blue lasers help overcoming this issue, as well as the change of the chemical composition of the powder. However, other approaches may also be used. The present paper analyses the effect of coatings applied on elemental Cu-powders on the absorbance of the resulting material. Different amounts of Graphite Oxide have been deposited on the surface of metal powders by a nanocoating approach. The prepared powders have been characterized evaluating the absorbance in the red, green, and blue light wavelengths using UV-Vis spectroscopy. The uniformity of GO coating was also evaluated by scanning electron microscopy and Raman spectroscopy.
Numerical Design Of High Entropy Super Alloy Using Multiscale Materials Modeling And Deep Learning
Authors: Andersson Tom , Laukkanen Anssi , Suhonen Tomi , Lindroos Matti , Pinomaa Tatu , Kaipainen Joni
Published: November 2024

A new alloy designed for high temperature application with multiscale material modelling and deep learning is presented. Calphad type of analysis are combined with DFT simulations and tied together with machine learning tools are utilized in order to find the most promising alloy composition. Designed alloy is synthesized and test specimens are produced with laser powder bed fusion. Experimental material and mechanical characterization methods are compined wiht simulation tools to create a micromechanical model that is used for mechanical property and performance simulations. A workflow is created to combine the different length scales in order to asses the performance of the final component already in alloy design phase in such a way that the alloying components can be fine tuned to fulfill the design requirements of the respective products.
Towards The Upscaling Of ODS Steels: STARS ROUTE®
Authors: Ordas Nerea , Roldan Marcelo , Leon Edgar , Leguey Teresa , Cardozo Evelin , Iturriza Iñigo
Published: November 2024

14Cr-2W-0.3Ti-0.3Y2O3 Oxide Dispersion Strengthened (ODS) Ferritic Stainless Steels are promising candidates for structural components in future nuclear systems. Their outstanding properties are attributed to an ultrafine microstructure and a very stable dispersion of Y-Ti-O oxide nanoparticles (NPs).The STARS Route® developed to produce ODS alloys avoids the need for mechanical alloying to dissolve the oxide-former elements in the matrix and relies on Ceit’s capability to introduce them during gas atomization as oversaturated solid solution. Warm rolling after HIPing introduces a high density of dislocations, preferential nucleation sites. Final annealing heat treatment precipitates the NPs through an internal oxidation process: the metastable oxides formed at the surface of powder particles after atomization dissociate, and oxygen, Ti and Y diffuse towards the dislocations, where they precipitate as Y-Ti-O nano-oxides.This work shows the microstructural evolution of ODS steels obtained with the STARS Route®, and the role of process parameters on mechanical properties.
A Etnobotânica e o Ensino de Ciências na Educação Básica: possíveis diálogos
Authors: Rocha Kenny de Souza , Forsberg Maria Clara da Silva
Published: November 2024

A Etnobotânica tem como dorsal propósito compreender a relação entre as plantas e as culturas humanas. Nessa perspectiva, objetivou-se realizar uma revisão integrativa da literatura nas publicações do repositório CAPES no período de 2013 a 2022, acerca da incorporação dos conhecimentos tradicionais sobre plantas no Ensino de Ciências da Educação Básica. Aplicados critérios de inclusão e exclusão, elegemos 13 trabalhos para inferência e interpretações que resultaram em duas categorias: Etnobotânica: diálogo socioambiental e Etnobotânica: diálogo sociocultural. Concluímos que a Etnobotânica proporciona o diálogo entre o conhecimento tradicional e científico no âmbito do ensino de ciências da educação básica, ampliando a visão dos discentes, estimulando novas descobertas e potencializando a aprendizagem para um ensino pautado numa abordagem sociocultural e socioambiental.
Representações sociais de lingerie: um estudo com alunos e instrutores/colaboradores do SENAI Espaço da Moda e com empresários do setor de Nova Friburgo/RJ
Authors: Torres Ana Carla , Lima Rita de Cássia Pereira
Published: November 2024

A pesquisa foi desenvolvida na região de Nova Friburgo/RJ, conhecida como polo de moda íntima. Devido à presença constante do tema nesse ambiente social, considerou-se relevante compreender a construção de significados sobre lingerie por grupos diversos na cidade, com fundamentação na Teoria das Representações Sociais, desenvolvida por Serge Moscovici. Nesse contexto, o objetivo do presente estudo é investigar representações sociais da lingerie por alunas e instrutores/colaboradores do SENAI Espaço da Moda e por empresários em Nova Friburgo/RJ. Foram realizadas 10 entrevistas semiestruturadas com cada grupo, analisadas com o apoio da análise de conteúdo temática. Para as alunas, lingerie é “trabalho”, essencial para a sobrevivência; para os instrutores/colaboradores, é sinônimo de “liberdade”; e, para os empresários, é o “DNA” da cidade, pois proporciona solidez para as empresas. A pesquisa revelou que a lingerie pode ser compreendida por meio de suas representações, expressas em processos sociocognitivos de grupos que refletem sua história e seu contexto social.
Feminist Killjoy…But With a Heart
Authors: Gandhi Ankita
Published: November 2024

India is currently witnessing a spate of protests against gender-based violence targeted towards women. The rape and murder of a trainee doctor in Kolkata, allegations against influential figures of the Malayalam film industry, and wrestler Vinesh Phogat’s accusations of sexual harassment against BJP leader Brij Bhushan Sharan Singh have led to demands for stricter legal consequences. However, I urge feminists to eschew reliance on the punitive state. It is paramount that feminists “break the wheel” and not adopt the tools of the oppressor by advocating for punishment, shame, and stigma.