World PM2022 Proceedings

Authors:

Rafael Cury (Plansee Tungsten Alloys, France), Pascal Mahot (Plansee Tungsten Alloys, France), Heinrich Kestler (Plansee, Austria)

Abstract:

Amour Piercing fin-stabilized discarding sabot is a type of a non-explosive kinetic energy penetrator ammunition used on anti-tank weapons. It requires material showing remarkable characteristics such as high density, high mechanical and impact resistance in order to provide the best penetration possible against targets. Tungsten Heavy Alloys are commonly used for this type of penetrators. Recently, with the increasing interest on Tungsten Heavy Alloy additive manufactured parts, it became mandatory to investigate the influence of this process on material properties. Thus, additive manufacturing was used to obtain bars, which were submitted to solid-liquid sintering under hydrogen and processed under vacuum to avoid embrittlement. These alloys were fully characterized with respect to their microstructure and mechanical characteristics. Results shown that additive manufacturing is a viable process for this type of alloys.

DOI:

https://doi.org/10.59499/WP225371922

Authors:

Sebastian Riecker (Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Branch Lab Dresden, Germany), Robert Teuber (Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Branch Lab Dresden, Germany), Anne Mannschatz (Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Germany), Bernhard Müller (Fraunhofer Institute for Machine Tools and Forming Technology, Germany)

Abstract:

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 <5 µm.

DOI:

https://doi.org/10.59499/WP225371432

Authors:

Saeed Khademzadeh (Chalmers University of technology, Sweden), Yijun Zhou (Uppsala University, Sweden)

Abstract:

Additive Manufacturing of non-assembly metallic mechanisms is highly desirable because of their potentially higher performance and low costs due to enhanced structural features and the reduced need for labour-intensive procedures. However, fabrication of such mechanisms using metal AM techniques faces many challenges. For instance, down-skin inclined surfaces suffer from an insufficient quality due to the staircase effect and partially melted attached powder particles that may deteriorate the function of the mechanism since residuary stuck material can block the clearance space. In this work, a novel scanning strategy was employed for the fabrication of non-assembly functional micromechanisms. A threshold angle was defined for activation of a new set of process parameters for down-skin surfaces. Non-assembly ball joints were additively manufactured using laser powder bed fusion technology. The effects of threshold angle, overlap between in-skin and down-skin surfaces, and input energy on the functionality of non-assembly joints was investigated using micro-computed tomography

DOI:

https://doi.org/10.59499/WP225371467

Authors:

Kay Reuter (Fraunhofer IFAM Dresden, Germany), Inge Lindemann-Geipel (Fraunhofer IFAM Dresden, Germany), Thomas Studnitzky (Fraunhofer IFAM Dresden, Germany), Olaf Andersen (Fraunhofer IFAM Dresden, Germany), Thomas Weißgärber (Fraunhofer IFAM Dresden, Germany), Raphael Koch (Ford Werke GmbH, Germany)

Abstract:

Energy-efficient electric motors are crucial for the progress of electromobility. Soft magnetic materials with a high silicon content, such as Fe6.5Si, offer the possibility of high electrical resistance, high saturation magnetization and comparatively low power losses. However, due to the brittleness of Fe6.5Si, this material cannot be processed using conventional manufacturing methods (such as stamping). By means of 3D screen printing process, this material can be processed through a powder metallurgical processing route. Thus, electric steel sheets with low thickness, high alloying content and high productivity can be realized. We present results of printed and sintered Fe6,5Si electric steel sheets with thicknesses between 100 and 350 µm. The power loss can be reduced below 35 W kg-1 at 1000 Hz and 1 T. The magnetic properties of the sheets will be discussed in dependence on the sintering parameters and the powder properties.

DOI:

https://doi.org/10.59499/WP225371624

Authors:

Didier Fonta (Pollen AM, France), Thibaud Deshons (Pollen AM, France)

Abstract:

Characterization of metal 3D printed parts produced by direct MIM feedstock extrusion.

DOI:

https://doi.org/10.59499/WP225371995

Authors:

Lars Wimbert (GKN Powder Metallurgy, Germany), René Lindenau (GKN Sinter Metals Engineering GmbH, Germany), Kylan McQuaig (Hoeganaes Corporation, USA)

Abstract:

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.

DOI:

https://doi.org/10.59499/WP225371442

Authors:

Jean-Michel Missiaen (Univ. Grenoble Alpes, France), Nicolas Botter (Safran SA, France), Yvan Avenas (Univ. Grenoble Alpes, France), Rabih Khazaka (Safran SA, France)

Abstract:

An assembly for power electronics based on the deposition and pressureless sintering of successive silver layers on an Aluminum Nitride heat sink has been developed. Sintered silver layers act as die attach, current tracks and adhesion layer on the ceramic. This assembly has the advantage to give sintered joints with a high mechanical strength and a high thermal conductivity compared to standard brazing alloys at the highest operating temperature of semiconductor components (200°C). In this paper, aging of the silver tracks and die attach layers is studied. A significant coarsening of the microstructure is observed in confined areas, under the chip and|or far from the external surface, after 200h annealing in air at 200°C, whereas coarsening is essentially inhibited in argon atmosphere. The shear strength and thermal properties of the sintered joint are improved after thermal storage in air. Mechanisms of the microstructural evolution and microstructure-properties relationships are discussed.

DOI:

https://doi.org/10.59499/WP225372071

Authors:

Shweta Singh (Indian Institute of Technology Bombay, India), Ankit Gurjar (Indian Institute of Technology Bombay, India), Eshant Bhatia (Indian Institute of Technology Bombay, India), Ishita Krishnatrey (Indian Institute of Technology Bombay, India), Seema Negi (Indian Institute of Technology Bombay, India), Parag Bhargava (Indian Institute of Technology Bombay, India), Rohit Srivastava (Indian Institute of Technology Bombay, India)

Abstract:

The motivation of this work is to improve fracture toughness and incorporate anti-microbial characteristics in alumina ceramics. In this work, alumina-silver composites are prepared by the addition of 2, 5, 10, and 15 wt. % silver nano-flakes. The microstructural analysis is performed using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Mechanical properties like flexural strength, fracture toughness, and microhardness are evaluated. Flexural strength is found to decrease with increased silver content while fracture toughness improved significantly. Antibacterial properties are evaluated on E.coli bacteria. All the samples showed antibacterial activity which improved with increased silver content. The present study establishes alumina|silver composite as an antibacterial material with improved fracture toughness which makes it a potential biomaterial for dental and low load-bearing applications.

DOI:

https://doi.org/10.59499/WP225371864

Authors:

Moritz Greifzu (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Fabian Peter (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Tarang Dineshchandra Mehta (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Joanna Eckardt (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Sohan Acharya (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Axel Marquardt (Technische Universität Dresden, Germany), Lukas Stepien (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Elena Lopez (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Frank Brückner (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany), Christoph Leyens (Fraunhofer-Institut für Werkstoff- und Strahltechnik IWS, Germany)

Abstract:

Binder jetting (BJ) is a sinter-based additive manufacturing technology with several advantages over laser or electron beam-based powder bed processes. This includes faster build rates, non-necessity of support structures and no introduction of thermal stress into the part during the build. On the other hand, BJ parts shrink considerably during sintering making it more challenging to produce parts within tolerances. Recently, software to simulate and compensate this distortion has been commercialized. Since the algorithm is based on a phenomenological model, experiments have to be conducted to feed material parameters into this model for correct simulation of a specific alloy. Here, an experimental approach is presented using dilatometry and in-situ gravitational beam bending to perform a full characterization of stainless steel powder 316L , and the extraction of the relevant data for the simulation.

DOI:

https://doi.org/10.59499/WP225371941

Authors:

Lea Reineke (Fraunhofer IFAM, Germany), Bastian Barthel (Fraunhofer IFAM, Germany)

Abstract:

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.

DOI:

https://doi.org/10.59499/WP225367722

Authors:

Koji Nakamura (Kyushu University, Japan), Isshin Ando (Kyushu University, Japan), Masatoshi Aramaki (Kyushu University, Japan), Fei Jiang (Yamaguchi University, Japan), Takeshi Tsuji (the University of Tokyo, Japan), Kosuke Ashizuka (JFE Steel Co., Japan), Masayuki Uesugi (Japan Synchrotron Radiation Research Institute (JASRI), Japan), Akihisa Takeuchi (Japan Synchrotron Radiation Research Institute (JASRI), Japan), Yukiko Ozaki (Kyushu University, Japan)

Abstract:

For a high-density pure iron sintered compact without open pores, the 3D pore configurations at different strain levels during ductility tests were visualized by X-ray computed tomography (CT). In addition, each three-dimensional structure was quantified as a two-dimensional scatter plot, persistent diagram, by 1st persistent homology (PH) analysis. By comparing the scatter plots, specific local pore configurations sensitive to changes in strain were extracted. The results showed that, just prior to fracture, adjacent closed pores formed pore-clusters and coalesce to each other into larger pores. This process is consistent with the theory of ductile fracture of the void model proposed for wrought metals.

DOI:

https://doi.org/10.59499/WP225372227

Authors:

Andrey Shulga (National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Russia)

Abstract:

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

DOI:

https://doi.org/10.59499/WP225369660