EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Copper and its alloys play an elementary role in industrial applications due to their excellent thermal and electrical conductivity. In the field of electromobility, plugs made of copper materials are used as connecting elements between the charging station and the vehicle. Another example is the application of precipitation-strengthened copper alloys, e.g., CuCr1Zr and CuNi2SiCr, for...

With the growing industrial application of laser-based powder bed fusion (LB-PBF) there has been an increase in the amount of powder suppliers and powder grades. Despite similar atomizing technology, the quality of the powder feedstock can vary significantly between suppliers and batches in terms of powder flowability, impurities and powder surface chemistry. While high quality powder has its...

Given nearly ambient temperature conditions in laser powder bed fusion (LPBF), spatter accumulation is usually the main source of powder degradation. Spatter particles are normally molten/partially molten or overheated particles ejected from the melt pool and its vicinity, that are oxidized due to the presence of residual oxygen in the build chamber. Melt pool ejections are finer and have a...

In the past decade, the industrial interest for Laser Powder Bed Fusion (LPBF) additive manufacturing (AM) process has significantly grown and the technology is on track for full scale production. Yet some key mechanisms of the process are not fully understood. To create a new layer, the powder is deposited on a previously solidified layer. This volume of powder defines the available amount of...

The powder as raw material, either for powder bed or blown powder technologies, constitutes an important strategy in metal additive manufacturing (AM). Metal powder used for powder bed fusion AM is characterized by high surface reactivity due to the large surface area of the powder that is about 10 000 times larger than the surface if the bulk material of the same mass. This results in the...

In Laser Powder Bed Fusion (LPBF), a significant amount of metallic powder is not melted by the laser beam. Costs and material yield strongly depend on the ability to reuse metal powder efficiently. However, some of the unfused powder is exposed to high temperatures during the manufacturing process in an imperfectly controlled atmosphere. Therefore, there is a need to study and understand...

The development and utilization of metal powder for additive manufacturing processes requires deep comprehension about the complete process chain including atomization, processing and recycling of powder material. Using laser powder-bed fusion, a huge amount of the powder feedstock is left after the process. To increase the efficiency of such processes, it is essential to reuse excess...

In powder bed additive manufacturing technique, the powder characteristics can determine the success or the failure of the job. In the Electron Beam Melting (EBM) process is generally used spherical powder with a particular size distribution of 40-150µm. During the EBM process the powder is spread onto the platform by the rake, therefore is essential to use powders with optimal rheometric...

Selective Laser Melting (SLM) has attracted major interest among the Additive Manufacturing methods (AM). SLM can deliver high manufacturing quality by adjusting production parameters on a given alloy which impacts on the grain structure, phase formation, microstructure, roughness, and porosity. AM aims to achieve superior or even comparable properties to the conventionally manufactured parts....

Although laser based powder bed fusion (LB-PBF) is a prominent additive manufacturing technique, the number of alloys that have been approved for the process remains limited. This is especially true for iron-based alloys such as low-alloy steels, where the high carbon contents of said alloys can promote cold cracking defects. In other carbon-containing iron-based alloys, preheating of the...

Laser Powder bed fusion (L-PBF) has attracted a lot of interest in recent years, not only for its profound advantage of producing metallic components of complex geometries but also for the possibility of manipulating microstructures and crystallographic textures. Additionally, recent observations on wrought austenitic steels have revealed the strong dependence of the transformation induced...

Laser based powder bed fusion (PBF-LB) of metals enables the fabrication of geometrically complex structures, which are difficult or impossible to manufacture with conventional subtractive processing methods. Therefore, economic advantages in terms of enhanced cutting velocities can be facilitated by implementing internal cooling channels in drills or milling cutters made of tool steel....

Wire arc additive manufacturing (WAAM) is a group of technologies suitable for producing large and/or thick parts due to high material deposition and building rates. Among many materials processed by WAAM, austenitic stainless steels, e.g. 316L, are of the most industrially relevant. The microstructure of WAAM 316L thin parts has extensively been studied, however, multiwalled WAAM 316L remains...

The use of additive manufacturing to fabricate metallic components following design optimization as well as the full Design for Additive Manufacturing (DfAM) paradigm, is now a consolidated reality. The ASTMF42 and ISOTC261 -defined powder bed fusion (PBF) and directed energy deposition (DED) processes are able to build metallic components using layer-upon-layer strategies, which are...

Additive manufacturing (AM) is one of the most rapidly developed fabricating techniques over last two decades. The microstructure feature or the residual stress distribution in AM components was widely investigated on its own. However, limited studies were attempted to reveal the correlations between the microstructure and residual stresses in AM components. In this study, high-energy...

Low-alloy steels are one of the alloy systems missing in the materials portfolio of laser based powder bed fusion (LB-PBF). From a LB-PBF processing point of view, this primarily relates to their susceptibility to cold cracking that stems from their elevated carbon contents. There are number of recent works in the literature showing that in-situ annealing through build plate preheating can...

Additive Manufacturing (AM) technologies can realize complex-shape structures, previously not feasible with subtractive manufacturing machines. From Computer-Aided Design (CAD) to a slicing software, which creates a G-code machine routine, it is possible to realize three-dimensional (3D) parts layer by layer. In the past, 3D printing was used only for rapid prototyping due to the required high...

Since additive manufacturing processes typically introduce heterogeneous microstructures and residual stresses, the applicability of parts produced in an as-built state is limited. Therefore, often different post-processing treatments are necessary to obtain the desired stress state and properties.
For additively manufactured Inconel 718, the recently developed standard ASTM F3301 provides...

Through the development and improvement of nickel-based superalloys in the past century, they are well proved to show excellent performance at the elevated service temperature. The success of nickel-based superalloy systems attributes to both the well-tailored microstructures with the assistance of carefully doped alloying elements and the intently developed manufacturing processes. The...

Additive Manufacturing (AM) has clear advantages over conventional manufacturing methods, such as design freedom and manufacturability of hard-to-machine superalloys. A limiting factor, however, is the lack of understanding of microstructural and mechanical performance of AM materials, particularly for high value applications. Laser Powder Bed Fusion (LPBF), which is mainly used to fabricate...

Laser powder bed fusion provides valuable prospects for nickel-based superalloys that are used in many applications e.g. aerospace, automotive, chemical, and nuclear industries. However, the microstructure and mechanical properties of these materials are especially sensitive to the manufacturing conditions and post-treatment that are applied to relieve the internal stresses, as they are...

Laser powder bed fusion (L-PBF) is a versatile additive manufacturing process that can print geometrically complex metal parts for a variety of applications. However, poor control of the formation of defects such as pores and cracks during processing remains an obstacle to its widespread industrial adoption. In particular, many materials suffer from a high crack susceptibility during L-PBF,...

Components for high temperature gas turbine applications are increasingly complex with aerodynamic shapes and internal cooling systems. These components require materials that offer a combination of excellent high-temperature strength and oxidation resistance such as nickel-based superalloys with high gamma prime (g’) volume fractions. Additive manufacturing (AM) has gained increasing interest...

Additive manufacturing (AM) by laser powder bed fusion (LPBF) involves melting of layers of material onto a substrate, called a building platform. Due to cost or convenience considerations, building platform materials rarely match the LPBF material, especially for high temperature/strength materials. As it is often required that an additively manufactured component is...

This paper compares the fatigue properties of Inconel 625 elaborated by Laser Powder Bed Fusion (L-PBF) and Direct Energy Deposition (DED), at room and service temperatures. The two processes are based on metallic powder fused by laser, and the microstructures obtained are similar. A high chemical inhomogeneity is revealed by dendritic structures surrounded by the micro-segregation of heavy...

Ti-6Al-4V alloy is intensively used in the aerospace industry because of its high specific strength. However, the application of Laser Powder Bed Fusion (LPBF) Ti-6Al-4V alloy for structurally critical load-bearing components is limited. One of the main limiting factors affecting the structural integrity, are manufacturing defects. Additionally, the high cooling rates associated with LPBF...

Laser powder bed fusion (L-PBF) is a complex process in which many parameters intervene and interfere with each other and can have a significant impact on the melting behavior. Few of them: laser power, scan speed, hatch distance; are usually considered when developing the process while others such as powder size and gas atmosphere are most often neglected. The gas is an important parameter of...

Scope of this work is to overview the influence of a multiple step electrochemical surface treatment, heat treatment and print orientation on microstructure and mechanical properties of Ti 6Al 4V processed by laser powder bed fusion (L-PBF). Experiments were carried out from a first patch, after using virgin powder to avoid powder quality and morphology quality.
First tests include density...

As titanium-based alloys possess interesting specific mechanical properties, they are increasingly used in aerospace industry. Additive manufacturing is able to produce complex near net shape parts reducing the raw material quantity involved. This potential is of great interest for industrial applications. Among additive manufacturing processes, Selective Laser Melting (SLM) has proven to be...

With the development of additive manufacturing, new possibilities for the repair of damaged metal components are developing. Powder Laser Metal Deposition is one of these processes. In order to master and qualify this repair process, it must be characterized, controlled and optimized. This includes first of all the preparation of the part to be repaired by carrying out a pre-machining process...

The objective of this work is to improve the microstructure of the Ti-6Al-4V titanium alloy, especially during the Wire-Arc Additive Manufacturing (WAAM) using Tungsten Inert Gas (TIG) process. Indeed, WAAM processes may dramatically lower material consumption compared to conventional machining from a solid bloc. Although, the thermal gradient during solidification in additive manufacturing...

Abstract

Nowadays, the production of complex components becomes more and more difficult due to its cost. In order to reduce the latter, companies tend to use additive manufacturing (AM). This technique consists of building the component layer upon layer. Many technologies of additive manufacturing can be used such as Electron Beam Melting (EBM), which is a powder bed fusion process that...

Laser power bed fusion (L-PBF) of Ti-6Al-4V results in the formation of large directional prior-beta (β) columnar grains cooling down into brittle alpha/alpha prime (α/α’) phases with anisotropic properties and poor ductility. We have recently showed that it is possible to minimize microstructural anisotropy and control phase fractions by adding minor concentration of β stabilizer Fe...

Metal Additive manufacturing (AM) processes, such as Selective Laser Melting (SLM) or also called Laser Beam Powder Bed Fusion (LB-PBF), enable the fabrication of highly complex components from a 3-dimensional CAD model. Research is rapidly progressing in this field, thus ensuring application and promising achievements in the science and industry sector. Production of structures with...

This paper introduces a family of novel aluminium alloys, two ternary and two quaternary alloys. The alloys have been designed in a way to utilise the unique processing conditions provided by rapid solidification and re-melting which occurs during additive manufacturing using laser powder bed fusion process. These alloying design principle follows simple solidification calculations using...

A method to avoid hot cracking phenomena for aluminium alloys in Laser Beam Melting (LBM) has been developed, here focused on the 6061 alloy. 6061 is a precipitation-hardened aluminium alloy, containing magnesium and silicon as its major alloying elements. This alloy is particularly prone to hot cracking, in particular during LBM processing. The proposed solution to remove cracks is to induce...

Laser beam melting is a powder bed additive manufacturing process, allowing the fabrication of complex parts from 3D models. For each layer, powder is spread on building platform and particles are melted following the model by laser scanning. AlSi10Mg is a heat treatable alloy generally processed by casting, widely employed for transportation applications. This grade is one of the most used...

In the Horizon 2020 project MULTI-FUN, the manufacturing of fully integrated multi-functionalities of metal parts is the main focus. These functionalities include integrated electrical conductivity, embedded fibre-optical sensing or enhanced active/passive heat management. Several additive layer manufacturing technologies are under development to generate both the internal functional layers...

In this work, the authors present molybdenum alloys related to the TZM alloy, which were produced by Laser Powder Bed Fusion (LBPF). The results are put in relation to the alloying elements carbon, titanium and zirconium and their effects on the manufacturability, microstructure, and the material properties. The role of titanium and zirconium as getter elements for oxygen under the process...

Wire-based electron beam additive manufacturing (AM) has become an efficient and attractive directed energy deposition technique to produce mid-size near-net-shape parts. Due to the electron beam, the manufacturing takes place in a vacuum chamber, thus protecting the material from deleterious impurity pick-up. Important structural materials, such as titanium and aluminum, do not reflect the...

Titanium aluminides are presently used in aircraft engines and are also promising for the application in energy technology due to their low density, high stiffness and favorable high temperature properties. However, conventional manufacturing by casting or forging is relatively cost intensive, since the low ductility of these alloys requires special strategies, such as processing above the...

In comparison to their monolithic alternatives, composites of alumina and zirconia are particularly interesting for biomedical applications, thanks to their good mechanical and tribological properties and biocompatibility. The alumina toughened zirconia (ATZ, 80wt. % ZrO2 – 20wt.% Al2O3) was the main consideration as the starting material for this case due to its greater ageing (a.k.a. low...

Mechanical metamaterials with variable stiffness gained a lot of research interest, as they allow for structures with complex boundary and load conditions. Herein, we highlight the design, additive manufacturing and mechanical testing of a new kind of bending-dominated metamaterial. Advancing from well-established mechanical metamaterials concepts, the proposed geometry allows to vary the...

Laser powder bed fusion (L-PBF) is associated with the generation of spatters in the vicinity and from the melt pool, which are precursors for the formation of defects in the produced components. The main mechanisms for spatter formation were identified as direct melt pool spatters and entrained ones. Direct melt pool spatters are caused by important convection forces within the melt pool,...

The CoCr and Grade-23 Titanium alloys are two of the most used materials in dental and orthopaedic applications. However, “stress-shielding” (difference between bone and implant rigidity causing bone resorption and implant failure) issues and European change in the CMR (carcinogenic, mutagenic, and toxic to reproduction) classification of elements such as cobalt constitute challenges in the...

A major concern with laser based powder bed fusion (LB-PBF) is the limited number of qualified alloys. This is especially true for low-alloy steels, where the carbon content can adversely affect processability by increasing the number of defects (e.g. cracks). This study examines the effect of layer thickness (20, 40 and 60 µm) on the microstructure and processability of 4130 and 4140...

One of the factors limiting the use of additive manufacturing, particularly powder-bed processes, is their low productivity. An approach to increase the build rate of laser powder bed fusion (LPBF) without hardware modifications, such as the implementation of multiple laser sources, is to alter process parameters. In this study, equations for productivity are derived based on process...

The goal of this project was to assess the ability of the Additive Manufacturing technique for the manufacturing of space hardware and components with size larger than 0.5 meters.
The study shows how a large structure was built up by Plasma Metal Deposition (a plasma based DED process) while using Titanium grade 5 alloy, comparing both feedstock types of powder and wire. Initiated by ESA a...

Synthesis of multi-metal hybrid structures represents a serious scientific and technological challenge. In this contribution, liquid dispersed metal powder bed fusion was used to fabricate a multilayered structure based on alternating Inconel 625 alloy (IN625) and 316L stainless steel (316L) layers on a 316L base plate. Analytical techniques revealed sharp compositional and microstructural...

Among the few direct-write techniques for freestanding 3D-objects at the nanoscale, 3D-nanoprinting via Focused Electron Beam Induced Deposition (3D-FEBID) has made significant progress in recent years [1]. This additive manufacturing method, in which a gaseous precursor is locally immobilize upon irradiation with a focused electron beam, is capable of depositing complex 3D nanoarchitectures...

During the last ten years, additive manufacturing by using power bed fusion technology has become a very reliable technology to produce complex metallic parts. Layer by layer manufacturing allows the integration of a fiber bragg grating inside the parts during the fabrication. The latter opens a lot of possibilities for structural health monitoring. It has a critical impact for the monitoring...

3D Printing or additive manufacturing (AM) of ceramics and metals using lithography-based techniques is getting more and more attention in recent times. Using this route it is possible to combine the high precision and flexibility of lithographic AM processes with the exceptional material properties of ceramics and metals and thus, opening a completely new field for photopolymerization-based...

Shape memory alloys (SMA) are used in a wide range of applications where complex or customized geometries are required, as actors and sensors in aviation and aerospace or personalized medical devices. However, conventional shaping technologies are difficult to apply, mainly because of the high work hardening, strength, toughness and ductility of NiTi shape memory alloys. Hence, there is an...

Indirect additive manufacturing opens up new methodologies for producing innovative systems to unusual requests, like self-healing*. In the envisaged application as aeronautic, the matrix must contain sensors and/or actuators to detect cracks (sensors) and eliminate them (actuators). In this study, the material extrusion (MEX) technology was selected for shaping. This technology is...

In hybrid injection moulds, the mould cavity in which a polymer product is shaped consists of nonmetallic inserts produced by a rapid manufacturing method such as AM. A promising AM material currently investigated in our group is PA11 processed by MultiJet Fusion (MJF). The material choice is relevant as it largely influences injection parameters and final product properties, due to the...

Acrylonitrile-butadiene-styrene (ABS) is currently one of the most used polymeric materials in fused filament fabrication (FFF) for industrial applications, due to its good mechanical properties and good range of operating temperatures. However, materials printed via FFF present high anisotropy in the mechanical properties due to poor adhesion between the printed layers. This may lead to a...

Recent years have marked an increased interest in Additive Manufacturing (AM) processes and their applications. This manufacturing route presents advantages over conventional ones as it allows the production of geometrically complex parts in almost their net shape. This minimizes the required post-processing and thus raises opportunities of decreased material and time costs. However, it...

During an alloy Additive Manufacturing (AM) process, just after the melting of feedstock, the molten material undergoes melt-pool dynamics and rapidly solidifies (typically, within a few milliseconds). Then, for the remaining build time, it undergoes multiple heating-cooling cycles in the solid-state, i.e. Solid-State Thermal Cycling (SSTC) or intrinsic heat treatment, at varying temperature...

Mastering mechanical properties in metallic parts made by laser powder bed fusion (LPBF) process is of paramount importance. In this process, a deposited powder layer is melted by a laser and solidifies instantaneously when the laser moves away. During the solidification, the microstructure of the part is formed due both to epitaxial grain growth and nucleation process. As a consequence, the...

Due to the specific advantages of design flexibility, rapid prototyping, and the ability to produce complex geometries additive manufacturing (AM) industry is growing at a cumulative rate of 26% over the last 3 decades. However, the full potential of AM is yet to be realized as there are still many technical challenges owing to a lack of clear understanding of physical mechanisms. It is not...

The discovery of Bulk Metallic Glasses (BMGs) has stimulated great interest not only from the scientific community but also from the industry. Thanks to the random atomic structures and concomitant lack of dislocations, BMGs exhibit excellent combinations of properties compared with their crystalline counterparts, such as extremely high strength and hardness, remarkable wear, and corrosion...

Electron beam powder bed fusion (E-PBF) is an additive manufacturing process that allows for the production of individual metal parts with a high geometric freedom. This work adds another degree of freedom to the method by addressing the transition from processing a single alloy powder to a mixture of different powder compositions, which is termed as multi-material powder bed fusion.

For...

Metal additive manufacturing (MAM) has received a significant amount of attention from different industrial sectors such as medical, aerospace, automotive, energy, etc., mainly due to its uniqueness in manufacturing of customized assembled metallic components with complex geometries. On the other hand, this process entails a wide range of input process parameters that can affect the overall...

Modeling powder-based additive manufacturing technologies, specifically selective laser melting, is a great challenge due to the complex, interrelated phenomena that occur during the process, on multiscale space-time. This phenomena range from laser interaction with the powder particles and the melt, to melt pool formation, solidification, and microstructure evolution. Fully predictive...

Among promising approaches to accelerate the discovery of novel alloys and processing routes, Integrated Computational Materials Engineering (ICME) strongly relies on coupling different modeling techniques, relevant to different length/time scales and/or different physics. While a broad range of models have been developed, key challenges remain in the efficient coupling between these different...