Electron Beam Melting Research Articles

Titanium Additive Manufacturing with Powder Bed Fusion: A Bibliometric Perspective

Titanium additive manufacturing using powder bed fusion technologies has seen notable growth since 2015, particularly in high-performance sectors such as aerospace, biomedical, and automotive industries. This study focuses on key areas like metallic powder manipulation, laser optimization, and process control, with selective laser melting emerging as the dominant technique over electron beam melting. Advancements in powder materials and laser systems have been crucial to improving the efficiency and quality of the process, particularly in enhancing microstructure and porosity control. The bibliometric analysis reveals significant global interest, driven mainly by collaborations among institutions in Germany, the United States, and China, where further international cooperation is required to scale titanium additive manufacturing. However, additional research is essential to address challenges in scalability, sustainability, and post-processing, thus expanding the applications of PBF technology across industries. In conclusion, titanium processing via powder bed fusion is poised to make substantial contributions to the future of manufacturing, provided current challenges are addressed through innovation and enhanced global collaboration.

On the Peculiarities of Wire-Feed Electron Beam Additive Manufacturing (WEBAM) of Nickel Alloy–Copper Bimetal Nozzle Samples

In order to gain insight into the unique characteristics of manufacturing large-scale products with intricate geometries, experimental nozzle-shaped samples were created using wire-feed electron beam additive technology. Bimetal samples were fabricated from nickel-based alloy and copper. Two distinct approaches were employed, utilizing varying substrate thicknesses and differing fabrication parameters. The two approaches were the subject of analysis and comparison through the examination of the surface morphology of the samples using optical microscopy, scanning electron microscopy, and X-ray diffraction analysis. It has been demonstrated that the variation in heat flux distributions resulting from varying the substrate thicknesses gives rise to the development of disparate angles of grain boundary orientation relative to the substrate. Furthermore, it is demonstrated that suboptimal choice of the fabrication parameters results in large disparities in the crystallization times, both at the level of sample as a whole and within the same material volume. For example, for the sample manufacturing by Mode I, the macrostructure of the layers is distinguished by the presence of non-uniformity in their geometric dimensions and the presence of unmelted wire fragments. In order to characterize the experimental nozzle-shaped samples, microhardness was measured, uniaxial tensile tests were performed, and thermal diffusivity was determined. The microhardness profiles and the mechanical properties exhibit a higher degree of strength than those observed in pure copper samples and a lower degree of strength than those observed in Inconel 625 samples obtained through the same methodology. The thermal diffusivity values of the samples are sufficiently close to one another and align with the properties of the corresponding materials in their state after casting or rolling. The data discussed above indicate that Mode II yields the optimal mechanical properties of the sample due to the high cooling rate, which influences the structural and phase state of the resulting products. It was thus concluded that the experimental samples grown by Mode II on a thinner substrate exhibited the best formability.

Insights into Machining Techniques for Additively Manufactured Ti6Al4V Alloy: A Comprehensive Review

Investigation into the post-processing machinability of Ti6Al4V alloy is increasingly crucial in the manufacturing industry, particularly in the machining of additively manufactured (AM) Ti6Al4V alloy to ensure effective machining parameters. This review article summarizes various AM techniques and machining processes for Ti6Al4V alloy. It focuses on powder-based fusion AM techniques such as electron beam melting (EBM), selected laser melting (SLM), and direct metal deposition (DMD). The review addresses key aspects of machining Ti6Al4V alloy, including machining parameters, residual stress effects, hardness, microstructural changes, and surface defects introduced during the additive manufacturing (AM) process. Additionally, it covers the qualification process for machined components and the optimization of cutting parameters. It also examines the application of finite element analysis (FEA) in post-processing methods for Ti6Al4V alloy. The review reveals a scarcity of articles addressing the significance of post-processing methods and the qualification process for machined parts of Ti6Al4V alloy fabricated using such AM techniques. Consequently, this article focuses on the AM-based techniques for Ti6Al4V alloy parts to evaluate and understand the performance of the Johnson–Cook (J–C) model in predicting flow stress and cutting forces during machining of the alloy.

Electron Beam Additive Manufacturing of SS316L with a Stochastic Scan Strategy: Microstructure, Texture Evolution, and Mechanical Properties

This study examines the microstructure, crystallographic texture evolution, and mechanical properties of stainless steel 316L fabricated through electron beam melting using a stochastic scan strategy at a preheat temperature of 1123 K. X-ray diffraction confirmed the presence of a pure austenitic phase in the fabricated material. Equiaxed cellular structures were observed in the center of the melt pool regions and elongated cellular structures observed at the melt pool overlap regions. A finite element-based numerical model was employed to estimate the thermal gradients and solidification rates within the melt pool of an electron beam spot. Microstructural analysis indicated a generation of columnar grains from the bottom to the top of the build owing to high thermal gradients. A crystallographic texture investigation showed a generation of strong <110> fiber texture along the build direction of the material and reported that the stress distributions within the melt pool led to a strong crystallographic texture driven by the stress evolution observed from thermokinetic computational modelling of the electron beam-melting process. Mechanical properties were assessed using profilometry-based indentation plastometry, demonstrating strain hardening at a high temperature of 773 K.

Experimental investigation of the influence of process parameters on the mechanical properties of maraging steel produced by electron beam melting

Experimental investigation of the influence of process parameters on the mechanical properties of maraging steel produced by electron beam melting

Effect of grain size and orientation on magnetron sputtering yield of tantalum

The electron beam melting (EBM) technique was employed to prepare ultra-highly pure (99.999 wt%) Tantalum (Ta) cast ingot for application in chips. Subsequently, the Ta cast ingot were forged, rolled, and annealed with different durations to gain three different grain sizes (centimeter scale, 99.8 μm, and 36.7 μm). Sputtering experiments conducted under identical conditions revealed that the rolled target (36.7 μm) film deposition rate was increased by 60.6 % compared to the cast ingot target with a centimeter-scale grain size (columnar crystal). Ta targets with a fine grain size and homogeneous distribution demonstrate superior film deposition performance. The sputtering rate is directly related to the atomic packing density of grains. The (111)-oriented grains of BCC targets (Ta target) exhibit sputtering resistance, and the order of sputtering rate of Ta atoms was S(101) > S(001) > S(111).

A Systematic Review of the Contribution of Additive Manufacturing toward Orthopedic Applications.

Human bone holds an inherent capacity for repairing itself from trauma and damage, but concerning the severity of the defect, the choice of implant placement is a must. Additive manufacturing has become an elite option due to its various specifications such as patient-specific custom development of implants and its easy fabrication rather than the conventional methods used over the years. Additive manufacturing allows customization of the pore size, porosity, various mechanical properties, and complex structure design and formulation. Selective laser melting, powder bed fusion, electron beam melting, and fused deposition modeling are the various AM methods used extensively for implant fabrication. Metals, polymers, biocrystals, composites, and bio-HEA materials are used for implant fabrication for various applications. A wide variety of polymer implants are fabricated using additive manufacturing for nonload-bearing applications, and β-tricalcium phosphate, hydroxyapatite, bioactive glass, etc. are mainly used as ceramic materials in additive manufacturing due to the biological properties that could be imparted by the latter. For decades metals have played a major role in implant fabrication, and additive manufacturing of metals provides an easy approach to implant fabrication with augmented qualities. Various challenges and setbacks faced in the fabrication need postprocessing such as sintering, coating, surface polishing, etc. The emergence of bio-HEA materials, printing of shape memory implants, and five-dimensional printing are the trends of the era in additive manufacturing.

Construction of a mathematical model of turbulent heat and mass transfer processes for the case of electron beam melting of titanium alloy casts

This paper describes a mathematical model built for turbulent heat and mass transfer processes in the case of electron beam melting of titanium alloy ingots. The object of research is the conditions that ensure the quality of ingots. The model makes it possible to calculate the distribution of hydrodynamic flows in the liquid metal and temperature fields in the ingot, to determine the profile of the metal crystallization front, taking into account the interphase transition zones. The model solves the problem of finding the necessary melting regimes of ingots by calculation, in contrast to high-cost natural experiments. The thermal and hydrodynamic processes during the melting of a cylindrical ingot with a diameter of 110 mm of the newest titanium alloy Ti-6Al-7Nb for medical use were calculated and its melting parameters were determined. The small diameter of the ingot significantly facilitates its further machining. The geometry of the two-phase zone of the liquidus-solidus transition, which determines the crystallization front of the metal, was calculated. The position and geometry of this front greatly affects the quality of ingot formation and the concentration of the distribution of alloying elements and the homogeneity of the metal across its volume. A sufficiently flat crystallization front has been obtained, under which the given conditions are ensured. It was found that heat transfer in the liquid phase of the metal is mainly caused by heat and mass transfer due to its movement, and heat and mass transfer significantly depends on the power of the electron beam and its distribution on the surface of the bath. According to the calculated regimes, at the Institute of Electric Welding named after E. O. Paton, the National Academy of Sciences of Ukraine, high-quality ingots for the needs of the medical industry were smelted. The castings are used for the manufacture of light and ultra-strong endoprostheses and implants, which are chemically neutral and biologically and biomechanically compatible with the human body and do not cause rejection.

Life cycle assessment in additive manufacturing of copper alloys—comparison between laser and electron beam

AbstractAdditive manufacturing is becoming increasingly important for industrial production. In this context, directed energy deposition processes are in demand to achieve high deposition rates. In addition to the well-known laser-based processes, the electron beam has also reached industrial market maturity. The wire electron beam additive manufacturing offers advantages in the processing of copper materials, for example. In the literature, the higher energy efficiency and the resulting improvement in the carbon footprint of the electron beam are highlighted. However, there is a lack of practical studies with measurement data to quantify the potential of the technology. In this work, a comparative life cycle assessment between wire electron beam additive manufacturing (DED-EB) and laser powder additive manufacturing (DED-LB) is carried out. This involves determining the resources for manufacturing, producing a test component using both processes, and measuring the entire energy consumption. The environmental impact is then estimated using the factors global warming potential (GWP100), photochemical ozone creation potential (POCP), acidification potential (AP), and eutrophication potential (EP). It can be seen that wire electron beam additive manufacturing is characterized by a significantly lower energy requirement. In addition, the use of wire ensures greater resource efficiency, which leads to overall better life cycle assessment results.

Electrochemical characterization of TiO2 nanotubes formed on Ti6Al4V manufactured by PBF-EB or forging

AbstractThis study introduces the anisotropy effect of Ti6Al4V substrate obtained by electron beam melting (PBF-EB) on the anodizing process, revealing its capacity to induce anisotropic TiO2 nanotubes. Highly organized TiO2 nanotubes are formed on Ti6Al4V substrates produced through PBF-EB or forging, with the PBF-EB cross-orientation displaying superior nanotube growth due to enhanced catalytic activity. Morphological and electrochemical characterizations underscore the significant influence of substrate orientation and anodizing voltage on nanotube growth and corrosion resistance. PBF-EB-cross orientation at 30 V exhibits a thicker and more homogeneous nanotube layer, resulting in improved film resistance and substantially lower corrosion rates compared to forged substrates. The electrochemically calculated nanotube film thickness aligns with microscopic analyses, emphasizing the importance of a homogenous and resistive nanotube coating for effective corrosion control.

Specific Features of the Structure and Fracture of the Inconel 718 Alloy Prepared by the Method of Electron-Beam Melting

Specific Features of the Structure and Fracture of the Inconel 718 Alloy Prepared by the Method of Electron-Beam Melting

Research on energy utilization of electron beam melting for silicon purification

As a key material for solar photovoltaic power generation, the purity of silicon plays a crucial role in the photovoltaic conversion efficiency and performance. The electron beam melting (EBM), which is irreplaceable metallurgical methods, has been widely used for silicon purification. However, high energy consumption result in relatively high cost, which limits its widespread application in melting industry. This study was centered on the energy distribution that proposes a new approach to reducing energy consumption during EBM. The scanning form of electron beam is most important factor concerning energy consumption. Different scanning forms can affect the characteristics of molten pool which is closely correlated with the purification process. In this study, efficient and energy-saving preparation processes of EBM are being explored through the numerical model and experimental. The relationship of energy distribution form and purification efficiency is studied. The research results indicate that electron beam scanning under uniform distribution can achieve more uniform temperature and flow field distribution in the molten pool, which has a higher energy utilization rate during silicon purification by EBM. The mathematical model established in this study can effectively predict the energy consumption level under different melting parameters, providing important reference for the optimization and energy conservation of EBM process for other materials. In addition, evaporation characteristics of volatile impurity, migration of the second phase particles in the melt, controlling of melt pool characteristics and the crystal growth control all can be conducted based on this study.

Optimized Laser Surface Remelting of 3D-Printed Ti6Al4V Manufactured Through Electron Beam Melting

Optimized Laser Surface Remelting of 3D-Printed Ti6Al4V Manufactured Through Electron Beam Melting

INTERLAYER EFFECT ON DEFORMATION AND FRACTURE OF DENDRITIC STRUCTURE FORMED DURING WIRE-FEED ELECTRON-BEAM ADDITIVE MANUFACTURING OF AL-SI ALLOY

Interfaces and surfaces play an important role in tribology, mechanics and materials science, causing plastic strain localization and stress concentration of different spatial scales. The interfacial inhomogeneity is highly pronounced in 3D printed materials due to thermo-cycling and layer-by-layer building. In this paper, the inlayer and interlayer structure of a eutectic Al-Si alloy fabricated by wire-feed electron-beam additive manufacturing is investigated by optical and electron microscopy. Model structures inheriting the experimental morphology are created, and their deformation and fracture are simulated using ABACUS/Explicit, with the user-defined subroutines being developed to describe the constitutive behavior of aluminum dendrite, silicon and eutectic materials. A two-scale computational approach is implemented to study the influence of the interlayer formed in the heat-affected zone on the dendritic structure strength.

Microstructural evolution and dynamic recrystallization mechanisms of additively manufactured TiAl alloy with heterogeneous microstructure during hot compression

Microstructural evolution and dynamic recrystallization (DRX) mechanisms of a Ti−48Al−2Cr−2Nb (at.%) alloy prepared by selective electron beam melting (SEBM) during hot deformation at 1150 °C and 0.1 s−1 were investigated by hot compression tests, optical microscope (OM), scanning electron microscope (SEM), electron back-scattered diffraction (EBSD) and transmission electron microscope (TEM). The results show that the initial microstructure of the as-SEBMed alloy exhibits layers of coarse γ grains and fine γ+α2+(α2/γ) lamellar mixture grains alternately along the building direction. During the early stage of hot deformation, deformation twins tend to form within the coarse grains, facilitating subsequent deformation, and a small number of DRX grains appear in the fine-grained regions. With the increase of strain, extensive DRX grains are formed through different DRX mechanisms in both coarse and fine-grained regions, involving discontinuous dynamic recrystallization mechanism (DDRX) in the fine-grained regions and a coexistence of DDRX and continuous dynamic recrystallization (CDRX) in the coarse- grained regions.

Application of electron beam melting method for recycling of tantalum scrap

Application of electron beam melting method for recycling of tantalum scrap

Microstructure evolutions induced by electron beam melting of a sintered Cu-25Cr composite

Cu-Cr alloys are used as electrical contacts for medium voltage applications because of their desirable trade-off between electrical, thermal, and mechanical properties. However, few studies have investigated the microstructural evolutions caused by an electrical arc during an electrical breakdown. Herein, electron beam melting of a Cu-25Cr (wt.%) composite fabricated by solid-state sintering is used to mimic the thermal conditions of an electrical arc. The microstructure before and after melting was characterized using synchrotron x-ray computed microtomography and directly correlated with post-mortem electron microscopy observations. The melt pool consists of different zones: a fusion zone characterized by the complete melt of both Cu and Cr phases, and a partially melted zone where only the Cu phase is melted. Pores in the matrix or at the Cu/Cr interfaces are healed upon melting. Tracking large Cr-particles reveals significant spatial evolutions attributed to convective flows.

Effect of Aqueous Electrolyte Composition on Efficiency of Electrochemical Post-Processing of Additive Manufacturing Products from Ti-6Al-4V Alloy Obtained by Selective Electron Beam Melting

The influence of the anionic composition of an aqueous electrolyte on the efficiency of the electrochemical leveling of the initial microgeometry of samples obtained by the selective electron beam melting (SEBM) at the following mode parameters was studied: current density – 20 A/cm2, initial interelectrode gap – 0.3 mm, average speed of electrolyte pumping – 12 m/c. Aqueous solutions of sodium chloride, nitrate, perchlorate and bisalt electrolytes based on them were studied. It was that aqueous solutions of sodium perchlorate have the best microleveling properties among the studied working media, which provides the ability to reduce the parameters Ra and Rz from values of 35 and 180 μm, respectively, to values of 3.2 and 20 μm during electrolysis of 30 s in a direct-flow electrolyzer. It was established that the microgeometry leveling corresponds to the model of the secondary distribution of dissolution rates; two main factors were identified that significantly influenced on the result: polarization of the electrodes and a decrease in the oxidation state of metal ions passing into the solution during electrochemical machining in the vicinity of the depression in relation to the protrusion due to changes in the local conditions of electrolysis. Microetching along grain boundaries in the studied electrolytes was not detected at the accepted parameters of the electrolysis mode.

Comprehensive analysis of arc methods of 3D printing of metal products: assessment of the efficiency and prospects of using TIG as a heat source

In recent years, additive technologies have become increasingly important for the production of parts with complex geometries, enabling the rapid and efficient creation of objects with different shapes and configurations in industrial sectors such as medicine, aerospace and construction. The focus of the study was the analysis of arc processes for additive manufacturing, particularly through non-consumable electrode welding in an inert gas environment (TIG) and its applications as a heat source. Modern methods of 3D printing metal products, such as SLM (Selective Laser Melting), EBM (Electron Beam Melting), and LMD (Laser Metal Deposition), allow the production of parts with good quality indicators: accuracy, surface roughness, mechanical properties, and others. However, these methods are expensive due to the technological complexity of the equipment, and a weakness of these methods is their low productivity compared to arc methods. The results presented in this article show that the productivity of arc methods in additive manufacturing is several times higher than that of SLM, EBM, and LMD, and arc methods are more cost-effective due to lower equipment costs and reduced energy consumption. The article presents the schemes of arc methods of additive manufacturing. One of the promising directions in the development of hybrid technology, namely the use of the TIG heat source for sintering metal powders, offers an effective way to reduce the cost of additive manufacturing by replacing the laser as a heat source, while allowing the continued use of various types of metal powders, reinforcing materials, and metal-ceramic blends.

Microstructure and strength of a 3D-printed Ti–6Al–4V alloy subjected to high-pressure torsion

Currently, one of the effective 3D printing methods is wire-feed electron-beam additive manufacturing (EBAM), which allows producing large-sized commercial billets from Ti–6Al–4V titanium alloy. However, Ti–6Al–4V alloy produced by this method demonstrates reduced strength properties. It is known that it is possible to increase the strength properties of metallic materials by refining their grain structure by high-pressure torsion (HPT). This work is aimed at studying the influence of high-pressure torsion on the microstructure, and mechanical strength of a structural Ti–6Al–4V titanium alloy produced by the wire-feed electron-beam additive manufacturing method. The microstructure of a 3D-printed Ti–6Al–4V alloy in the initial state, and after high-pressure torsion, was studied using optical, scanning and transmission electron microscopy. An EBSD analysis of the material in its original state was carried out. The microhardness of the material in the initial and deformed states was measured. Using the dependence of the yield strength on microhardness, the estimated mechanical strength of the material after processing by the high-pressure torsion method was determined. The microstructural features of the 3D-printed Ti–6Al–4V alloy after high-pressure torsion, which provide increased strength of this material, are discussed. The research results demonstrate that 3D printing, using the electron-beam additive manufacturing method, allows producing a Ti–6Al–4V titanium alloy with a microstructure unusual for this material, which consists of columnar primary β-grains with a transverse size of 1–2mm, inside of which martensitic α'-Ti needles are located. Thin β-Ti layers with a thickness of about 200nm are observed between the α'-Ti needles. Further deformation treatment of the alloy, using the high-pressure torsion method, allowed forming an ultrafine-grained structure in its volume, presumably consisting of α-grains with an average size of (25±10)nm. High-pressure torsion of the 3D-printed alloy allowed achieving rather high microhardness values of (448±5)НV0.1, which, according to the HV=2.8–3σy ratio, corresponds to the estimated yield strength of approximately 1460MPa.