Wire-feed Electron Beam Additive Manufacturing Research Articles

Wire-Feed Electron Beam Additive Manufacturing: A Review

The work is devoted to a review of modern achievements in the field of wire-feed electron beam additive manufacturing. The features of structure formation in aluminum, copper, titanium, nickel-based alloys, and steels during 3D printing are shown. Aspects of directional solidification during the production of components from various metals and alloys are considered. The prospects for obtaining composite and functionally graded materials based on various metals and alloys using wire-feed electron beam additive manufacturing are determined. The regularities of the structure modification and hardening of additively manufactured materials by the method of friction stir processing were considered. The main purpose of the review is to present additive manufacturing methods, the main focus being on the wire-feed electron beam additive manufacturing of metal alloys.

A STUDY OF DEFORMATION AND FRACTURE OF THE EUTECTIC IN AN ADDITIVELY MANUFACTURED AL-SI COMPOSITE ALLOY

The structure of AlSi12 alloy fabricated by wire-feed electron beam additive manufacturing was studied experimentally. A numerical study was performed to examine the thermomechanical behavior and fracture of a eutectic fragment at the scale of several microns. Boundary dynamic problems were solved under plane strain conditions. The composite structure of the eutectic system consisting of an aluminum matrix and silicon particles was taken into account explicitly in the calculations. Isotropic models of the thermoelastic-plastic matrix and elastic-brittle particles were implemented in ABAQUS/Explicit. Strains in the composite were calculated both with and without allowance for residual stresses caused by cooling after fabrication. It was shown that after the cooling of the eutectic, silicon particles are compressed, and the aluminum matrix is under both bulk compressive and tensile as well as under pure shear stresses. It was found that residual stresses play a negative role at the stages of intense deformation of the composite. The fracture strain of the eutectic strongly depends on the yield stress of the matrix, while the ultimate fracture stress varies little. Favorable morphology of silicon particles was determined which prevents early fracture of the eutectic.

COMPARATIVE ANALYSIS OF WELD MICROSTRUCTURE IN TI-6AL-4V SAMPLES PRODUCED BY ROLLING AND WIRE-FEED ELECTRON BEAM ADDITIVE MANUFACTURING

The microstructure and phase composition of electron beam welded Ti-6Al-4V titanium alloy were studied by optical and scanning electron microscopy, backscattered electron diffraction, and X-ray diffraction analysis. Deep-penetration electron beam welds were made in single pass on rectangular Ti-6Al-4V samples obtained by rolling and wire-feed electron beam additive manufacturing. It was found that the weld width in 3D printed Ti-6Al-4V samples is greater than in the rolled material. The influence of the gas vapor channel on the size, shape and structure of primary β-grains formed in the fusion zone was shown. The variation of the penetration coefficient, volume fraction of the residual β phase, and residual stresses along the weld length was studied for Ti-6Al-4V samples obtained by both rolling and 3D printing.

Microstructure and Mechanical Properties of TC11 Titanium Alloy Fabricated by Wire-feed Electron Beam Additive Manufacturing

Microstructure and Mechanical Properties of TC11 Titanium Alloy Fabricated by Wire-feed Electron Beam Additive Manufacturing

Формирование биметаллического материала Ti–Al методом проволочного электронно-лучевого аддитивного производства

Currently, there is a request from aerospace and aircraft for the construction materials with sufficiently high mechanical strength, thermal creep, corrosion and oxidation resistance. The conventional alloys used for these purposes are too heavy. At the same time, alternative light materials such as Ti–Al-based alloys have many flaws, when they are produced by conventional methods. This work considers the possibility to produce the Ti–Al-based alloys by the method of a wire-feed electron-beam additive manufacturing (EBAM). We study the chemical and phase compositions, microstructure and microhardness of a bimetallic Ti–Al alloy, obtained by this method. It is found the formation of five characteristic regions between titanium and aluminum parts of the bimetallic billet. The mixing zone consists of TiAl and TiAl3 intermetallics, that is confirmed by the investigation of microstructure, chemical and phase compositions. According to XRD (X-ray diffraction) and EDS (energy-dispersive X-ray spectroscopy) analyses, it can be assumed that TiAl intermetallic prevails over TiAl3 one. The average microhardness of the mixing zone equals to 450 HV (≈4.4 GPa). This zone has developed dendritic microstructure, and even distribution of the phases without link to dendritic and inter-dendritic zones. The cracks appearing in this area are filled with the material of the upper layers, so the whole material is poreless and defect-free. Thus, the results of this work have shown a fundamental possibility to produce the intermetallic Ti–Al alloys with the use of the EBAM.

Structural Changes in Block-Shaped WEBAM’ed Ti6Al4V Samples after Friction Stir Processing

In this paper, the structure and mechanical properties of workpieces made of Ti6Al4V alloy in the shape of blocks manufactured by wire-feed electron beam additive manufacturing and processed by friction stir processing were investigated. Samples were cut from the upper and lower parts of the additive block and processed in the layer deposition direction using different tool loading forces. Studies have shown that the processing of such material forms a clearly defined thermomechanically affected zone represented by nanosized α-grains. In the stir zone, the material is characterized by a fine-dispersed structure with a content of α- and nanosized α″-phase plates. The material after processing demonstrates 24% higher values of the ultimate tensile strength as compared to the base metal in the as-built state.

Characterization of Microsegregation and Secondary Phase Precipitation in Nickel-Based Superalloy after Wire-Feed Electron Beam Additive Manufacturing

Characterization of Microsegregation and Secondary Phase Precipitation in Nickel-Based Superalloy after Wire-Feed Electron Beam Additive Manufacturing

Production of metal matrix composites based on aluminum-manganese bronze and nickel alloys by wire feed electron-beam additive manufacturing

Samples of composite materials based on BrAMts9-2 bronze with the introduction of the Udimet500 and Inconel625 nickel alloys were obtained by wire-feed electron-beam technology. The studies show that the structures of composites formed during printing, although fairly similar due to the same base of the alloys, have different features due to different combinations of alloying elements. The mechanical properties of the samples with the introduction of up to 15 % of the Udimet500 alloy are higher than those of the samples of the second material. With the introduction of 25 % of a nickel alloy, the strength is higher for the composite material samples with the introduction of the Inconel625 alloy. The microhardness of the samples with the introduction of 5 % of a nickel alloy is identical, the introduction of large volumes of a nickel alloy leads to the implementation of greater hardness in the samples with the introduction of the Inconel625 alloy due to the higher content of refractory materials. Relative elongation after rupture varies insignificantly for the samples of both types.

Microstructure and Phase Composition of VT1-0, VT6, and VT14 Titanium Alloys Produced by Wire-Feed Electron-Beam Additive Manufacturing

Microstructure and Phase Composition of VT1-0, VT6, and VT14 Titanium Alloys Produced by Wire-Feed Electron-Beam Additive Manufacturing

Micro-, Meso- and Macrostructural Design of Bulk Metallic and Polymetallic Materials by Wire-Feed Electron-Beam Additive Manufacturing

Abstract Additive manufacturing of metal materials is one of the most promising technologies in modern industry. A wide variety of current additive manufacturing techniques allow rapid prototyping and industrial production of different-sized products from various structural and functional materials. The structure and physical-mechanical properties of the metal products fabricated by electron-beam additive manufacturing (EBAM) within nonstationary metallurgy in a local molten pool often differ from those of the products fabricated by conventional metallurgy due to different crystallization mechanisms, sequence and completeness of phase transformations, and heterogeneous/homogeneous chemical composition of the resulting material. The possibility to control local metallurgical processes in the molten pool is the key advantage of the EBAM technology. It allows one to control the structure, composition, and properties of mono- and polymetallic, graded, composite and heat-resistant materials in order to obtain products with the desired chemical composition, macroscopic architecture, and microscopic structural parameters. As any new industrial technology, the EBAM method requires the development of scientifically based approaches to the choice of materials and production conditions. Here we provide an overview of the scientific approaches developed for electron-beam additive manufacturing of products from metals and alloys using wire or rods as a feedstock. The range of the studied materials includes additive materials based on copper, bronze, aluminum, nickel, titanium alloys, and different steels, as well as aluminum-based functionally graded materials and copper-based graded materials. The most important research findings are summarized.

Phase Formation, Microstructure, and Mechanical Properties of Ni-Cu Bimetallic Materials Produced by Electron Beam Additive Manufacturing

The paper presents the results of applying wire-feed electron beam additive manufacturing technology to produce bimetallic samples of CuCr1 copper alloy and Udimet 500 nickel-based superalloy. Different printing strategies were used to obtain samples with a defect-free structure and high mechanical properties in the transition zone, not inferior to the strength of copper alloy. Two types of samples were fabricated with a sharp and smooth CuCr1/Udimet 500 interface. The printing strategies of type I and II samples differed in the combination and arrangement of nickel and copper alloy layers. Structural studies in the transition zone revealed mechanical mixtures of initial copper and nickel alloy components and solid solutions based on nickel, copper, and chromium. Despite the presence of defects and structural heterogeneities in the experimental samples, the mechanical properties of the main components are at a high level, corresponding to the typical properties of copper and nickel alloys. The strength of the transition zone in type II samples is between the strength of Udimet 500 and CuCr1.

Obtaining of Bimetallic Product from Nickel Superalloy and Heat-Resistant Bronze by Wire-Feed Electron Beam Additive Manufacturing

Obtaining of Bimetallic Product from Nickel Superalloy and Heat-Resistant Bronze by Wire-Feed Electron Beam Additive Manufacturing

Microstructure and mechanical properties of Nb-alloyed austenitic CrNi steel fabricated by wire-feed electron beam additive manufacturing

We investigated the phase composition, microstructure, mechanical properties, and fracture mechanisms of Nb-alloyed austenitic stainless steel, produced by electron beam additive manufacturing (EBAM), after different regimes of the post-EBAM solid-solution treatments. As-build EBAM-produced steel has a predominantly austenitic structure, contains vermicular δ-ferrite (Vδ = 5–7%) and Nb-enriched precipitates (Laves phase Fe2Nb, FeNb and NbC). Niobium-alloying assists the stabilization of austenitic phase but does not suppress the columnar grain growth during EBAM-fabrication of austenitic stainless steels. Solid-solution treatments provide a change in morphology of δ-ferrite, a decrease in the ferrite volume fraction and the dissolution of intermetallic phases (Fe2Nb, FeNb), which all affect the tensile properties. Post-EBAM treatments contribute a decrease in the yield strength of the steel and improve the elongation-to-failure. All EBAM-produced specimens have good mechanical properties, which are comparable with those for steels produced by conventional methods. Irrespective of treatment regime, EBAM-fabricated specimens exhibit ductile transgranular fracture. For the EBAM-produced Nb-alloyed steel, the phase composition is described from the point of view solidification mode, and the effects of the precipitate hardening and solid-solution strengthening on the mechanical properties and fracture mechanisms were discussed.

Effect of Ion-Plasma Nitriding on Phase Composition and Tensile Properties of AISI 321-Type Stainless Steel Produced by Wire-Feed Electron-Beam Additive Manufacturing

We study the effect of ion-plasma surface nitriding on the phase composition, microstructure, surface microhardness, and tensile properties of the AISI 321-type stainless steel produced by wire-feed electron-beam additive manufacturing (EBAM). Ion-plasma nitriding at 550 °C for 12 h in N2/H2 gases provides the formation of a 10-μm thick surface layer with solid solution strengthening by nitrogen atoms (Fe-γN и Fe-αN) and dispersion hardening (γ’-Fe4N) with a fivefold increase in surface hardness up to ≈12 GPa. Surface ion-plasma nitriding of additively produced steel does not affect the anisotropy of mechanical properties, but rather increases the yield strength and ultimate tensile strength while maintaining high plasticity in the specimens. In specimens after ion-plasma nitriding, the fracture mechanism changes from initially ductile to a quasi-brittle fracture near the surface and ductile transgranular mode in the central parts of the specimens. The nitrided layer fractured in a transgranular brittle manner with the formation of quasi-cleavage facets and secondary cracks near the surface of the specimens. Brittle fracture of the compositional layer occurs due to the complex solid solution strengthening and particle hardening of austenite.

Regularities of Friction Stir Processing Hardening of Aluminum Alloy Products Made by Wire-Feed Electron Beam Additive Manufacturing

Friction stir processing of additive workpieces in the sample growth direction (the vertical direction) and the layer deposition direction (the horizontal one) was carried out. The hardening regularities of aluminum-silicon alloy A04130 and aluminum-magnesium alloy AA5056 manufactured by electron beam additive technology were studied. For each material, 1 to 4 subsequent tool passes were performed in both cases. It was found that the formation of the stir zone macro-structure does not significantly change with the processing direction relative to the layer deposition direction in additive manufacturing. The average grain size in the stir zone after the fourth pass for AA5056 alloy in the horizontal direction was 2.5 ± 0.8 μm, for the vertical one, 1.6 ± 0.5 μm. While for the alloy A04130, the grain size was 2.6 ± 1.0 μm and 1.8 ± 0.7 for the horizontal and vertical directions, respectively. The fine-grained metal of the stir zone for each alloy in different directions had higher microhardness values than the base metal. The tensile strength of the processed metal was significantly higher than that of the additively manufactured material of the corresponding alloy. The number of tool passes along the processing line is different for the two selected alloys. The second, third and fourth passes have the most significant effect on the mechanical properties of the aluminum-magnesium alloy.

Fabrication of Conically Shaped CuCr1 Chrome Bronze Products by Wire-Feed Electron Beam Additive Manufacturing

The structure and properties of conically shaped products made of CuCr1 chrome bronze obtained by wire-feed electron beam additive technology have been investigated. The studies show that the organization of the structure in the samples fully corresponds to the peculiarities of the printing process and heat removal from the samples. The structure is represented by large grains elongated in the direction of heat removal. Chromium in the samples is mainly localized in the form of particles located between the dendrite arms. Near the substrate, intense mixing of the bronze with the substrate material (steel 321) is observed. The mechanical properties of the conical and cylindrical sample parts material are at a fairly close level. The samples are characterized by low values of yield strength, low values of tensile strength and high plasticity. Near the substrate, the mechanical properties of the specimens increase.

Obtaining of Copper- and Nickel-Based Polymetallic Gradient Products by Wire-Feed Electron Beam Additive Manufacturing

The structure and mechanical properties of gradient transition zones of the copper-nickel system formed by additive electron beam technology have been investigated. Pure copper and nickel alloy Ni80Cr20 were used for printing. The data obtained testify to the complex and heterogeneous nature of structure formation when printing both by single-wire method and using double-wire controlled feeding of material into the melt bath. In the samples, the formation of defects of different scale from local inhomogeneities of the structure to pores and cracks is possible. The mechanical properties of the structural gradient zone are at a sufficiently high level and depend on the ratio of the system components.

Scientific approaches to micro-, mesoand macrostructural design of bulk metallic and polymetallic materials by wire-feed electron-beam additive manufacturing

Scientific approaches to micro-, mesoand macrostructural design of bulk metallic and polymetallic materials by wire-feed electron-beam additive manufacturing

Friction Stir Processing of Additively Manufactured Ti-6Al-4V Alloy: Structure Modification and Mechanical Properties

This work explores the possibility of using friction stir processing to harden the Ti-6Al-4V titanium alloy material produced by wire-feed electron beam additive manufacturing. For this purpose, thin-walled workpieces of titanium alloy with a height of 30 cm were printed and, after preparation, processed with an FSW-tool made of heat-resistant nickel-based superalloy ZhS6U according to four modes. Studies have shown that the material structure and properties are sensitive to changes in the tool loading force. In contrast, the additive material’s processing direction, relative to the columnar grain growth direction, has no effect. It is shown that increasing the axial load leads to forming a 𝛽-transformed structure and deteriorates the material strength. At the same time, compared to the additive material, the ultimate tensile strength increase during friction stir processing can achieve 34–69%.

A substrate material and thickness influence on the 3D-printing of Ti–6Al–4V components via wire-feed electron beam additive manufacturing

This work investigated the substrate effect on the additive manufacturing, also known as 3D printing, of Ti–6Al–4V alloy products by the wire-feed electron beam additive manufacturing. It was shown that the etching degree and the shape of the layer bands, known as heat-affected zones, are determined by the heat dissipation rate during 3D printing. Increasing the temperature gradient using a grade 2 Ti substrate decreases the α-phase plate thickness to 0.56 μm and provides the highest material strength and microhardness values among all tested samples. It was found that using substrates of technically pure Ti, the Al content in the bottom part of the wall decreases due to a mutual diffusion of substrate and sample materials. At the same time, at the printing on a Ti–Al–Mo–V alloy substrate, Mo does not penetrate the deposited material volume. Finally, the optimal substrate variants are determined to achieve the highest strength and elongation of the additively manufactured material at the selected fabrication parameters.