Wrought Products Research Articles

Electron Beam Powder Bed Fusion of ATI C103TM Refractory Alloy

The study investigated the use of electron beam powder bed fusion (EB-PBF) to fabricate niobium ATI C103™ alloy articles for microstructural characterization and mechanical testing. The feedstock powder was consolidated into low-porosity articles, and both powder and sample chemistry were monitored. Oxygen uptake in the powder was limited to less than the ASTM B655/B655M (2018) specification limits for 7 uses. Manipulating vacuum chamber pressure showed stable hafnium content but decreasing titanium content with decreasing chamber pressure attributed to evaporation. AM samples were evaluated in the post-processed, as-fabricated, annealed, and hot isostatic pressing (HIP) condition with a maximum yield strength of 287 MPa, UTS of 375 MPa for the HIP, and maximum elongation of 32 pct for the annealed specimens, respectively. Mechanical properties are similar to typical wrought products, with a notable increase in yield strength after post-processing by HIP. The fracture behavior was driven by porosity in the as-fabricated specimens and grain boundary fracture after HIP.

Applications of genetic algorithm in prediction of the best achievable combination of hardness and tensile strength for graphene reinforced magnesium alloy (AZ61) matrix composite

Due to lack of knowledge about role of process variables in the hot rolling of magnesium alloy composites, the most desirable wrought products of magnesium alloy-based composites could not be successfully produced till date. Moreover, use of wrought graphene reinforced magnesium alloy-based composite has emerged as a lucrative option for developing novel light alloy products in structural applications. The implicative need to obtain the best possible properties of the composite dictates to fix the optimized process variables in rolling operation. The present study envisages the development of data driven model that enables to derive desirable properties of the said composite; so, in order to secure the optimized subset of requirements (process parameters), a metaheuristic optimization tool is employed. We invoke the use of Genetic Algorithm (GA) optimizing tool in association with linear regression, so as to achieve the best combination of hardness and tensile strength of AZ-61-graphene nanoplate (GNP) composite.Modified magnesium AZ-61 alloy composites of varying GNP content (0, 1 and 2 wt.%) are produced by stir casting. The cast composites are homogenized at 450 °C for 12 h, followed by iced water quenching. The quenched materials are subjected to hot rolling and the process variables of hot rolling operation consist of rolling temperature, number of rolling passes as well as the initial stock thickness. The rolled materials are tested for hardness and tensile strength as the response variables. Instead of using artificial neural network to fix the objective function of GA, a mathematical model is developed by regression analysis; the derived equation is used as the objective function for multi-objective optimization task. The present paper explores the usefulness of implementing evolutionary algorithm (as in genetic algorithm) to correctly forecast the effect of rolling process variables onto the hardness and tensile strength of the stir cast AZ alloy-GNP nanocomposite.The experimental results show that the maximum achievable hardness value happens to be 106.6 VHN and is very close to that predicted by GA, ∼107.41VHN. Similarly, the maximum experimental tensile strength is found to be 266.82 MPa whereas, the corresponding GA predicted value is seen to be 253 MPa. A close fit can thus be noticed between the GA predicted and the experimentally obtained values. Barring a couple of exceptions, the difference between the experimental and GA predicted data lies within 1 % to 5 % (based on [Experimental value ∼ predicted value]/ [experimental value]). This entices to believe that the adopted muti-objective optimization strategy is quite useful in determining the optimum combination of rolling parameters that aids in achieving the most desirable property combination.

Tolerance of Al–Mg–Si Wrought Alloys for High Fe Contents: The Role of Effective Si

Aluminum scrap is often contaminated with steel parts, leading to accumulation of Fe in recycled Al alloys. Consequently, low limits for Fe in Al wrought alloys are difficult to meet by recycling without dilution with primary Al. Wrought alloys with a higher tolerance for Fe could help overcome this problem and improve the sustainability of Al wrought products. Here we study the effects of increasing the Fe content in EN AW-6060, 6005A, and 6082 from 0.2 to 0.7 wt pct. The microstructure and mechanical properties of the alloys after extrusion and artificial ageing are compared to the standard alloys. We found that 6082 is more tolerant to above-standard Fe contents than 6005A, which in turn is more tolerant than 6060: the strength of the 6082-based alloy with increased Fe content is comparable to that of standard 6082 and the elongation at break is increased. In contrast, the artificial ageing potential of the 6060-based alloy with more Fe is drastically reduced compared to 6060. This data and literature values show that the effective Si content is a good overall predictor of alloy strength. Effective Si is not bound in AlFeSi-type phases and is available for precipitation hardening. Additional effects of increased Fe levels are discussed.

Sustainability Study of a New Solid-State Aluminum Chips Recycling Process: A Life Cycle Assessment Approach

Nowadays, reducing greenhouse gas emissions in all human activities has become crucial. This article presents a life cycle assessment (LCA) investigation conducted to evaluate the environmental benefits of a newly developed solid-state recycling process for aluminum chips, involving two steps: direct rolling and accumulative roll bonding. A comparison was made between this process and two current industrial methods of recycling aluminum scraps to obtain wrought products, which involve melting, casting, and subsequent rolling. The LCA analysis considered a scenario where 50% of the total electric requirement was met by photovoltaic energy. The results of the study indicate that in all examined impact categories, direct rolling has a lower environmental footprint compared to both traditional recycling and twin-roll cast technology. These results suggest that this new solid-state recycling procedure has significant potential to replace environmentally harmful melting processes.

Study on joint characteristics in laser butt welding of AMed and wrought Ti6Al4V plates

Titanium alloy Ti6Al4V has been widely applied to medical, automotive, and aerospace industries due to its excellent properties such as high strength and excellent corrosion resistance. On the other hand, additive manufacturing (AM) technology can give the freedom of design of the products. In order to spread the AMed products, the joining of AMed and wrought products are required, and it is important to understand the joint characteristics. In this study, butt welding of Ti6Al4V plate was conducted by fiber laser in argon shielding, and the joint characteristics of laser weld wrought/wrought, AMed/AMed, and AMed/wrought Ti6Al4V plates were experimentally investigated. The AMed plate has higher tensile strength than wrought plate but the elongation of AMed plate is smaller, since AMed plate has α’ martensite due to rapid cooling during laser irradiation in AM process. Then, the laser weld joint of AMed/AMed plates has higher tensile strength, but smaller elongation than that of wrought/wrought plates. The weld joint of AMed/wrought plates shows good welding state, since small heat input leads to formation of small weld bead with higher hardness between wrought and AMed plates.

Helium bubble formation in additive manufactured L-PBF AlSi10Mg

Laser powder bed fusion additive manufacturing shows great promise for the nuclear industry due to unique and novel metallurgical phenomena and superior properties compared to cast or wrought products. The correlation between the unique microstructure of additively manufactured AlSi10Mg alloy, the radiation damage accumulation and its effect on the mechanical properties is examined. Laser powder bed fusion AlSi10Mg alloy was subjected to He+ ions implantation over an energy range that produced a 2 μm uniform layer within the bulk material to yield a local dose of 2000 appm at the depth of the material. It is shown that for each microstructural component the Helium bubble size, distribution and density depends on its stopping range. Furthermore, the overall increase in nanohardness in the irradiated region is in correlation with the measured defect density. In this unique microstructure interfaces play a diminished role at accumulating Helium bubbles compared to dislocations and dislocation structures indicating their relative sink strength.

Additive Manufacturing of Titanium-Based Materials Using Electron Beam Wire 3D Printing Approach: Peculiarities, Advantages, and Prospects

Potential of additive manufacturing technologies, namely, xBeam 3D Metal Printing for the fabrication of uniform Ti–6Al–4V (Ti-6-4, mas.%) material as well as layered titanium-based structures, with mechanical properties sufficient for wide practical application is demonstrated. The key distinctive features of this process are titanium alloy wire as a feedstock material and hollow conical electron beam for heating and melting of the wire. 3D printed with special ‘shift strategy’ Ti-6-4 alloy meets requirements to mechanical characteristics of corresponding conventional cast and wrought products, if microstructure features, material anisotropy and crystallographic texture are controlled with proper selection of processing parameters. Production of multilayered materials consisting of combined layers of different titanium materials, viz. commercially pure titanium (CP-Ti), Ti-6-4 and high-strength T110 alloys, as well as metal matrix composites (MMC) based on Ti-6-4 matrix reinforced by fine TiC particles is considered. Microstructural features and mechanical properties of all 3D printed materials are investigated. Terminal ballistic tests are performed with different ammunition. Described results show the promising potential of 3D printing technologies, xBeam 3D Metal Printing as an example, for manufacturing of titanium-based multilayered armour materials with reduced thickness and weight, and at the same time, sufficient protection characteristics.

Hot deformation behavior and microstructure of Ni-Cu rich Al-Si AA4032 alloy

The Al-Si alloy family is among the most widely used nonferrous alloys, in both cast and wrought products. The alloys have undergone a continuous progress toward improvement of various properties. The present research investigated the hot deformation behavior of AA4032 alloy, modified with addition of 3.5 %wt of Ni and 3%wt of Cu. The study was carried out using constitutive equations at the temperature range of 693–823 K (420–550 °C) alongside the strain rates of 0.001–1 s−1. The processing maps were determined by superimposing the instability maps on power dissipation maps. Moreover, the effect of extra copper and nickel on the microstructure and phase formation was studied via optical microscopy, SEM and TEM. The hot deformation activation energy of the Ni-Cu rich alloy is also calculated to be 338 KJ/mol (at ε = 0.1) which is notably higher than that of the self-diffusion of pure Al. It is found that the best hot working condition is the temperature range of 720–780 K with a strain rate of 0.001–0.03 s−1. The microstructure of the alloy at the calculated safe zone was uniform, while it showed cracking at the unsafe region of deformation parameters.

A review of the corrosion behavior of conventional and additively manufactured nickel-aluminum bronze (NAB) alloys: current status and future challenges.

The growing demand for materials with exceptional corrosion resistance and mechanical properties in the aerospace and ocean industries has led to increased research interest in versatile alloys like nickel-aluminum bronze (NAB). NABs exhibit excellent corrosion performance due to the formation of a protective, duplex corrosion product film on the surface, which is largely influenced by their complex microstructure. While NABs are typically produced as cast or wrought products, the emergence of additive manufacturing (AM) technologies has enabled 3D printing of near-net-shape NABs with intricate geometries. This paper provides a critical review of the corrosion properties, passivity, and microstructural characteristics of conventionally produced and AMed NAB alloys, as well as the fundamental mechanisms governing their corrosion behavior under varying conditions. Additionally, it highlights the current research gap and unprecedented challenges associated with the corrosion behavior of traditional and AMed NABs.

Forging of an age-hardenable Mg–Al–Ca–Mn–Zn alloy on industrial scale

Weight reduction plays an important role in transportation industries, directly impacting on fuel consumption and vehicle range. The use of multi-material mixes is common practice, allowing for an optimum application of specific material properties. Light metals, primarily aluminum alloys, are used in both, cast and wrought state, to good effect. On the other hand, magnesium alloys, which are still lighter by one third, are used in castings exclusively. While scientific research and development on Mg wrought alloys is progressing steadily, industrial implementation is still scarce. As a result, safety relevant and structural applications made from Mg wrought products are nearly nonexistent. To increase acceptance and facilitate industrial application for this interesting class of materials we investigated the forging process of an original-sized automotive control arm. To ease industrial access, the used age hardenable Mg–Al–Ca–Zn–Mn lean alloy, can be processed similarly to Al alloys, e.g. 6xxx series. This work describes the development sequence, starting with the analysis of the forming window, followed by laboratory forging trials and industrial sized part production, providing information on forming characteristics as well as possible difficulties.

Phase formation kinetics during heat treatments of Inconel 718 deposits based on cold metal transfer-based wire arc additive manufacturing

In this study, various heat treatments were conducted on Inconel 718 (IN718) products deposited by wire arc additive manufacturing (WAAM) to investigate the formation kinetics of phases at microstructural locations. The formation kinetics of the secondary phases precipitated by heat-treating of WAAM products differ from those of wrought or cast products because of the heat that accumulates during layer-by-layer deposition. Therefore, the secondary phases in the heat-treated WAAM products differ from those in conventional products according to the microstructural locations, e.g., the dendritic region, interdendritic region, and grain boundaries. To investigate such phase differences, a 100-layer IN718 wall was deposited using cold metal transfer (CMT)-based WAAM and then heat-treated under various conditions. In each heat-treated specimen, the δ, γ’, and γ” phases were identified by microstructural analyses. Based on the results, time–temperature–transformation diagrams were constructed for each microstructural location, which confirmed that the secondary phases were precipitated faster in the interdendritic region and at grain boundaries than those in the dendritic region. In addition, the applicability of single-aging, which can be used to satisfy the desired mechanical properties in less time with less processing, was evaluated by the hardness and tensile tests in the WAAM products.

Investigations of the quality of wrought semi-finished products from VT9 titanium alloy produced by electron beam melting

The Paton Welding Journal, 2022, №03. International Scientific-Technical and Production Journal «The Paton Welding Journal» «The Paton Welding Journal» has been published monthly since 2000 in English, ISSN 0957-798X. «The Paton Welding Journal» is a cover-to-cover English translation of the «Avtomaticheskaya Svarka» (Automatic Welding) journal. The «Avtomaticheskaya Svarka» journal has been published monthly since 1948 in Russian, ISSN 005-111X.

Study on development policy for new cryogenic structural material for superconducting magnet of fusion reactor

A fusion DEMO will require large-scale cryogenic structure including TF coil cases. Because of huge electromagnetic forces, extra thick plates and/or wrought products will be supplied. Since the midsection of the huge block is weaker than the block surface region, the design yield stress must be determined taking account of this lower strength part. To search the manufacturing process to improve the midsection strength, the crystal refinement strengthening and the precipitation strengthening are considered together with the carbon and nitrogen solid solution strengthening. XM-19 was focused based on the variation of the yield stress and the fracture toughness, a 100 mm thick block and a 30 mm thick plate were trial produced, and strength and the fracture toughness at the midsection were evaluated. This study will present the experimental data and discuss the development policy for a new cryogenic structural material for a fusion reactor.

Tailoring equiaxed β-grain structures in Ti-6Al-4V coaxial electron beam wire additive manufacturing

High-deposition-rate, directed-energy-deposition additive manufacturing (DED-AM) processes typically produce Ti-6Al-4-V (Ti64) components with coarse columnar β-grain structures that lead to undesirable mechanical anisotropy, as well as a fine heterogeneous lamellar transformation microstructure, which is very different to that seen for standard wrought products. This arises because of the intrinsic lack of constitutional undercooling at the solidification front, and the subsequent high cooling rates and rapid thermal cycling experienced by the deposited material. In this work, the more refined primary β-grain solidification structures and textures seen in components built with the novel coaxial electron beam wire DED AM (CEWAM) process have been characterised in detail, for the first time, with the aim of investigating the potential for this technology to directly replicate the β-annealed damage-tolerant microstructure used in large Ti64 aerospace forgings. Due to its different lower energy density solidification conditions, it has been confirmed, by electron backscatter diffraction (EBSD) analysis and β-grain reconstruction in three orthogonal cross-sections, that the CEWAM process changes the melt conditions to promote β-grain nucleation ahead of the solidification front, which can result in a highly refined, equiaxed, β-grain structure. However, the conditions for refinement were marginal and a mixed grain structure was commonly observed in thicker sections. Additionally, the subsequent grain-growth stability during β-annealing was investigated. It is shown that an equivalent microstructure can be achieved to that seen in a standard β-forged component, by grain structure homogenisation and slow cooling through the β transus, to promote α colony nucleation, allowing direct part substitution. This was made possible by the refined primary β-grain structure achieved during deposition with the CEWAM solidification conditions which, importantly, are also shown to lead to a weaker texture than in a typical forging.

Effect of Direct Powder Forging Process on the Mechanical Properties and Microstructural of Ti-6Al-4V ELI.

The study of powder metallurgy processing methods for titanium represents a promising avenue that can respond to a growing demand. This work reports the feasibility of direct powder forging (DPF) as a method to process large spherical Ti-6Al-4V powder into wrought products with noteworthy properties and physical characteristics. Direct powder forging is a thermomechanical process that imparts uniaxial loading to an enclosed and uncompacted powder to produce parts of various sizes and shapes. Stainless steel canisters were filled with prealloyed Ti-6Al-4V powder and consolidated through a multi-step open-die forging and rolling process into wrought DPF bars. After DPF, annealing was performed in the upper α+β phase. The results show that full consolidation was achieved and higher mechanical properties than the Ti-6Al-4V grade F-23 requirements in annealed conditions were obtained. The results also show that direct powder forging of spherical titanium powder could produce wrought mill products and exhibit some potential for further investigation for industrial applications.

Effect of thermo-mechanical treatment and strontium addition on workability and mechanical properties of Al Si Cu casting alloy

In this study, the potential application of Al-Si-Cu aluminum alloy (ALDC12), which is widely used in the high-pressure die-casting (HPDC) process, for fabricating a wrought product was evaluated. The effects of thermo-mechanical treatment and Sr addition on the microstructure, workability, and mechanical properties of the ALDC12 alloy were investigated in detail. The introduction of thermo-mechanical treatment significantly reduced the interconnectivity of the brittle eutectic Si phase formed during solidification and average grain size. Therefore, the uniformly distributed spherical Si particles and fine grain size considerably improved both the strength and ductility of the ALDC12 alloy. Furthermore, the addition of Sr effectively modified the eutectic Si phase in the casting process, which significantly reduced the occurrence of edge cracks in the subsequent rolling step and further improved the mechanical properties of the final sheets. Consequently, through microstructural control of the ALDC12 aluminum alloy by the thermo-mechanical treatment and Sr addition, it was possible to obtain suitable workability and significantly improved mechanical properties compared with those of cast products.

Effect of environmental relative humidity on hydrogen-induced mechanical degradation in an Al–Zn–Mg–Cu alloy

The influence of relative humidity (RH) on mechanical properties of a 7075 alloy, cold finished aluminum wrought product, was studied by slow strain rate technique in atmospheres with various RHs. Hydrogen was introduced into specimens from the testing environment during deformation and then thermal desorption spectrometry was utilized to determine the content of absorbed hydrogen. By increasing the RH in slow strain rate tensile tests, the ultimate tensile strength remained unchanged, the content of hydrogen increased, and the total tensile elongation reduced, revealing an increase in the hydrogen embrittlement sensitivity (HES). In RHs below 40%, the HES was insignificant. However, by increasing the RH, a sharp increase in HES was observed due to the formation of secondary cracks. The results firstly showed that even a normal humidity (40–60%) of the testing environment at room temperature can lead to a significant HES in a wrought aluminum alloy.

Age hardening heat treatment behavior of as-cast Mg–Zn–Al alloys

Magnesium alloys have generated renewed interest as a light alloys; replacing some conventional structural materials for weight reduction in applications like aerospace, automotive and electronics industries. In interior components and powertrains, cast alloys are widely used and represent more than 99% of magnesium alloys used today, whereas only a few wrought products are used. Mostly in automotive applications, Mg-engine block can noticeably reduce the weight and consequently its fuel consumption and environmental impact. Due to solid-state precipitates, these alloys are strong in nature and are produced by an age-hardening heat treatment process. In the present work the age hardening behavior of the as cast Mg–Zn–Al alloys (ZA85 alloy) in the composition of 8 wt. %Zn, 5 wt. %Al has been investigated. Through the differential thermal analysis (DTA) studies, it has been found out that dissolution temperature of ternary eutectic precipitates is present in the alloy. Based on the DTA results, the as cast samples have been solutionised at 360 °C temperature for different intervals of time. Solutionising time has been optimized from the enthalpy values of un-dissolved precipitates. The solution treated samples have been then aged at temperature of 180° C for different time intervals. From the peak hardness values, the ageing conditions have been optimized.

Structure formation and processability of the Al—Zn—Mg—Ca—Fe—Zr—Sc alloy at hot rolling and TIG welding

Process conditions are suggested for manufacturing wrought semi-finished products (2 and 1 mm sheets) from the Al-4.5%Zn-2.5%Mg-2.5%Ca-0.5%Fe-0.2%Zr-0.1%Sc experimental alloy including thermomechanical processing at t = 400450 °С and reduction ratios up to 98 %, as well as softening annealing of the sheet metal at t = 350400 °C for 1—2 hours. It was found that the as-cast structure consists of eutectic phases (Al, Zn)4Ca, Al10CaFe2 5 to 25 gm in size, and a Al2Mg5Zn5 nonequilibrium T-phase located along the boundaries of dendritic cells (Al). Zirconium and scandium form a solid solution with aluminum as a result of solidification. After hot rolling, the structure of 2 mm sheets consists of lineage-oriented discrete intermetallic particles and their conglomerates up to 40 gm in size in the (Al) matrix. The structure of 1 mm sheets features by greater fineness and structure uniformity. The fine structure of deformed semi-finished products was analyzed using transmission electron microscopy (TEM), and this analysis showed that nanoparticles in the Al3(Zr, Sc) phase of the L12 structural type are maximum 20 nm in cross-section. The following level of mechanical properties was achieved in wrought semi-finished products: ultimate strength σв ~ 310330 MPa, yield strength σ0,2 ~ 250280 MPa with relative elongation δ ~ 4.57.0 %. The possibility of TIG welding using standard AMg5 wire as a filler material was studied. It was shown that the new alloy demonstrated no tendency to form hot cracks. According to the results of X-ray tomography, the percentage of porosity in the weld was 1.27 vol.%. The prevalent pore diameter did not exceed 0.2 mm. In general, the resulting structural and qualitative parameters of weld joints contribute to obtaining a strength of 75 % of the strength index of the initial wrought semi-finished products (sheets) achieved by stabilizing annealing at t = 350 °С for 3 hours.

Structure and precipitation hardening response in a cast and wrought Al-Cu-Sn alloy

Experimental studies including microhardness and electrical conductivity measurements, transmission electron microscopy (TEM) together with atom probe tomography (APT) have been carried out for exploring the influence of tin (Sn) trace addition on the structure and precipitation hardening response in Al-Cu based alloy after either casting or cold or hot rolling. It is shown that the Sn trace addition refines the Al2Cu phase in an as-cast Al3.5Cu0.1Sn (wt.%) alloy. The alloy showed an increase by about 20% the peak hardness (~120 HV) for both cast and wrought products as well as significant reduction in the aging time to peak hardness (from 12 h to 2 h at 175 °C). According to the TEM and APT, the increased hardness is due to the formation of much finer θ′-phase precipitates with high number density.