Hybrid Deposition Research Articles

Analysis of thermal behavior and mass transport for manufacturing deep-small hole by ultra-high frequency induction-assisted laser wire deposition

Synchronous ultra-high frequency (UHF) induction-assisted laser deposition is an effective approach to tackle the extreme heat input and common defects that originate from laser direct deposition. The added auxiliary induction heat source can reduce the energy input of the laser heat source which guarantees the geometric integrity of the embedded tube and decreases temperature gradient. Meanwhile, the effective preheating of the induction heat source assures the metallurgical bonding among the substrate, deposited track and embedded tube. Experiments showed that the effective bonding can be formed among substrate-deposited track and deposited track-embedded tube under suitable combination parameters of the laser heat and induction heat. To gain insight into the hybrid deposition, a 3D numerical model coupled with multi-physical fields was established to explore the thermal process and flow behavior with assistance of induction heat. Results indicated that the electromagnetic force produced by induction coil promotes the flow velocity, which increases heat convection. Investigation on the induction heat parameter demonstrated that raising current intensity can accelerate the flow velocity from 0.07 m s-1 to 0.09 m s-1 while the maximum temperature of the molten pool declined from 2610 K to 2440 K owing to the reinforced heat convection. The experimental cross-section of the deposited tracks and the detected element distribution in transition areas are well tested against the numerical simulation results. The grain size in the top region of the deposited track is refined with increasing current intensity, which is experimentally and numerically verified by observed microstructure and G*R value. Meanwhile, the fabricated deposited track with average friction coefficient of 0.445 can be obtained when the laser and induction parameters are 1000 W and 400A, respectively.

Microstructure forming mechanism of inconel 625 alloy fabricated by laser/ultra-high (UHF) induction hybrid deposition method

To reveal the microstructure forming mechanism of laser/ultra-high frequency (UHF) induction deposition, this paper developed a microscopic phase-field (PF) model to numerically investigate dendrite growth during solidification. The macroscopic model of molten pool evolution is adopted to provide the solidification conditions for the microscopic PF model. The dendrite growth during laser deposition is simulated to evaluate the effect of UHF induction heat on the dendrite growth. Results show that because of the high temperature gradient and cooling rate, the PDAS of laser-UHF induction hybrid deposited layer is less than that of the laser deposited layer. The UHF induction heat also leads to a high flow velocity of the molten metal during laser-UHF induction hybrid deposition. The high flow velocity contributes to the decrease in PDAS by inhibiting the interdendritic enrichment of solute. During laser-UHF induction hybrid deposition, a higher solute gradient is present in the tip region of dendrite arm, leading to a faster dendrite growth rate. The UHF induction heat also increases the solute distribution coefficient during deposition, which further inhibits the element segregation. Under the action of UHF induction heat, a low interdendritic solute gradient and an evenly distributed solute can be obtained, thus helping increase interdendritic undercooling degrees and decreasing the PDAS. The simulated PDAS and solute distribution have good consistency with the experimental results. The spectral analysis of EDS line detection indicates that the laser-UHF induction hybrid deposited layer has a more refined microstructure and weaker element segregation than the laser deposited layer does.

Hybrid deposition of AlTiN/WN multilayer films with low compressive stress at low temperature

AlTiN/WN multilayer films with low compressive stress were deposited by arc evaporation and DC magnetron sputtering at a low temperature. The phase structure, morphologies, mechanical properties, wear behavior, and cutting performance of the AlTiN/WN multilayer films were evaluated. The results show that all the as-prepared AlTiN/WN multilayer films have fcc structure and exhibit (111) preferred orientation. The lowest value of −1.7 ± 0.3 GPa for compressive stress was obtained under low-temperature deposition. The film hardness increases as the temperature increases. High-temperature deposition provides higher energy to grow a dense film, which improves the film hardness. Increasing the WN layer thickness reduces the adhesion strength of the film. Compared with room temperature, the friction coefficients of the films against stainless steel reduce at high temperatures. This was attributed to lubricative oxides WOx formed on the wear surface at high temperatures. Dry cutting experiments were conducted and the longest service life of the coated tool reaches ∼3730 m. The worn flank surface shows that both adhesion and abrasive wear dominate the failure of the coated tools.

Synergistic effect of V and Ag diffusion favored the temperature-adaptive tribological behavior of VAlN/Ag multi-layer coating

Surface coating technology offers several benefits (excellent wear resistance, low coefficient of friction-COF, better corrosion durability etc.) for key components used in harsh aero-engines. However, the development of temperature-adaptive lubricant coating is still the crucial issue. In this study, VAlN/Ag multi-layer coatings with various thickness ratios were fabricated by a hybrid deposition system composing of DCMS and HiPIMS techniques. Results showed that all coatings presented Ag layers with growth twins, and fcc-VAlN layers with columnar structure. Increasing the temperature from 25 to 650 ℃ led to a decrease of COF from 0.47 to 0.22 in coatings, where the lowest COF and wear rate was particularly achieved at 0.08 and 4.3 × 10−5 mm3N−1m−1 under higher rotation speed, respectively. Based on the microstructural characterizations on wear track of coating and wear scar of counter ball, the synergistic diffusion of V and Ag elements at elevating temperature stimulated the in-situ formation of distinctive Al2O3/AgVO3-Ag3VO4/Ag microstructure, which encompass lubricant phases for lower COF and high wear resistance. The reason behind of this phenomena could be attributed to the easily broken of Ag-O bonds in lamellar silver vanadium oxides at high temperature, accompanying the remarkable lubrication of Ag on top layer.

Robotic additive manufacturing by laser metal deposition in the context of industry 4. 0

The integration of a KUKA robot with a Meltio Engine head to create a laser metal deposition by wire (LMD-wire) cell involves a meticulous installation and must be highly controlled to function with the required precision. To this end, the creation of a digital twin became essential to operate the cell and to generate data that enable its monitoring, through an artificial intelligence system that optimizes its performance and prevents equipment wear. The goal of this article is to present the research that the Industrial Automation Innovation Group at the University of Brasília has been developing. The procedures are detailed, such as the installation of the robot, the Meltio-KUKA integration, the elaboration of a planar slicer with Rhino3D-Grasshopper and the simulation process with KUKA.Sim. The simulations’ results confirmed the robustness of the system for planar deposition methods and demonstrated its versatility to adapt to non-planar, multiplanar and hybrid deposition methods. The integration of the LMD-wire cell will remain under evaluation until its complete installation, when it will be ready for the first deposition experiments.

External Hybrid Deposition: A Novel Method for Thermal Spraying of Thermally Sensitive Materials

External Hybrid Deposition: A Novel Method for Thermal Spraying of Thermally Sensitive Materials

Feasibility study and thermal process of producing deep-small holes by laser/ultra-high frequency induction hybrid deposition

In this study, a laser/ UHF induction hybrid deposition process with embedding tube for forming deep-small hole method is proposed. The laser and induction powers, as main and auxiliary heat source, are used to melt the metal wire and preheat the objects (the substrate, metal wire and embedded tube), respectively. The critical role of the preheating is to provide a high-temperature zone on the objects which guarantee the effective bonding among the deposited track, substrate and embedded tube. The embedded tube is pre-placed on the substrate outside induction coil and is not irradiated by laser beam, but is wrapped in the deposited track by dripped molten droplet. A numerical model coupled with temperature and electromagnetic fields is developed to investigate the thermal process during hybrid deposition. The thermal process with different combination states of laser and induction heating is numerically investigated to reveal the influence mechanism of the two heat sources on the penetration deposition of the deposited track and the size of molten metal in front of the deposition track. Results show that the laser heat mainly dominates the penetration depth of the deposited track and the size of the molten metal by increasing the temperature of the deposited metal. Criteria for characteristic temperature Tpeak2 is proposed based on the thermal process to avoid excessive temperature and possessing a large penetration depth of deposited track. The experiments demonstrate the process feasibility of the proposed deposited method and verify the reliability of the numerical model.

Efficient MAPbI3-based perovskite solar cells exceeding 21% efficiency via aging treatment

Recently, the demand for large-area and high-efficiency perovskite solar cells (PSCs) has increased, and a two-step process for high-efficiency large-area PSCs is actively being studied. However, the two-step process is still less efficient than the one-step antisolvent dripping process owing to the poor interdiffusion of organic components. In this study, a perovskite layer using a hybrid deposition method in which an excess of methylammonium iodide (MAI) solution is reacted with thermally evaporated PbI2 is reported. The perovskite film quality is improved by reacting unreacted residual PbI2 with excess MAI by applying daily electrical stress and aging for 60 days in a glovebox. The best PSC exhibits a PCE of 21.1 %, the highest reported power conversion efficiency among PSCs based on the two-step hybrid deposited MAPbI3 perovskite, with a large enhanced open-circuit voltage of 1.21 V and fill factor of 80.8 %. Moreover, using the solvent pre-heat treatment method, the reaction of unreacted PbI2 with MAI is accelerated, and the aging time of PSCs is shortened from 60 to 7 days, showing a PCE value of 20.7 %. Furthermore, we present a large-area PSC with a PCE of 19.4 %, indicating that the PCE can be improved through the hybrid deposition method.

Optical and Structural Properties of Europium-Doped Silicon Oxide Fabricated Using Integrated Sputtering and Chemical Vapour Deposition

Europium (Eu) doped silicon oxide (SiOx) thin films containing Eu concentrations of 0.2 to 6.4 at% were fabricated using a hybrid deposition system combining a magnetron sputtering gun serving as the doping source with electron cyclotron resonance plasma enhanced chemical vapour deposition (ECR-PECVD). The influence of annealing conditions on the structural and luminescence properties was thoroughly studied. The optical properties of the films were investigated by performing variable angle spectroscopic ellipsometry (VASE) and photoluminescence (PL) measurements. The Eu-related emission was found to be highly dependent on the deposition parameters and annealing conditions. Eu2+ and Eu3+ emissions, which are attributed to blue and red light emissions, respectively, were observed. The structural properties were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses, and the formation of nanoclusters was confirmed. At annealing temperatures of 900 °C and beyond, EuxSiyOz crystals were formed, and Eu ions were optically activated. As the light emissions of these thin films are in the blue and red wavelength range, they are promising candidates to be used as greenhouse covers and transparent solar cells.

Tribological behavior of MoS2/a-C:Si composite films in high-temperature air and vacuum environments

MoS2/a-C:Si composite films doped with different contents of carbon (C) and silicon (Si) were deposited using a hybrid deposition system consisting of a superimposed high-power impulse magnetron sputtering (HiPIMS)-direct current magnetron sputtering (DCMS) and a mid-frequency magnetron sputtering (MFMS). The content of C and Si elements in the films was controlled by changing the direct current (DC) of the graphite-silicon (C-Si) mosaic target. The effects of C and Si doping on the microstructure and mechanical properties of the films were investigated. In addition, the tribological behavior of the films in high-temperature air (up to 350 °C) and vacuum environments was evaluated in detail. The results suggested that MoS2/a-C:Si composite films exhibited excellent tribological properties in both high-temperature air and vacuum environments. MoS2/a-C:Si composite films doped with C and Si elements exhibited low coefficient of friction (COF) and wear rate (WR) at elevated temperatures due to the improved thermal stability. In particular, MoS2/a-C:Si composite film with 40.37 at% C displayed a low COF of 0.051 and a low WR of 1.47 × 10 −6 mm3/(N·m) at 350 °C in air. Moreover, MoS2/a-C:Si composite film also exhibited excellent tribological properties under vacuum conditions due to the precipitation of C on the wear track surface. The COF of MoS2/a-C:Si composite film with 40.37 at% C under vacuum conditions was as low as 0.018, and the WR of the film was as low as 1.99 × 10 −7 mm3/(N·m).

A Comparative Study on the Influence of Al2O3-ZnO ALD Nanolaminates on the Properties of CrCN PVD Sputtered Coatings with Distinctive Morphologies and Microstructures

Chromium carbonitride (CrCN) coatings present the desired characteristics for improving the mechanical properties and the corrosion resistance of marine components. The purpose of this work is to investigate the effect of carbon insertion, using CH4 gas flow as the carbon precursor in magnetron sputtering, on the mechanical and electrochemical properties of the CrN coating. Moreover, the influence of the Al2O3-ZnO nanolaminates sealing layers deposited by the atomic layer deposition (ALD) on the properties of distinctive CrCN sputtered coatings (dense and columnar) is investigated. Structural, morphological, and topographical analyses were performed using scanning electron microscopy, X-ray diffraction, and atomic force microscopy. The nanoindentation measurements determined the mechanical properties and the electrochemical behavior was evaluated in a saline solution. The results revealed new important insights in the field of duplex treatment based on hybrid deposition using magnetron sputtering and ALD techniques.

Evaluating the energy properties of the short-flow process based on the industrial metabolism: A case study on the metal 3D printing of hybrid deposition and micro rolling (HDMR)

The hybrid deposition and micro rolling (HDMR) is a new ultra-short process additive manufacturing (AM) technology, which combines in-situ rolling with additive manufacturing to greatly shorten and integrate the processing flow. In order to well understand the energy properties of the new technology, an industrial metabolic (IM) model is proposed with the complex processing parameters and equipment properties. The experimental test verifies that the deviation of specific energy consumption (SEC) computed by the IM model is 4.43% in the short-flow process of HDMR. Further study compares the energy properties of HDMR process with the conventional manufacturing (CM) processes by taking a cross-shaping part made of Ti-6Al-4V as an example. The results using the IM model show that the energy consumption of HDMR is reduced by 46.83% comparing with CM, by shortening the processing flow greatly. The short flow process of HDMR extremely reduces the melting heat and deformation energy in the deposition and rolling processes, compared with the significant energy consumption in the conventional processes of casting and forging. Meanwhile, the specific energy loss (SEL, energy loss per kilogram of materials) in HDMR is approximately 2 times lower than that of CM, which implies that HDMR has obvious advantages in the energy utilization with a shorter processing cycle. The study implies that industrial metabolism of the short-flow process like HDMR is more effective and appropriate to processing the titanium alloy with higher efficiency.

Strengthening and toughening of additively manufactured Ti-6Al-4V alloy by hybrid deposition and synchronous micro-rolling

Strengthening and toughening of additively manufactured Ti-6Al-4V alloy by hybrid deposition and synchronous micro-rolling

Depositional and diagenetic conditions during early South Atlantic opening: Evidence from the upper Aptian Oiteirinhos Member, Muribeca Formation, Sergipe-Alagoas Basin, NE Brazil

The Muribeca Formation from the Sergipe-Alagoas Basin, northeastern Brazil, records the transition from continental to marine conditions during the initial South Atlantic opening. The formation is constituted by the basal coarse clastics of the Carmópolis Member, covered by the Ibura Member evaporites, and the Oiteirinhos Member. The Oiteirinhos Member presents a wide lithological variation, including siliciclastic, carbonate, and hybrid deposits. Considering the scientific importance of understanding the conditions during this key time in South Atlantic evolution, very few sedimentological studies were performed on the Oiteirinhos Member. This article presents a petrological characterization, integrated with sedimentological data from five onshore wells. The studied rocks include siliciclastic sandstones, siliciclastic-carbonate hybrid arenites, marls, microbialites, calcarenites, and calcilutites. The composition of the sandstones is rich in low-grade metasedimentary fragments from the erosion of upper Proterozoic supracrustal orogenic terrains. Intrabasinal carbonate constituents include ooids, peloids, oncoids, intraclasts, bioclasts of ostracodes, benthic foraminifers, and echinoderms. Carbonate microbialites occur associated with laminated organic mud deposits, commonly rich in carbonaceous and phosphate fragments. The main diagenetic process occurred near-surface, under the influence of an evaporitic, dry climate under continental and marine conditions. The depositional and diagenetic aspects reveal progressively less evaporitic conditions during the deposition of the Oiteirinhos Member, with anhydrite followed by siliciclastic and hybrid deposits and finally by marine carbonates.

Thermal process and flow behavior during laser/ultra-high frequency (UHF) induction hybrid deposition

In this study, ultra-high frequency (UHF) induction heat was combined with laser deposition, which is referred to as laser–UHF induction hybrid deposition. On the one hand, this method takes the conventional laser induction hybrid deposition as reference, which uses the heat effect of UHF induction heat to optimize the residual stress of the deposited layer. On the other, this method utilizes the strong Lorentz force generated by the UHF induction heat to accelerate the flow velocity of the molten metal, which will be beneficial for microstructure refinement. Given that the thermal process and flow behavior during deposition are critical factors for the microstructure, a numerical model coupled with temperature field, electromagnetic field, flow field, and mass transfer field was developed to investigate the thermal process and flow behavior during laser–UHF induction hybrid deposition. Results showed that the UHF induction heat in laser-UHF induction hybrid deposition has pre-heating and slow-cooling effects on the deposited layer compared with laser deposition. The Lorentz force generated by UHF induction heat enhanced the flow velocity and the heat convection in molten pool. Research on the UHF induction heat parameters indicates that increasing the current frequency or current density can strengthen the slow-cooling effect of the UHF induction heat, and the flow velocity of the molten metal can be increased by 12.1% and 24.6%. Moreover, the maximum temperature in the molten pool decreased with increasing current frequency or current density because of the enhanced heat convection. Laser–UHF induction hybrid deposition experiment was also conducted, and the detected elemental content of the deposited layer and temperature showed good consistency with the simulated results. The grain size in the microstructure of the experimental laser–UHF induction hybrid deposited layer can be refined to approximately 3.358 μm at high current density conditions because of the enhanced fluid flow and heat convection in molten pool. This work provides an effective tool for predicting the thermal process and flow behavior during laser–UHF induction hybrid deposition, which will be an essential reference for evaluating microstructure quality.

Microstructure, Wear Resistance and Corrosion Performance of Inconel 625 Layer Fabricated by Laser/Ultra-High Frequency (UHF) Induction Hybrid Deposition

In order to avoid microstructure degradation caused by low frequency induction heat in laser-induction hybrid deposition, this paper proposes a laser/ultra-high frequency (UHF) induction hybrid deposition method. Microstructure observation is carried out to reveal the effect of UHF induction heat on the microstructure of the deposited layer. Results indicate that the laser-UHF induction hybrid deposited layer, under a current density of 1.14 × 108 A/m2, exhibits a finer microstructure and fewer Laves phases than that of the laser deposited layer. As the current density increases from 1.01 × 108 A/m2 to 1.14 × 108 A/m2, the microstructure of the laser-UHF induction hybrid deposited layer is significantly refined; however, as the current density further increases, the microstructure is only slightly further refined, since the enhanced thermal effect, along with the increasing current density, may help grain growth. Wear test demonstrates that the laser-UHF induction hybrid deposited layer obtained with a current density of 1.40 × 108 A/m2 has the lowest average friction coefficient of 0.375 and the lowest wear rate of 15.53 × 10−5 mm3/N·m, indicating a better wear resistance. Corrosion resistance is also evaluated by electrochemical corrosion test. Results indicate that the addition of UHF induction heat improves the corrosion resistance of the deposited layer. Owing to the high ohm resistance of the passive film, the deposited layer fabricated with a current density of 1.01 × 108 A/m2 exhibits the best corrosion resistance. Based on the analysis of wear and corrosion performance, the current density of 1.40 × 108 A/m2 is an optimal parameter for a laser-UHF induction hybrid deposited Inconel 625 layer.

Photovoltaics literature survey (no. 182)

Photovoltaics literature survey (no. 182)

Numerical and Experimental Investigations of Cold-Sprayed Basalt Fiber-Reinforced Metal Matrix Composite Coating.

The aluminum-basalt fiber composite coating was prepared for the first time with basalt fiber as the spraying material by cold-spraying technology. Hybrid deposition behavior was studied by numerical simulation based on Fluent and ABAQUS. The microstructure of the composite coating was observed on the as-sprayed, cross-sectional, and fracture surfaces by SEM, focusing on the deposited morphology of the reinforcing phase basalt fibers in the coating, the distribution of basalt fibers, and the interaction between basalt fibers and metallic aluminum. The results show that there are four main morphologies of the basalt fiber-reinforced phase, i.e., transverse cracking, brittle fracture, deformation, and bending in the coating. At the same time, there are two modes of contact between aluminum and basalt fibers. Firstly, the thermally softened aluminum envelops the basalt fibers, forming a seamless connection. Secondly, the aluminum that has not undergone the softening effect creates a closed space, with the basalt fibers securely trapped within it. Moreover, the Rockwell hardness test and the friction-wear test were conducted on Al-basalt fiber composite coating, and the results showed that the composite coating has high wear resistance and high hardness.

Hybrid Erosion And Deposition Metaheuristic University Teaching Timetabling Framework

The research developed a Hybrid Erosion And Deposition Metaheuristic University Teaching Timetabling Algorithm (HEADMUTTA). The hybrid erosion and deposition metaheuristic university teaching timetabling algorithm constructs a university teaching timetable with very few iterations. The Hybrid Erosion And Deposition (HEAD) metaheuristic university teaching timetabling algorithm adopts its behaviour from the HEAD metaheuristic with some concepts adapted from Tabu Search, Simulated Annealing, and Ant Colony metaheuristics. The HEADMUTTA constructs a draft university teaching timetable and further improves it by searching for the best feasible solution that satisfies the predetermined soft and hard rules or constraints. The research also proposed a Hybrid Erosion and Deposition Metaheuristic University Teaching Timetabling framework for implementation. The results indicate that the use of hybrid metaheuristics to solve university teaching timetabling problems improves the quality of the produced university teaching timetables. The HEAD metaheuristic algorithm has a unique feature that allows it to further improve the draft university teaching timetable. Further improvements in the framework may reduce the complexity of NP-hard combinatorial teaching timetabling problems.

Superhydrophobic and oleophobic microtextured aluminum surface with long durability under corrosive environment

Superhydrophobic (SHP) and oleophobic aluminum surfaces have been prepared through the combination of a scalable chemical microtexturing process and surface functionalization with long-chained polyfluoroalkyl moieties. The effect of an anodic layer on the microtextured surface has been assessed considering surface morphology, superhydrophobicity, surface mechanical properties and corrosion protection enhancement. The surface functionalization with polyfluoroalkyl moieties has been tackled in two different ways: (i) grafting of the polyfluoroalkyl moieties and (ii) deposition of a thin hybrid coating with low content of polyfluoroalkyl-containing compound. Aluminum surfaces showing high durability in salt spray environments, which maintain SHP and oleophobic properties at least up to 2016 h have been attained. Applications for this kind of surfaces range from easy-to-clean surfaces to anti-icing or anti-condensation functionalities that could be of interest for several sectors.