This study investigates the impact of printing orientation on the mechanical properties and surface characteristics of parts produced using VeroWhitePlus RGD835 polymer material in a layer-based Polymer Jetting Technology process. Tensile, hardness, and surface roughness tests were conducted to evaluate the influence of different printing orientations on the properties of the printed samples. The results show that printing orientation significantly affects both the mechanical strength and surface roughness of the parts. Specifically, samples printed in the XZ, YZ, and vertical orientations exhibited 20–30% higher tensile strength and 15–25% greater hardness compared to those printed in XY and other orientations. Surface roughness values varied by up to 10 µm across orientations but did not directly correlate with tensile strength and hardness, suggesting a complex interaction between orientation, layer bonding, and material properties. This anisotropic behavior is attributed to the non-uniform absorption of light energy during the jetting process, which causes varying layer bonding and material density across different regions of the printed parts. Additionally, areas with higher energy absorption, such as the edges of layers, exhibited smoother surfaces and enhanced mechanical properties, while regions with lower energy absorption showed rougher surfaces and reduced strength. Fracture surface analysis revealed brittle fracture characteristics with localized pressures and voids between layers, weakening the material’s ability to withstand deformation. These findings provide valuable insights into the optimization of Polymer Jetting Technology processes, particularly in selecting printing orientations and adjusting process parameters such as light exposure intensity, to improve mechanical performance and surface quality.

This study explores the joining of AA6061-T6 aluminium alloy and AZ31B magnesium alloy using the Cold Metal Transfer (CMT) process with ER4043 aluminium filler wire. The influence of wire feed speed (WFS), welding speed (WS), and arc length correction (ALC) on weld bead geometry, microstructure, and mechanical properties of Al/Mg joints was investigated. The results indicate that WFS, WS, and ALC significantly affect weld characteristics. Increasing WFS leads to higher heat input, improving reinforcement height, penetration, and bead width. At 4700 mm/min WFS, optimal reinforcement height was achieved, while 5000 mm/min further enhanced penetration and bead width. Higher WS reduced heat input, resulting in narrower bead width, shallower penetration, and lower reinforcement height. ALC influenced arc behaviour, with 10% ALC minimising the weld metal area and 15% significantly increasing it. Microstructural analysis identified MgO, Mg solid solution, Mg2Al3, and Mg17Al12 at different joint regions. The optimized parameters (4700 mm/min WFS, 280 mm/min WS, 10% ALC) yielded the highest tensile strength of 34 MPa and hardness of 120 HV. Fracture occurred mainly at the Mg/weld interface and near the fusion line. This study underscores the importance of welding parameters in enhancing the mechanical properties of Al/Mg joints and provides insights for optimising aluminium-magnesium welding.Cette étude explore l'assemblage de l'alliage d'aluminium (Al) AA6061-T6 et de l'alliage de magnésium (Mg) AZ31B à l'aide du procédé de transfert de métal à froid (CMT) avec un fil d'apport en aluminium ER4043. La recherche examine l'influence des paramètres clés du procédé – vitesse d'alimentation du fil (WFS), vitesse de soudage (WS) et correction de la longueur de l'arc (ALC) – sur la géométrie du cordon de soudure, la microstructure et les propriétés mécaniques des joints Al/Mg dissemblables. Les résultats indiquent que l'interaction de WFS, WS et ALC influence significativement les caractéristiques de la soudure. Une augmentation de WFS conduit à un apport de chaleur plus élevé, résultant en une plus grande hauteur de renforcement, une profondeur de pénétration améliorée et un cordon plus large. À une WFS de 4700mm/min, on a observé une hauteur du renforcement optimale, avec de nouvelles augmentations de WFS de 5000mm/min améliorant la pénétration et la largeur du cordon. Inversement, une WS plus élevée réduit l'apport de chaleur, conduisant à un cordon plus étroit, une pénétration moins profonde et une hauteur de renforcement plus faible. Le paramètre ALC influence davantage le comportement de l'arc, avec un ALC de 10% minimisant la zone de métal fondu (WM) et un ALC plus élevé (par exemple, 15%) l'augmente significativement. L'analyse microstructurale a révélé la présence de différentes phases à des positions variées dans le joint. Au niveau du substrat de Mg, on a observé du MgO et une solution solide de Mg. Près de l'interface du métal fondu, on a également trouvé du MgO et une solution solide de Mg. L'interface a montré la formation de phases de Mg2Al3 et de Mg17Al12, tandis que près de l'interface du métal fondu, on a détecté du Mg2Si, du MgO et une solution solide d'Al. Dans le métal fondu, les phases prédominantes consistaient de Mg2Al3 et de solution solide d'Al. Les joints fabriqués a l'aide des paramètres optimisés – 4700mm/min WFS, 280mm/min WS et 10% ALC – exhibaient la résistance à la traction de 34MPa et la dureté de 120 HV les plus élevées. L'analyse des fractures a montré que la rupture se produisait principalement à l'interface Mg/soudure et près de la ligne de fusion du côté du Mg. Cette étude souligne le rôle critique des paramètres de soudage dans l'amélioration des propriétés mécaniques des joints dissemblables d'Al/Mg et offre un aperçu des développements futurs du soudage des alliages aluminium-magnésium.

Property mapping, an indentation technique, was employed to investigate the nano-mechanical behaviour of austenite, ferrite, and interphase regions in duplex stainless steel (DSS). The influence of furnace cooling and water quenching heat treatment processes on the deformation behaviour of individual phase regions was quantitatively assessed in both the transverse and longitudinal sections of DSS samples. Property evaluation across these regions was conducted through load-displacement curves and associated material parameters such as empirical property ratios, elastic-plastic indentation work values, and other mechanical properties. This study reveals the heterogeneous and anisotropic nature of the mechanical behaviour of DSS phase regions across the sections, which can assist in improving structural design(s).

Wire arc additive manufacturing (WAAM) using the cold metal transfer (CMT) process has emerged as a transformative method for producing near-net-shape metal components with tailored microstructures and enhanced mechanical performance. This study investigates the wear characteristics of components fabricated using CMT-based WAAM with ER70S-6 low-carbon steel (LCS) and 316LSi stainless steel (SS), focusing on their potential for abrasive and erosive wear applications. Microstructural analysis, including phase transformations and grain morphology, was performed in both the deposition (X) and building (Y) directions. Wear testing was conducted on a pin-on-disc machine under varying loads (1.5–3.5 kg) and sliding speeds (150–450 rpm) to evaluate wear rates, coefficients of friction (COF), and wear track morphology. The microstructure of the WAAMed LCS component is characterized by lamellar structures of ferrite and pearlite, with variations observed along the X- and Y-directions. The X-direction shows ferrite structures including polygonal ferrite and Widmanstätten ferrite (?WD), while the Y-direction exhibits acicular ferrite (?ac) and bainite (B) phases. The WAAMed 316LSi SS shows austenitic structures with residual ferrite, exhibiting lathy ferrite morphology in the X-direction and vermicular ferrite in the Y-direction. At the highest load and speed, the wear rate of 316LSi SS was reduced by 83.51% compared to LCS, with wear rates ranging from 0.74×103 to 1.98×103 g/m for 316LSi SS, and from 1.64×104 to 2.65×104 g/m for LCS. The COF for 316LSi SS remained within 0.34–0.45, significantly lower than the 0.53–0.57 observed for LCS. SEM analysis of worn surfaces identified abrasive, adhesive, and delamination wear as predominant mechanisms for LCS, whereas 316LSi SS showed minimal material loss due to its higher hardness (193–227 HV0.5 vs. 160–187 HV0.5 for LCS) and stable microstructure. These results establish WAAM-fabricated 316LSi SS as a promising material for wear-critical applications, providing a foundation for optimizing processing parameters and material properties.

This study investigates the effect of forging pressure on the microstructural evolution, mechanical properties, and fracture behaviour of rotary friction welded (RFW) low-alloy steel (LAS) joints. Three forging pressures—0.76, 0.84, and 0.91MPa/s—were applied to evaluate their influence on hardness, tensile strength, and ductility. Microstructural analysis revealed that at 0.84MPa/s, significant grain refinement occurred in the heat-affected zone, promoting superior mechanical properties. The ultimate tensile strength increased from 473MPa at 0.76MPa/s to 488MPa at 0.84MPa/s, before slightly decreasing to 482MPa at 0.91MPa/s due to grain coarsening. A maximum elongation of 40.01% was achieved at 0.84MPa/s, representing a 27.05% improvement compared to 0.76MPa/s. Hardness variations followed a similar trend, with peak values observed at intermediate forging pressure. Fractographic analysis confirmed a ductile fracture mode at 0.84MPa/s, characterised by deep equiaxed dimples, while coarser fracture features were noted at higher pressures. These results demonstrate that an optimal forging pressure enhances strength–ductility synergy by refining the microstructure and preventing excessive grain growth. The findings provide valuable insights into optimising forging conditions for high-performance RFW LAS joints in structural and industrial applications

Cold Metal Transfer (CMT) technology has emerged as a promising welding technique, offering numerous advantages such as reduced heat input, minimal spatter, and enhanced control over the welding process. This paper provides a comprehensive review of recent research developments in CMT technology, focusing on its history, variants, recent advancements, and future perspectives. Initially, the paper traces the historical development of CMT welding, highlighting its evolution and the introduction of various CMT variants with distinct characteristics and applications. Recent studies have focused on optimizing CMT process parameters to improve weld quality and productivity, leading to advancements in parameter control, arc stability, and wire feeding mechanisms. Additionally, research has explored the microstructural evolution and mechanical properties of CMT-welded joints for both similar and dissimilar metals, providing insights into material compatibility, joint design, and performance under various conditions. Specific applications such as Laser-CMT hybrid welding, CMT cladding, CMT wire arc additive manufacturing, and CMT welding for repair across various materials are examined, demonstrating the versatility of CMT technology. This review also addresses the challenges and methodologies for defect reduction in CMT welding, along with recommendations for best practices. Furthermore, the paper discusses the integration of artificial intelligence in CMT welding, exploring opportunities for enhanced weld quality, economic, and social implications, and future research directions.

Wire arc additive manufacturing (WAAM) is an advanced additive manufacturing (AM) technology that offers low cost and high deposition rates, making it suitable for building large metal parts for structural engineering applications. However, various welding procedures result in differing heat inputs and repetitive heating treatments throughout the deposition process, which can affect the microstructural and mechanical characteristics of the parts. In the current study, cylindrical parts made of 304L austenitic stainless steel (ASS) were manufactured using the WAAM technique, employing both gas metal arc welding (GMAW) and cold metal transfer (CMT) processes. This study explores the correlation between WAAM techniques and their effects on the bead geometry, microstructure and mechanical properties. The microstructure of the cylinders consisted of vertically growing austenite dendrites with residual ferrite (?) within the austenite (?) matrix. Compared to the bottom region (region ?), the top region (region ?) contained more residual ferrite. Although the microstructural characteristics from region ? to region ? are similar, they exhibit different ferrite morphologies. The rapid cooling rate in the CMT-AM process resulted in finer structures and a greater presence of ferrite phases in both regions compared to the GMAW-AM method. Cylinders produced by the CMT process displayed nearly uniform properties across both regions and demonstrated superior tensile properties, hardness, and impact toughness relative to those made using the GMAW technique. The WAAM 304L ASS cylinders also showed enhanced performance compared to stainless steel manufactured using traditional industrial forging standards, indicating that WAAM-processed 304L ASS cylinders are suitable for industrial applications.

The fabrication of dissimilar metal joints, particularly between AA 6061 aluminum alloy (Al) and AZ31B magnesium alloy (Mg), poses significant technical challenges due to their distinct metallurgical characteristics and the inherent difficulties associated with welding such materials. These challenges include the propensity for intermetallic compound formation, thermal cracking, and differences in thermal and mechanical properties between the two alloys. Cold Metal Transfer (CMT) welding, known for its low heat input and controlled metal transfer, offers a potential solution to these issues. However, optimizing the process parameters to ensure strong, defect-free joints requires a systematic approach. This study aims to optimize CMT welding parameters using parametric mathematical modeling (PMM) to produce high-strength Al and Mg dissimilar joints and to study the effects of CMT parameters on tensile strength (TS) and weld metal hardness (WMH), as well as the microstructural features of AA 6061 aluminum alloy/AZ31B magnesium alloy (Al/Mg) dissimilar joints. Al/Mg dissimilar butt joints were produced by the CMT process using ER4043 as filler wire. CMT, a low-heat input welding technique, was used to mitigate issues such as intermetallic compounds (IMCs), wider heat-affected zone (HAZ), and distortion. The CMT parameters, particularly wire feed speed (WFS), welding speed (WS), and arc length correction (ALC), were optimized using response surface methodology (RSM) to maximize the TS and WMH of the Al/Mg dissimilar joints. Polynomial regression was employed to create PMMs that integrated these CMT parameters to forecast the TS and WMH of the joints. An analysis of variance (ANOVA) was applied to assess the feasibility of the PMMs. The results indicated that the Al/Mg dissimilar joints, produced using a WFS of 4700 mm/min, a WS of 280 mm/min, and an ALC of 10%, exhibited higher TS and WMH values of 33 MPa and 95.8 HV, respectively. The PMMs provided precise forecasts for the TS and WMH of the Al/Mg joints with an error rate of less than 1% and a confidence level of 97%.

In the last two decades, wire arc additive manufacturing (WAAM) has emerged as a cost-effective alternative to traditional additive manufacturing (AM) processes, particularly for producing medium-to-large-scale components. The primary advantages of wire-based AM include simplified automated production and enhanced control and flexibility in the fabrication process. In this study, the gas metal arc welding (GMAW) process was used to produce cylindrical components from 2209 duplex stainless steel (DSS) using the WAAM technique. The mechanical properties and microstructural characteristics of the 2209 DSS cylinders were examined. The microstructure of the components varied from the bottom (region (1)) to the top (region (2)), resulting in a hardness difference between 301 HV0.5 and 327 HV0.5, and an impact toughness variation from 118 to 154 J. Additionally, the tensile properties exhibited anisotropic characteristics: the ultimate tensile strength and yield strength ranged from 750 to 790 MPa and from 566 to 594 MPa, respectively. The complex heat cycles and cooling rates during the WAAM process significantly affected the primary phase balance (50/50 austenite/ferrite) in the produced cylinder. In the GMAW-processed component, ?-phase precipitation was observed at the boundaries of the ferrite grains. The increase in the percentage of austenite from region (1) to region (2) was attributed to a decrease in the cooling rate and a longer time for solid-state phase transformation.

Direct energy deposition (DED) is an advanced additive manufacturing (AM) technique for producing large metal components in structural engineering. Its cost-effectiveness and high deposition rates make it suitable for creating substantial and complex parts. However, the mechanical and microstructural properties of these components can be influenced by the varying heat input and repeated thermal treatments associated with different welding procedures used during the deposition process. This study employed gas metal arc welding (GMAW) and cold metal transfer (CMT) arc welding techniques to fabricate cylindrical components from 2209 duplex stainless steel (DSS). The research investigated the impact of these welding methods on the microstructure and mechanical properties of the 2209 DSS cylinders. The intricate thermal cycles and cooling rates inherent in the DED process significantly influenced the primary phase balance, ideally comprising 50% austenite and 50% ferrite. In components processed using GMW, ?-phase formation was noted at the grain boundaries. Additionally, a slower cooling rate and extended time for solid-state phase transformations led to an increase in austenite content from the bottom to the top of the component. The cylinder fabricated using the CMT process exhibited fine austenite morphologies and a higher ferrite content compared to the GMW-processed cylinder. Furthermore, the cylinder produced using the CMT process showed consistent properties across the building direction, unlike the components manufactured with the GMW process. In terms of tensile properties, hardness, and impact toughness, the cylinder produced using the CMT technique outperformed the one made with the GMW process. Graphical Abstract: (Figure presented.)

Accelerated property mapping, an advanced indentation technique was used to describe the nanomechanical behaviour of duplex stainless steel (DSS) surfaces prior to and post heat treatments. Heterogeneity in deformation responses and relative elastic and/or plastic nature of DSS was assessed on longitudinal and transverse directions through load–displacement curves, property maps, histograms of hardness (H), modulus (E) and indentation works. Empirical ratios such as H/E, (H/E) 1/2, H 3 /E 2 and plasticity index were employed to understand the anisotropy across the directions.

The large structural components (304 L austenitic stainless steel) used in nuclear power plants are difficult and expensive to manufacture and machine using standard methods. Wire arc additive manufacturing (WAAM) is a low cost and high deposition method for fabricating large structural parts. Therefore, in this investigation, 304 L austenitic stainless steel (304 L ASS) cylindrical component was fabricated using WAAM technique. The mechanical and microstructural characteristics of the bottom (region ?) and top (region ?) of the WAAM 304 L ASS component are studied. The microstructure of region ? consists of austenite and ferrite with vermicular and lathy morphologies, while region ? consists of skeletal and reticular morphologies. In regions ? and ?, yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) were found to be 350 ± 7 MPa, 562 ± 10 MPa, and 75 ± 1%, respectively. The impact toughness and hardness in regions ? and ? were found to be 112 ± 2 J and 183 ± 6 (Hv0.5), respectively. From the results, it is evident that the tensile properties of the WAAM 304 L ASS component were equal/greater than the values of the forged 304 L ASS material, wrought 304 L ASS alloy, and 304 L ASS filler wire.

The proliferation of Wire Arc Additive Manufacturing (WAAM) has significantly enhanced the production capabilities for lightweight and structurally robust components. This study investigates the microstructural characteristics, tensile properties, and preliminary wear performance of AA 5083 aluminum alloy processed via WAAM, focusing on applications for lightweight structures. Using SEM and XRD, microstructural changes during the WAAM process are analyzed, and tensile testing evaluates the mechanical properties, including ultimate tensile strength (UTS) and elongation. The results reveal that the microstructure consists of ?-Al and ?-(Al5Mg8) phases, with the Al5Mg8 phase distributed along grain boundaries and within grains. Notably, the grain size in the Y-direction (building direction) is larger than in the X-direction (deposition direction) due to temperature variations during processing. Tensile testing shows that horizontal samples (X-direction) have a UTS of 295 ± 5 MPa and elongation of 20.08 ± 0.8%, while vertical samples (Y-direction) have a UTS of 267 ± 10 MPa and elongation of 16.43 ± 2.1%. This results in an anisotropy of 9.4% in tensile strength, reflecting the differences in mechanical properties between the two directions. The WAAM AA 5083 aluminum part exhibits a maximum wear rate of 5.22 × 10?³ mm³/m and a coefficient of friction of 0.52 at a load of 3.5 kg and 450 rpm. Under these conditions, deep grooves, layer separation, and load-induced deformation are observed. The primary wear mechanisms include delamination, adhesion, and abrasion. Hardness levels are consistent in the X-direction and show minimal variance in the Y-direction, with an average hardness of 89.4 ± 5.14 HV0.5. The study demonstrates that WAAM-produced AA 5083 aluminum alloy, with an anisotropy below 10%, is suitable for real-time lightweight structures, offering effective performance in engineering applications such as aerospace and automotive industries. Future research should focus on further quantifying wear behavior and optimizing processing conditions to enhance material performance for specific applications.

Streetscape design can encourage social interaction and community building, creating a sense of place and improving the overall well-being of the resident community. Detailed investigation of streetscape quantitatively can identify the opportunities to reduce energy use, improve air quality, and enhance the natural environment. Data derived from street view services are typically used to analyze the streetscape. However, the availability of street view services is limited to selected regions, because of which conducting a study for an area deprived of street view services is a challenge. Building on this gap, this study proposes a new system introduced as Urban scan to overcome the limitation. •The proposed system can capture the streetscape in 360°.•Helps to analyze the streetscape composition with the least computational effort.•The accuracy of the classification is tested with different datasets and is noted to be above 96.02%.