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In the modern era, the demand for lightweight and high-strength aluminium matrix composites (AMCs) has significantly grown as a result of their structural applications in various sectors. The distinctive characteristics of AMCs are intricately impacted by variables like the type and weight percentage (wt.%) of reinforcement, the selection of processing techniques, and the matrix employed. Fabricating hybrid AMCs poses several challenges, including achieving desired geometrical shapes, homogeneous mixing of reinforcements, addressing porosity, and ensuring strong interfacial bonding of reinforcement-matrix interfaces. Stir-squeeze casting has emerged as a non-traditional casting technique with the potential to address these challenges effectively. This study intends to look into the impacts of the distinct reinforcement particles (Al2O3, SiC, Si3N4, and BN) with varying wt.% on the development of different configurations of hybrid AMCs based on AA2024. The key properties that have been examined include porosity, ultimate tensile strength (UTS), elongation percentage (EL%), hardness, and impact energy of developed hybrid AMCs. The results reveal that UTS (235.6 to 377.8 MPa) and hardness (51.5 to 85.1 HRB) significantly increased with the addition of reinforcement particles, while EL% (11.6 to 7.9%) and impact energy (6.62 to 5.61 J) decreased. AA2024/2%Al2O3/2%SiC/2%Si3N4/2%BN outperformed in terms of UTS and hardness and gave 60.36% and 65.24%, respectively; however, the porosity, EL%, and impact energy have been compromised from the matrix material (AA2024) by 1.61%, 31.89%, and 15.26%, respectively. Fractography analysis of UTS and Charpy impact fractured samples depicts that a dimple fracture has been observed for the AA2024 without any reinforcement. However, with the inclusion of particles for reinforcing (Al2O3, SiC), the fabricated AMC AA2024/2%Al2O3/2%SiC provided the cleavage fracture, while transgranular cleavage fractures have been observed in the fractured surfaces of the third and fourth configurations (AA2024/2%Al2O3/2%SiC/2%Si3N4, AA2024/2%Al2O3/2%SiC/2%BN). Moreover, the brittle fracture has been depicted in the broken sample of AA2024/2%Al2O3/2%SiC/2%Si3N4/2%BN. [ABSTRACT FROM AUTHOR]

This study proposed the direct extrusion and continuous-shear deformation (DECS) process for the co-extrusion of Mg-AZ31B/Al 6063, aiming to prepare high-plasticity Mg/Al composite sheets. The effect of extrusion temperature on the microstructure and mechanical properties of the Mg/Al composite sheet was systematically studied. The results show that Mg/Al composite sheets with no voids or cracks at the interface were successfully prepared by the DECS process. The microstructure of the Mg layer at different extrusion temperatures primarily consists of equiaxed fine grains, with grain sizes of 7.29 μm, 8.98 μm, and 9.88 μm at 330℃, 360℃, and 390℃, respectively. The Mg layer exhibits a typical extrusion texture, with the c-axis of most grains parallel to the transverse direction (TD). With the increase in extrusion temperature, the c-axis of some grains deviates from the TD toward the normal direction (ND). The Al layer mainly consists of elongated deformed grains and fine dynamically recrystallized (DRXed) grains distributed along the extrusion direction (ED). The AZ31 Mg alloy with refined grains maintains the ultimate tensile strength of the Mg/Al composite sheet, while the Al matrix enhances its plasticity. At 330℃, the Mg/Al composite sheet shows an ultimate tensile strength of 244.48 MPa ± 4.35 and an elongation of 39.42% ± 0.06. The influence of the bonding layer thickness on the shear and tensile properties of the composite sheet was studied, revealing that increasing the bonding layer thickness reduces the shear strength of the Mg/Al composite sheet but positively affects its tensile strength. [ABSTRACT FROM AUTHOR]

Producing bulk high-specific strength materials that replace steel airframe structures like stringers is the only optimistic alternative that can meet the future needs of the aviation sector. Stir casting, a prominent fabrication route to produce bulk materials, is employed in the current investigation to prepare aluminum composites reinforced with graphene nanoplatelets. However, the influence of dross on reinforcement infiltration into melt is unexplored by researchers and hence essential. The critical experimental insights reveal that dross hinders the nanoreinforcement incorporation into the melt; i.e., 25 to 40% of introduced GNPs are entrapped in dross. Moreover, superior mechanical behavior with an ultimate tensile strength (UTS) of 203 MPa led by a good uniform distribution of GNPs with no evidence of voids and clusters is observed for 1.5 wt.% GNP cast sample. Quantitative X-ray maps and EDS analysis reveal no iron contamination and their intermetallic compounds that degrade the strength of cast samples. [ABSTRACT FROM AUTHOR]

Submerged arc welding (SAW), renowned for its high deposition rate and superior weld quality, is the go-to method for joining thick metals in heavy structures. However, industry beams and columns welded with SAW can exhibit detrimental defects like undercut, porosity, and burn-through, significantly impacting weld properties. This study addresses this challenge by presenting a multi-objective optimization approach for SAW parameters on AISI 1020 mild steel. Aiming to optimize tensile strength, hardness, and bead width, the study employs Taguchi's design of experiments and couples the multi-objective Jaya algorithm with an artificial neural network (ANN). This synergistic combination yielded optimal process parameters: 417 A welding current, 20.7 mm electrode stick-out, 33.7 V voltage, and 505.8 mm/min transverse speed. These settings translated into exceptional weld characteristics, with ultimate tensile strength reaching 427 MPa, hardness of 73.9 HRB, and bead width of 14.29 mm. Confirmation tests further validated these findings, demonstrating minimal error and solidifying the effectiveness of the optimization approach. This research paves the way for enhanced weld quality and process control in heavy structural applications. [ABSTRACT FROM AUTHOR]

This investigation elucidates the impact of 3D printing parameters, encompassing the infill pattern variations (cross, grid, line, triangle, and tri-hexagon) and infill percentages (10%, 30%, 50%, 70%, and 90%), on the mechanical behavior of the PLA/Cu composite. A 3D model of the tensile specimen was designed in accordance with the ASTM D1708 standard and subsequently printed using carefully chosen printing parameters. Subsequent to fabrication, the samples were subjected to tensile testing. Scanning Electron Microscopy (SEM) imaging, along with Energy-Dispersive X-ray (EDX) analysis, was carried out for the fabricated specimens. Additionally, SEM analysis was performed on the fracture surface of the specimens. Tensile tests were performed on all printed samples, encompassing various patterns and infill percentages. The resulting tensile data were analyzed and discussed with a focus on parameters such as toughness, ultimate tensile strength (UTS), Young's modulus, and strain at UTS. The maximum UTS observed was 13.69 MPa, occurring in specimens with a line pattern at an infill density of 90%. In contrast, the minimum UTS recorded was 4.5 MPa for samples utilizing a triangle pattern at 50% infill density. The highest Young's modulus measured, 275.6 MPa, was achieved with the line pattern at 90% infill density, whereas the lowest recorded Young's modulus, 92 MPa, was associated with the triangle pattern at 10% infill density. Furthermore, the maximal strain at UTS (30%) was exhibited by the tri-hexagonal pattern at 50% infill density, while the minimal strain (10%) was observed in the line pattern at 70% infill density. [ABSTRACT FROM AUTHOR]

The possibility of obtaining a combined titanium-steel construction by directed energy deposition using vanadium or vanadium/nickel interlayers has been investigated. Vanadium wire VnPr-1, nickel wire NP1 grade, and welding wires Sv-08G2S, 316L, and MSG NiFe-1 grades were used for deposition on the end of the titanium plate VT1-0. The use of vanadium as an interlayer deposited on titanium makes it possible to provide a joining with a stable structure, steady hardness distribution, and acceptable manufacturability. The content of dissolved titanium in the vanadium layer has a negative effect on the subsequent deposition of steel, nickel, or iron-nickel alloy. Therefore, the titanium content was reduced to a level of less than 0.5% by the deposition of at least 4 vanadium beads. The results of tensile tests demonstrated that all specimens failed in the elastic section mostly along the interlayers between vanadium and subsequent layers of low-carbon steel, nickel, and iron-nickel alloys deposited on it. The greatest ultimate tensile strength is achieved in the specimen, which is a compound of titanium and steel through interlayers of vanadium and iron-nickel alloy, and constitutes 251 MPa. The only specimen was destroyed along the titanium-vanadium interlayer probably due to brittle ω–phase formation. [ABSTRACT FROM AUTHOR]

Orbital friction stir welding (FSW) is a promising approach to joining clad pipes. In this work, the influence of individual process parameters on the material flow even as, mechanical properties in orbital friction stir welded clad pipes is investigated. Due to the local heterogeneous microstructures within the weld, joints were evaluated by optical and scanning electron microscopy (SEM), microhardness, and digital image correlation (DIC). A microhardness increase was observed, with a maximum of 380 HV0.5 within the Inconel 625 and 265 HV0.5 within the X65 steel stir zones. Sound joints had an average ultimate tensile strength (UTS) exceeding up to 13% of the calculated theoretical tensile strength, which is obtained considering the minimum tensile strength of both materials. Additionally, failure occurred in the base material during the tensile testing, where the local strain in the stir zones of the X65 steel and Inconel 625 were only 3.3% and 10%, respectively. In summary, this investigation shows friction stir welded joints of API X65 steel and Inconel 625 clad pipes with high mechanical properties. [ABSTRACT FROM AUTHOR]

This paper explores the potential to hot stamp third-generation steels, in this case, a 980 MPa grade, while retaining or improving on the as-received microstructure, in particular the retained austenite (RA) fraction, and corresponding strength and ductility. Three classes of thermomechanical processes were investigated using a thermo-mechanical simulator system (Gleeble 3500). The first two processing routes considered a quenching and partitioning process starting from either a fully austenitic condition prior to quenching, designated the "Q&P" process, or an inter-critical partial austenitic condition, designated the "IC Q&P" process. In the two simulated Q&P processes, the samples were quenched to a predetermined temperature and then immediately transferred to a partitioning furnace. In the third processing route, designated the "Q&T" process, the samples were partially austenitized and then quenched to room temperature, followed by a tempering process to restore ductility. The conventional Q&P process resulted in excessive martensite formation, with high hardness and low ductility. The Q&T process produced a tempered martensite microstructure with hardness equivalent to the as-received sheet but with lower elongation and bendability. The IC Q&P heat treatment process increased the amount of retained austenite compared to the as-received sheet which translated into a higher yield strength, total elongation, and v-bend fracture angle. The IC Q&P ultimate tensile strength was approximately 8% lower than that of the as-received material. A sensitivity study was conducted to evaluate the influence of variations (± 25 °C) in the intercritical austenitization temperature, quench temperature, and partitioning temperature on the resulting microstructure and microhardness. The final mechanical properties were observed to be relatively independent of these process variations, indicating that the IC Q&P hot stamping process appears to be robust. [ABSTRACT FROM AUTHOR]

The deposition of cladding titanium (Ti) alloy layers on aluminum (Al) alloy components via wire-arc additive manufacturing (WAAM) has many attractive properties but is also significantly challenging because the deposition of a molten Ti alloy in a high-temperature state causes Ti and Al alloys to melt and mix. This leads to serious problems such as the formation of brittle intermetallic compounds (IMCs), lower forming dimensional accuracy (the formation of beads with side overhang and hump defects), and the generation of cracks and voids in the dissimilar metal interface. This study aimed to comprehensively investigate these challenges, in particular, the effect of WAAM path strategies on the forming dimensional accuracy. A pure Ti bead equivalent to ERTi-2 was deposited on an Al alloy plate equivalent to 5052 using stringer and weaving strategies. As a result, cladding ERTi-2 multi-beads on a 5052 plate without fusion defects were successfully fabricated using weaving strategies. In addition, the formation mechanisms for hump defects and severe spatter were clarified by observing the behavior of the molten pool. We also examined the formation of brittle IMCs and low mechanical properties. Tensile tests results showed an ultimate tensile strength of 54 ± 18 MPa (average ± standard deviation) at the dissimilar metal interface. According to fractographic analysis, the irregular formation of microcracks at the thicker IMC layer reduces bonding strength. The formation of the IMC layer is a result of the concentrated heat input in the directed energy deposition (DED) process, and is not due to the weaving strategy. [ABSTRACT FROM AUTHOR]

This study examines the welded joint between P91 steel and Incoloy 800HT using the activated tungsten inert gas (A-TIG) welding process. The focus is on analyzing the microstructure and evaluating the mechanical properties of joints made with different compositions of activating flux. Owing to the reversal of the Marangoni effect in which the conventional direction of molten metal flow in the weld pool is reversed due to the application of oxide-based fluxes, a complete depth of penetration of 8 mm was successfully achieved. Conducting mechanical tests, such as microhardness, tensile, and Charpy impact toughness tests, elucidates the behavior of the welded specimens under different loading conditions. The findings highlight the effects of grain size, dislocations, and the evolution of fine-sized precipitates in the high-temperature matrix. This study highlights the importance of choosing suitable flux compositions to achieve consistent penetration and dilution in the base metals. Insights into different failure modes and the influence of temperature on the tensile strength were evaluated. Beneficial mechanical properties of the joints (meeting the criteria of ISO and ASTM standards) were found: ultimate tensile strength of 585 ± 5 MPa, elongation 38 ± 2%, impact toughness of 96 ± 5 J, and maximum microhardness of 345 ± 5 HV. [ABSTRACT FROM AUTHOR]

This paper investigates the mechanical properties of AA2024 joints welded using the Friction Stir Welding (FSW) process, with a particular focus on comparing joints made with and without the inclusion of a commercially pure copper sheet between the edges being welded. The study aims to understand the influence of weld heterogeneity on the mechanical properties of FSW joints. Various joints were fabricated with a copper interlayer, and optimal process parameters—rotational speed, advancing feed, and tool geometry—were identified. Mechanical tests, including Rockwell B and Vickers hardness (HV) tests, as well as tensile tests, were conducted on both homogeneous and heterogeneous joints. The results showed that the presence of copper significantly affected the hardness distribution, particularly in the weld nugget. Heterogeneous joints demonstrated a notable increase in HV at the nugget and a reduced weld-affected area on both the advancing and retreating sides. The study found a strong correlation between process parameters, tool geometry, and the Ultimate Tensile Strength of the joints. Optimal mechanical properties were achieved in heterogeneous joints welded at 800 rpm and 40 mm/min with an 18 mm tool, resulting in a joint efficiency of 73%. These parameters differed significantly from those optimized for homogeneous joints, which were 1200 rpm and 100 mm/min with a 16 mm tool. It was also observed that exceeding 1000 rpm in rotational speed and 70 mm/min in feed speed is not advisable for heterogeneous welds. Future research should explore varying amount of copper and other materials, as well as different interposition methods, to further understand their effects on the mechanical properties of FSW joints. [ABSTRACT FROM AUTHOR]

Nowadays, H13 steel is commonly utilized in processes such as pressure die casting, extrusion, and drop forging as well as in tube and glass manufacturing, however with limited manufacturability. The current research focuses on the effects of crucial process-related additive manufacturing parameters on the mechanical behavior of H13 hot work tool steel manufactured by the selective laser melting (SLM) additive manufacturing (AM) technique. The investigated parameters were the scan speed, the laser power, and their output volumetric energy density (VED) on the mechanical and morphological properties utilizing tensile and nanoindentation tests as well as scanning electron microscope (SEM). The results of this study revealed that it is possible to manufacture H13 steel parts with high mechanical performance using the SLM additive manufacturing technique. Specifically, the ultimate tensile strength reached a peak value at 1836 ± 48 MPa, while the yield tensile strength was found at 1468 ± 30 MPa. These parts are comparable to those made with conventional materials. A die part made using SLM was tested in the aluminum extrusion process on an 18 MN extrusion press producing acceptable quality extrudates and verifying its functionality and resilience under the high pressure and temperature of the extrusion process. [ABSTRACT FROM AUTHOR]

Lightweight bent aluminum profiles are widely utilized in transportation fields. In this paper, the torsional channel self-bending extrusion process (TCSE) was adopted to machine AA6063 bent aluminum profiles in a single operation to verify the process's feasibility. Effects of extrusion parameters on the curvature, microstructure, and mechanical properties of the profiles were researched, and the extrusion process was simulated. The results show that the extruded profiles had good curvature stability. The grains were equiaxed in the cross longitudinal section, and the grain size at the outside diameter (OD) position was smaller than the inside diameter (ID) position. When the difference in deformation temperature at the OD edge was above 31 K, a smaller peripheral coarse grain (PCG) layer was formed at the OD edge with a thickness of about 400 μm, resulting in reduced hardness. The Mg2Si particles served as the main strengthening phase, which increased in number and decreased in size with increasing billet temperature and extrusion speed. Increasing the billet temperature and speed improved the mechanical properties of the material, with an increase in average hardness of 55.9% and 19.5%, and ultimate tensile strength (UTS) of 12.5% and 7.1%, respectively. By comprehensively considering the factors of extrusion load, microstructure, and mechanical properties, the optimum bent profile for different curvatures was determined. When a large curvature (≥328.67 mm) was required, it was preferred to increase the billet temperature. When a smaller curvature (≤328.67 mm) was required, it was advisable to increase extrusion speed. [ABSTRACT FROM AUTHOR]

In the present work, the effect of build-up orientation angle and printing speed on mechanical properties of 17-4 PH stainless steel components realized by Bound Metal Deposition technology was investigated. Furthermore, the presence of microscopical and macroscopical defects was analyzed as a function of the printing parameters investigated. To this purpose, tensile specimens, printed with different build-up orientation angles (0°, 45°, and 90°) and printing speeds (15, 30, 45, and 60 mm/s), were tested at room temperature to evaluate the mechanical properties as a function of the process parameters. Furthermore, stereo optical microscopy and scanning electron microscopy coupled to energy dispersive X-ray spectroscopy were used, respectively, to observe the macroscopical and microscopical defect presence on the 3D printed parts built with different build-up orientation angles and printing speeds. It was demonstrated that the build-up orientation angle and printing speed significantly affect the mechanical properties and the surface finish of 3D printed components, as well as the presence of micro-defects due to the layer-by-layer filament deposition. In particular, the build-up orientation angle of 45° confers less mechanical to the specimens than the other two orientations investigated, both in terms of ultimate tensile strength, yield strength, and modulus of elasticity. Furthermore, high print speeds do not significantly contribute to a worsening of mechanical performance but influence the surface finish which is characterized by greater printing defects. [ABSTRACT FROM AUTHOR]

The work is devoted to the study of bimetallic structures "titanium-steel" by electron beam freeform fabrication with the use of niobium and copper interlayers. A metallographic study of the deposited interlayers is carried out. The hardness distribution over the samples is shown. Technological issues according to deposition of niobium on titanium and steel on copper are pointed out. Tensile testing results reveal that the obtained structures have an ultimate tensile strength of 150–228 MPa and the fracture is located at the niobium-copper alloy side or at the niobium interlayer. The need to reduce the titanium content in niobium due to the occurrence of intergranular penetration of copper is demonstrated. [ABSTRACT FROM AUTHOR]

This article presents the results of pilot studies on the lubrication of the blankholder zone in sheet metal forming using a pressurised lubricant. The authors invented a method and built a special tribometer for pressure-assisted lubrication. This approach reduces friction in sheet metal forming processes compared to conventional lubrication. Moreover, the artificial neural network approach combined with a force-directed Fruchterman-Reingold graph algorithm and Spearman's correlation was used for the first time to analyse the relationships between the friction process parameters and the output parameters (the coefficient of friction and the resulting surface roughness of the sheet metal). The experimental tests were conducted utilising strip drawing on four grades of steel sheets known to be outstanding for deep-drawing quality. Different oils, oil pressures and contact pressures were used. Artificial neural network models were used for the first time to determine these relationships in a strip drawing test where every parameter is represented by one node, and all nodes are connected by edges with each other. R Software version 4.2.3 was used to construct the network using the 'qgraph' and 'networktools' packages. It was found that friction conditions had a highly significant negative correlation with coefficient of friction (COF) and a moderately significant negative correlation with the final surface roughness. However, the initial surface roughness of the as-received sheets had a negative correlation with the COF and a positive one with the resulting surface roughness of the sheet metal. The parameters most related to the COF are the strength coefficient, the ultimate tensile strength and the friction conditions (dry friction or pressurised lubrication). Spearman's correlation coefficients showed a strong correlation between the kinematic viscosity and the friction conditions. [ABSTRACT FROM AUTHOR]

This paper investigates the cold spray additive manufacturing of a thick wall made of pure Al powder with a granulometry of + 45–15 μm with a size d50 = 26.95 µm. A high wall with vertical lateral faces is obtained without clogging, using a compensation building strategy and gas pressurization at 30 bars, 400°C. Layer by layer, using a suitable set of deposition parameters, the profile of the deposit grows without a lack of material at the lateral edges and then produces the near-net shape 3D wall. However, a structural characterization shows an issue of pore development and low mechanical properties. A porosity with a typical pore size range of 6–100 µm is observed from the bottom zone to the top zone of the wall, with a random occurrence and with a fraction of pores up to 8%. The distribution of the pore size shows a high fraction of fine pores (6–10 µm) up to ~ 70%. There can be a weak fraction (~ 0.04%) of larger pores (130–200 µm) and such pores appear as a continuous connexion of pores within the deposit due to a bad stacking and a bad bonding of particles during the additive growth. These detrimental defects ease the brittle mechanical behaviour of the wall during a tensile test. An intergranular-like fracture is observed with some trace of dimples but the brittle stress/strain curve until rupture suggests a predominant failure by cleavage due to the porosity. The fracture strain is less than 2%. The ultimate tensile strength and the elastic modulus are limited to about 50 MPa and about 50 GPa, respectively. [ABSTRACT FROM AUTHOR]

The demand for 3D-printed high-performance polymers (HPPs) is on the rise across sectors such as the defense, aerospace, and automotive industries. Polyethyleneimine (PEI) exhibits exceptional mechanical performance, thermal stability, and wear resistance. Herein, six generic and device-independent control parameters, that is, the infill percentage, deposition angle, layer height, travel speed, nozzle temperature, and bed temperature, were quantitatively evaluated for their impact on multiple response metrics related to energy consumption and mechanical strength. The balance between energy consumption and mechanical strength was investigated for the first time, contributing to the sustainability of the PEI material in 3D printing. This is critical considering that HPPs require high temperatures to be built using the 3D printing method. PEI filaments were fabricated and utilized in material extrusion 3D printing of 125 specimens for 25 different experimental runs (five replicates per run). The divergent impacts of the control parameters on the response metrics throughout the experimental course have been reported. The real weight of the samples varies from 1.06 to 1.82 g (71%), the real printing time from 214 to 2841 s (~ 1300%), the ultimate tensile strength from 15.17 up to 80.73 MPa (530%), and the consumed energy from 0.094 to 1.44 MJ (1500%). The regression and reduced quadratic equations were validated through confirmation runs (10 additional specimens). These outcomes have excessive engineering and industrial merit in determining the optimum control parameters, ensuring the sustainability of the process, and the desired functionality of the products. [ABSTRACT FROM AUTHOR]

The rheological, mechanical, and electrical properties and structure of rods and wires made of aluminum alloy concentration of 1% REM (0.6% Ce and 0.4% La) are investigated and presented. The rods were produced by combined rolling-extrusion (CRE) from two different types of billets: casting into a mold 14×14 mm and into electromagnetic mold (EMM) Ø12.5 mm. A database of the DEFORM 3D complex was created for computer modeling of the CRE process. The tensile strength of rods Ø9 and 5 mm obtained using CRE method is 120–140 MPa and elongation to failure is 15–26% for billets from EMM. For billets 14×14 mm, the ultimate tensile strength is 112–125 MPa, which is comparatively lower than that of rods made from round billets (elongation to failure is 26–34%). The plastic properties of the final wire Ø2 mm from a round billet after EMM are higher than wire Ø2 mm from a billet obtained by casting into a mold 14×14 mm. Rods after CRE from both types of billets are characterized by fairly high ductility. To obtain Ø2-mm wire from rods, no intermediate annealing was required. The values of electrical resistance are taken from 0.02271 to 0.0301 Ω‧mm2/m for rods from 12.5-mm billets and from 0.02776 to 0.03413 Ω‧mm2/m for rods from billets 14×14 mm. The electrical resistance values for wire Ø2 mm from billets 14×14 mm are higher than for wire obtained from rods after EMM. Microstructure shows that the final wire after CRE from billet in EMM has a more extensive structure than after CRE from billets with dimensions of 14×14 mm. [ABSTRACT FROM AUTHOR]

2219 aluminum alloy thin-walled tubes were fabricated by multi-pass spinning process, and then heat treatments were employed to optimize the mechanical properties of the spun tubes. It is shown that severe deformation during the spinning leads to the formation of large number of nanoscale subgrains, which causes the decrease of work hardening rate, ultimate tensile strength, and fracture strain. The solid solution at 530℃/30 min results in the full recrystallization and leads to the disappearance of the nanoscale subgrains. Besides, the micron scale precipitates in the as-spun tubes are refined to be nanoscale via the further aging process conducted at 175℃/18 h. It is why the ultimate strength of the tubes is enhanced from 245 to 435 MPa. By using of the spun tubes, 2219 aluminum alloy bellows with four circumferential waves were successfully formed by multi-step single wave hydroforming process. [ABSTRACT FROM AUTHOR]

This study investigates the influence of surface finish and post-processing conditions on the mechanical properties of 17-4 PH stainless steel (SS) produced using the atomic diffusion additive manufacturing process (ADAM). Diverse sample orientations, including horizontal (0°), 30°, 60°, and vertical (90°), were examined, with selected samples undergoing post-processing through machining, polishing, and heat treatment. Tensile strength testing, surface roughness measurement, and hardness measurement were conducted to assess the effect of surface finish conditions and post-processing on mechanical properties. The results reveal significant variations in the tensile strength of the samples based on the build orientation (183.5 to 1034.5 MPa), and subsequent machining. Notably, post-built machining is found to enhance both the absolute ultimate tensile strength (UTS) and the isotropy of the material. Further improvements are attainable through heat treatment. A microstructure analysis, in conjunction with tensile testing outcomes, demonstrates the potential for refining the properties of ADAM-printed samples through suitable machining, heat treatment, and geometry modifications. This study identifies avenues for ongoing process development and outlines possibilities for enhancing mechanical properties of additive manufactured parts, particularly through ADAM process. [ABSTRACT FROM AUTHOR]

The joining of titanium and stainless steel is challenging with conventional filler metals due to the formation of Fe-Ti intermetallic compounds (IMCs). Therefore, a filler that is compatible with both metals is necessary to avoid these IMCs and enhance the mechanical properties of Ti-SS joint. This research aims to investigate the effect of novel Nb-Cu composite filler on mechanical and microstructure properties of TA7-SS304 dissimilar hybrid composite joints using gas tungsten arc welding (GTAW) process. The mechanical properties: ultimate tensile strength (UTS) and micro hardness have been analyzed and assessed through the microstructure of weld interfaces and fracture zones. Results revealed that welding current (I) affects the UTS significantly whereas micro hardness is greatly influenced by welding speed (Ws). The maximum UTS of 293 MPa and micro hardness of 100 HV as well as minimum tensile residual stresses of 180 MPa and 170 MPa on SS 304 and TA7 sides, respectively have been attained at optimal parameters of I = 40 A, Ws = 150 mm/min and GFR = 18 lit/min. SEM and EDS analysis showed that presence of Cu and Nb solid solutions in the fusion zone contributed to improvement in UTS. Ductile fracture surface with no prominent defects is obtained at optimal combination, while brittle fracture with voids and cavities is observed for low-strength joints. X-ray diffraction analysis depicted that the formation of TiFe, Ti2Fe, and TiFe2 compounds and direct mixing of base metals have been successfully inhibited by using Nb-Cu composite filler which improved the Ti-SS bonding. [ABSTRACT FROM AUTHOR]

Square butt joints were prepared using two microalloyed ASTM A572 Gr.50 steels: niobium (Type 1) and vanadium (Type 2). Both single-wire submerged arc welding (SAW) and two-wire tandem submerged arc welding (SAW-T) processes were utilized, with a constant heat input of 2.5 kJ/mm. The weld profile, microstructure, and mechanical properties were systematically analyzed for both welding processes. It was observed that the weld width, hardness, yield strength, ultimate tensile strength, and impact toughness of the welds increased with SAW-T compared to SAW. Type 1 steel weld exhibited higher acicular ferrite, 8% higher yield strength, and 5% higher ultimate tensile strength due to the intra-granular nucleation of niobium carbonitrides in austenite. In contrast, Type 2 steels displayed a 13% higher percentage of elongation, 4.3% higher hardness, and 30% higher impact toughness at 25 °C. At − 20 °C temperature, SAW-T welds show higher HAZ toughness than SAW welds. Also, Type 2 welds showed enhanced toughness compared to Type 1 welds by mitigating the pinning effect of precipitates. [ABSTRACT FROM AUTHOR]

This study investigates the effect of laser treatment parameters on the tensile behavior of H13 tool steel in both quenched and tempered conditions. The effects of varying laser parameters on ultimate tensile strength and elongation at fracture which is the aim of this research were explored by employing a bionic unit to apply laser treatment with two parallel lines on the steel surface. These parameters are crucial for understanding material performance under tensile stress. Statistical analysis, including an analysis of variance (ANOVA), and fractographic analysis using SEM were conducted to analyze the results. The findings reveal a significant enhancement in the ultimate tensile strength of the laser-treated samples, with values ranging between 1342.27 and 1497.25 MPa, surpassing the non-treated substrate’s strength of 1247.23 MPa. However, a decrease in elongation at fracture was observed, indicating increased brittleness post-laser treatment, with elongation values notably lower than the non-treated sample’s 14.71%. The hardness values within the laser-treated zone exhibited a high variance, with the highest values found in the hardened zone ranging from 65.7 to 61.4 HRC, suggesting the formation of fine carbides and lath martensite due to rapid cooling and martensitic transformation. Furthermore, the depth of the laser-transformed zone, significantly influenced by laser power, varied between 1.30 and 1.9 mm, highlighting the critical role of laser parameters in affecting material properties. The study highlights a critical balance between ductility and strength in laser-treated H13 tool steel, which is essential for optimizing the material’s performance for industrial applications. [ABSTRACT FROM AUTHOR]

For a past few years, laser powder bed fusion (LPBF) process faced many issues such as cavity creation, unstable thermal capillary convection, and thermodynamic instability during the printing of Cu-Cr-Zr alloy. Hence, the important LPBF process variables such as exposure duration (ED) of 300, 400, and 500 µs; laser power (LP) of 370, 420, and 470 W; and overlapping percentage (OP) of 20, 40, and 60% needs to be examined based on the interactions of various combinations of parameters to fabricate a Cu-Cr-Zr alloy parts with reduced porosity, maximum ultimate tensile strength (UTS), and minimum nano-indentation depth (NID). Moreover, analytical studies were also performed based on the COmplex PRoportional ASsessment (COPRAS) approach. The proposed analytical approach shows better concurrence with the experimental observations. The optimal and initial variables obtained from the analytical and experimental approach were compared. The Cu-Cr-Zr alloy printed with optimal parameter settings possesses maximum UTS of 367 MPa and minimum NID of 321.51 nm. These enhanced results were mainly due to the occurrence of reduced porosity of 0.27%. Moreover, FESEM based fracture mechanism were investigated to study the propagation of cracks based on the defects formation. [ABSTRACT FROM AUTHOR]

The double-pass butt welding process was carried out on 9-mm-thick 2014-T4 aluminum alloy T-joints by stationary tool shoulder friction stir welding (STS-FSW). Microstructure changes were analyzed by grain and EBSD, combined with the evolution of the precipitation phase, to explore the influence of regulations of different process parameters on T-joints' mechanical properties. Defect-free T-butt joints were obtained within the rotational speed range of 400–500 rpm and the welding speed range of 100–140 mm/min. Due to severe dynamic recrystallization, the weld nugget zone exhibits fine equiaxed grain characteristics, with a grain size of approximately 10 μm. The degree of recrystallization and deformation in the weld nugget overlapped zone (WNOZ) did not significantly change, and the grain size of WNOZ was approximately 4 μm. T-joints' hardness has an uneven distribution, and the hardness is greatest in the weld nugget zone at 110–125 HV. The T-butt joints have the weakest hardness at the skin and stringer in the TMAZ, approximately 70–80 HV. The ultimate tensile strength of the skin and stringer in the T-butt joints is equivalent to 85% and 59.6% of the base material. According to the fitting of a quadratic polynomial with multiple variables, it is found that the maximum tensile strength of the skin and stringer can only be achieved when the thermal input is within a reasonable range. The fracture is a ductile fracture with numerous dimples visible on the fracture surface. The tensile fracture of the specimen is analyzed by the finite element method. T-butt joints exhibit lower stress concentrations during the tensile test than T-fillet joints. [ABSTRACT FROM AUTHOR]

The milling process is the standard method for producing flat tensile test specimens from sheet metal. However, alternative methods employed in the industry for cutting sheet metal include abrasive water jet cutting, laser cutting, punching, and, to a lesser extent, electrical discharge machining. Among these, abrasive water jet cutting stands out for its superior material integrity, versatility, precision, and efficiency, making it a preferred choice. Previous studies consistently show that specimens cut by abrasive water jetting exhibit lower ultimate tensile strength and higher percent elongation than those obtained by milling in standardized tensile tests. This study investigates this behavior across different types of steel and alloys. Both steel types were subjected to milling and water jetting processes, followed by an analysis of their experimental and simulated mechanical behavior to identify discrepancies between the two methods. The findings suggest that milling, influenced by factors such as feed per tooth and cutter diameter, introduces geometric stress concentrators. This relative increase in ultimate tensile strength and decrease in percent elongation are observed consistently in milled tensile specimens compared to those cut by water jet, regardless of material type or thickness. Additionally, the effects of perimeter hardening resulting from superficial plastic deformation caused by the cutting edge, likely due to its small thickness, do not influence the observed trends significantly. [ABSTRACT FROM AUTHOR]

The water as a welding environment may generate serious technological and metallurgical problems but in certain cases, the physicochemical properties of water can be used effectively, e.g., to impart the specific properties of welded materials. The purpose of the work was verification of effectiveness of the water cooling of aluminium alloy AA5754 for various sets of technological parameters of underwater friction stir welding (UFSW). For the joints performed with the range of parameters of rotational speed: 475–925 rpm and welding speed: 47.5–95 mm/min, the following examinations were carried out: visual tests, radiographic tests, static tensile test, fractography (SEM, scanning electron microscope) analysis, and surface texture analysis performed with 3D measurement system. All of the joints were characterized with some amount of flash. Besides, depending on the values of selected parameters, the defects arising from inadequate stirring were found—tunnel defects and melting. The best appearance of the joint was obtained for the set of parameters of 925 rpm and 47.5 mm/min. The samples of the same joint were found to be of the highest mechanical properties—ultimate tensile strength (UTS) of 194 MPa and elongation (A) of 9.2%. The results were confirmed by the fractography analysis, which in this case indicated the ductile fracture mode. Dynamic plastic behaviour strongly depends on the process parameter values, which was reflected in the results of surface texture analysis. The parameter selection resulted in significant changes in the roughness results (from 8 to 14.2 µm depending on the sample) as well as the flow ring distance of the weld (from 20 to 50 µm depending on the sample). [ABSTRACT FROM AUTHOR]

This study reports new observations from the fabrication of high-aspect-ratio hollow tubes of SS410 through wire-arc directed energy deposition (wire-arc DED) process. Characterisation work was performed on a single tube as a function of its build height. The maximum ultimate tensile strength (UTS) of 1372 MPa and maximum yield strength (YS) of 980 MPa were achieved in the middle region of the tube. The highest UTS in the middle was attributed to the low delta ferrite content. The reduction of delta ferrite was found to be linked with the repetitive heating and cooling. In contrast, the top and bottom sections exhibit a substantial presence of delta ferrite, indicating that the cyclic effects were not considerable. Nevertheless, the presence of significant ductility in the bottom region of the component indicated the occurrence of tempering effects. This observation is further supported by the lower levels of local strain observed using KAM mapping. Overall, this work proposes a novel fabrication method for producing hollow sections with superior strength and ductile properties. [ABSTRACT FROM AUTHOR]

Electric pulse–assisted machining (EPAM) can improve the quality of the machined surface, lower the machining stress on the material, and increase the material's machinability. It offers a useful machining technique for working hard and difficult-to-machine metals with little plasticity. To account for this, this paper reviews experiments of EPAM using the electroplasticity effects (EPE) of metals and describes the use of electroplasticity in terms of plastic forming machining and cutting machining, and it also depicts the processes and benefits of EPAM. The experimental results show that the partial stress reduction during EPAM is up to 70%, the roughness is decreased by 40%, the work-hardening is reduced by 44%, and the material's machinability is partially improved. Various hypotheses have been pioneered by academics regarding the electroplasticity effect's mechanism, and they have all undergone experimental testing. Most academics today think that there are various mechanisms involved in electroplasticity, and that certain metals have various mechanistic effects. The paper gives theoretical suggestions for the use and further development of electroplasticity by summarizing the current processes of electroplasticity in terms of thermal and athermal effects. The thermal effect is the Joule heating effect. Other athermal effects include the electron wind effect, skin effect, pinch effect, magnetostrictive effect, de-pinning effect, and vibration effect. A summary diagram of the application and mechanism effects of EPE in processing is also included in the script. Finally, the article summarizes EPE, provides a constructive outlook on the future development of EPAM, and reveals the current problems. [ABSTRACT FROM AUTHOR]

Additive manufacturing (AM) technologies have transformed manufacturing, by providing greater control over material deposition and consumption. Thanks to greater customization and their high strength-to-mass ratio, the AM of composite materials has significantly grown over the past few years. The main focus in this research area is improving printing precision and higher production rates. However, there is a lack of thorough analysis on the energy consumption of fused filament fabrication (FFF) machines for composite manufacturing, especially when associated with mechanical and economic aspects. We designed an experimental method, based on flow analysis for measuring the impact of temperature parameters on total cost, energy consumption, and tensile resistance of composite parts made by FFF. The user should be able to improve FFF efficiency regarding economic, energy, and technical aspects and obtain recommendations for setting up and using the machine. This study confirms that combining traditional economic and technical indicators (total cost and tensile resistance) with emerging energy indicators (specific energy consumption) can be successfully applied to additive manufacturing to provide an overview of printing parameters impact. Results are yielding information to support optimization investigations depending on the need and goal. For example, two tested parameter combinations that offer similar tensile properties (4% reduction in tensile resistance compared to the best combination) show a 20% difference with lower energy consumption. [ABSTRACT FROM AUTHOR]

Additive manufacturing is a powerful process to build complex geometry. Besides the numerous process parameters influencing the mechanical part performances, other parameters related to the initial powder feedstock or component machining are of most importance. In this study, the combined effect of a wide particle size distribution, surface machining and stress-relief heat treatment on the microstructure and mechanical properties (tension and fatigue) of a stainless steel AISI 316L, produced by laser powder bed fusion, is investigated. In order to correctly investigate those parameters separately, the netshape/machined character of the sample, alongside with the heat treatment, is studied for two kinds of powder having different particle size distributions, i.e. narrow and widely spread. Results show that a large spread of particle size is only slightly detrimental to the fatigue life, in particular in high-cycle conditions due to a larger porosity related to a weakly more uneven particle spatial distribution in the bed. Nevertheless, this effect is of a second order compared to machining or heat treatments which greatly affect the mechanical behaviour. Surface machining and moderate heat treatment are then the best post-operational steps to increase the fatigue life in high-cycle fatigue conditions independently of the particle size distribution. Results are discussed in terms of defects, microstructural modifications, surface roughness, martensitic transformation and mechanical loading. [ABSTRACT FROM AUTHOR]

Abstract   : The fact that the weld geometry is vital in the cooling rate and determining the weld metal quality is obvious to all. So, the Taguchi technique was used to determine the process parameters of gas metal arc welding to access optimal weld bead geometry. In addition, this study investigated the effect of siliconized Zn-graphene oxide complex nanoparticles as one of the input parameters on the weld bead geometry, including the penetration depth, bead height, and bead width of the weld. Hence, the S/N and ANOVA statistical analyses were done to establish the relationship between the gas metal arc welding process's input parameters and output variables to achieve the weld bead with the highest penetration depth and the lowest bead height and width. The results showed that in the L00 sample compared to the L0 sample (sample without nanoparticles), in addition to having a very high penetration depth, the ultimate tensile strength, and yield strength have increased by 58.84% and 28.24%, respectively. [ABSTRACT FROM AUTHOR]