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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]

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]

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]

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 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]

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]

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]

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]

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]

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]