Ultimate Tensile Research Articles

Enhancing mechanical properties in Mg microtubes using tubular channel angular pressing-extrusion (TCAPE): A promising severe plastic deformation method

In this study, a novel method, Tubular Channel Angular Pressing-Extrusion (TCAPE), is introduced for manufacturing ultrafine microtubes. This method, integrating Tubular Channel Angular Pressing (TCAP) and microtube extrusion (MTE) processes, reduces the number of stages in the fabrication of ultrafine microtubes while achieving favorable mechanical properties. In the TCAPE process, the tube undergoes Severe Plastic Deformation (SPD) in the shaping region and is subsequently shaped into the desired geometric dimensions through the extrusion process at the end. To investigate the effect of the number of SPD passes on the microstructure and mechanical properties of the produced microtubes, one-pass and two-pass SPD were applied. Metallography, XRD testing, tensile testing, and hardness measurement were employed for analysis. For a one-pass SPD, the sample was processed only through the TCAPE process (TCAP + MTE), while for a two-pass SPD, the sample underwent the TCAP process first and then underwent TCAPE for the second processing step (2TCAP + MTE). Tensile test results indicate an increase in Ultimate Tensile Strength (UTS) from the initial value of 73 MPa–103.1 MPa and 148 MPa, and elongation altered from the initial value of 10 to 7.1 and 17.5 after two-pass SPD. Metallography results show a reduction in grain size from the initial value of 160 μm to 15 μm and 3 μm after two-pass SPD. The TCAPE process, due to applying higher strain (1.955) compared to the TCAP process (1.64), exhibits better performance in refining the microstructure and improving mechanical properties. The hardness and ultimate strength of the TCAPE-processed sample are 13.33% and 13.5% higher than those of the TCAP-processed sample, respectively.

Microstructure and properties of in situ Al2O3 particle-reinforced aluminium alloy lattice rods fabricated by wire-arc-directed energy deposition

Lattice structures have great potential for application in the thermal protection systems of high-performance hypersonic vehicles (Mach > 5). They are lightweight, highly load-bearing and provide good heat insulation. Wire-arc directed energy deposition (WA-DED) is an effective method for preparing lattice structures made from metal lattice rods. A method is proposed to improve the ultimate tensile and compressive strengths of aluminium (Al) alloy lattice rods and lattice structures made by WA-DED. The replacement reaction of Al and NiO generates Al2O3, which was used to improve an Al–Cu alloy (2xxx series). An Al–Cu–NiO system cored wire filled with NiO particles was developed as the raw material for studying WA-DED lattice rods. Then the rod was heat treatment. Tests show that the strength of in situ Al2O3-particle-reinforced Al alloy rods was 281 MPa, which is 13.9% higher than that of Al–Cu 2319 Al alloy deposited rods. Reinforcement also increased the elongation (EL) from 11.3% to 13.5%. Strength is increased by Al and NiO reacting in situ to form an Al2O3 phase with refined grains. Most of the generated Ni is dissolved in Al2Cu to form a nano γ-Al7Cu4Ni phase, which plays a second-phase strengthening role. After T6 heat treatment, the strength and EL of 2319-NiO-cored wire deposited rods was 441 MPa and 10.4%. Fine, needle-like θ’-Al2Cu structures and Al2O3 and γ-Al7Cu4Ni nanoparticles pin dislocations, prevent their movement and improve the mechanical properties of the rod. The compressive strength of a planar lattice structure after T6 heat treatment was 105 MPa and its weight was only 15 g, demonstrating high specific strength. Finally, arc additive manufacturing with the developed 2319-NiO-cored wire was used to fabricate a curved-generatrix-shell pyramid lattice structure for use in the thermal protection cone of a hypersonic vehicle. Its thermal insulation coefficient was 82.5%, demonstrating excellent insulation performance. This study provides insights into the manufacturing of thermal protection systems for lightweight, high-strength and high-heat hypersonic vehicles.

Additive manufacturing of WE43 and modified AZ91D magnesium alloys using the laser engineered net shaping process

Magnesium alloys WE43 and AZ91D offer weight savings for structural applications. WE43 contains rare-earth elements such as yttrium and neodymium, whereas AZ91D and the AZ class of alloys are lower-cost containing aluminium and zinc. This work uses a modified version of the latter, identified as AZ91D*, where calcium and yttrium have been added. Laser Engineered Net Shaping (LENS) equipment was used to investigate the 3D printing behaviour of gas-atomized WE43 and AZ91D* material. Process evaluations were first done using single track laser scans across wrought substrates of WE43 and AZ31. Process parameters were then developed that enabled deposition of build coupons with less than 1% porosity. These were used for microstructural and mechanical property assessments. The energy densities used were in the range of 40 – 60 J/mm² for AZ91D*, while for WE43 a value of 50 J/mm² was selected. A focus of the work was managing the tendency of magnesium materials to fume heavily during deposition, while achieving a deposit with close to nominal density, i.e. having a low incidence of voids or other micro- or macro-structural defects. The porosity of AZ91D* builds did not seem to correlate with increasing deposition energy density, however WE43 builds did, up to a practical limit imposed by generation of excessive fume. WE43 generated much less fume than AZ91D*. Analysis of the input powder materials indicate the presence of oxides on the particle surfaces. The WE43 powders had a noticeable shell of yttrium oxide. The microstructures of WE43 builds show the presence of arc-shaped structures that are likely the same yttrium oxides, partially, or fully ‘unfolded’. Tensile testing was conducted on WE43 build coupons to assess the effect of a T6 heat treatment. The effect on the ultimate tensile and yield strengths was negligible, however the % elongation at break almost doubled. Inspection of the fracture surfaces suggests this was due to a change in mechanism from fracture initiation at sites of lack-of-fusion/un-melted particles, to a more ductile micro-void coalescence. Furthermore, a not previously described microstructure anomaly was observed: the presence of pure elemental magnesium crystallites and films on the fracture surface. These are attributed to condensation of magnesium vapour on previously built layers and are a possible reason for the existence of lack-of-fusion defects. The in-depth study of process fundamentals will enable future work on process fume inhibition based on process optimization and alloy composition with the goal of producing parts for biomedical and lightweighting applications.

Process-Structure-Property Relationship Development in Large-Format Additive Manufacturing: Fiber Alignment and Ultimate Tensile Strength.

Parts made through additive manufacturing (AM) often exhibit mechanical anisotropy due to the time-based deposition of material and processing parameters. In polymer material extrusion (MEX), printed parts have weak points at layer interfaces, perpendicular to the direction of deposition. Poly(lactic acid) with chopped carbon fiber was printed on a large-format pellet printer at various extrusion rates with the same tool pathing to measure the fiber alignment with deposition via two methods and relate it to the ultimate tensile strength (UTS). Within a singular printed bead, an X-ray microscopy (XRM) scan was conducted to produce a reconstruction of the internal microstructure and 3D object data on the length and orientation of fibers. From the scan, discrete images were used in an image analysis technique to determine the fiber alignment to deposition without 3D object data on each fiber's size. Both the object method and the discrete image method showed a negative relationship between the extrusion rate and fiber alignment, with -34.64% and -53.43% alignment per extrusion multiplier, respectively, as the slopes of the linear regression. Tensile testing was conducted to determine the correlation between the fiber alignment and UTS. For all extrusion rates tested, as the extrusion multiplier increased, the percent difference in the UTS decreased, to a minimum of 8.12 ± 14.40%. The use of image analysis for the determination of the fiber alignment provides a possible method for relating the microstructure to the meso-property of AM parts, and the relationship between the microstructure and the properties establishes process-structure-property relationships for large-format AM.

Prospective cold metal working and analysis of deformation susceptibility of CuMg alloys with high magnesium content

Metal alloys designated for cold metal working exhibit much higher strength properties than pure materials due to solid-solution hardening. However, with the increase of mechanical properties its plasticity and workability decreases. Constant development and demand in this area has led to research on many copper alloys, such as copper alloys with high content of magnesium which were never tested before. The limitations regarding cold metal working of CuMg alloys is the main objective of this paper. Here we show that the tested materials exhibit much higher mechanical properties than currently used as electric conductors and carrying-conducting equipment materials such as pure copper, aluminum, M63 brass or CuNiSi alloy. The results were obtained using Hollomon relation, Considére criterion, Gubkin method and hardness measurements. It lead to assessing the prospective cold metal working of CuMg alloys with 2 wt% of magnesium up to 4 wt% of magnesium. The test range included upsetting with 10–50% of cold deformation. It provided the results on evolution of mechanical properties and deformability of tested alloys. Additional information was provided based on the alloys subjected to 50% of strain. The results have proven that as the amount of magnesium increased so did the assessed values, however, it was also linked with increasing friction coefficient. Measured hardness was 2 times higher and calculated Ultimate Tensile Strength (UTS) was even 2.5 times higher in reference to pure copper in the as-cast state. However, with magnesium content at 3.6 wt% or higher, the elevated amount of α + β phase causes brittleness making it impossible to subject these materials to cold metal working processes. We anticipate our assay to be a starting point for more sophisticated models and experimental research concerning cold metal working processes of CuMg alloys of high-strength, which may lead to developing novel and promising set of alloys.

In-situ mechanical and microstructural characterization of miniaturized Al-Mg-Sc-Zr and AlSi10Mg specimens processed by laser powder-bed fusion (PBF-LB)

Manufacturing through powder-bed fusion laser-beam (PBF-LB) enables innovative part design strategies, facilitating weight reduction, and capitalizing on the metallurgical conditions developed during the manufacturing of designed alloys. Consequently, Al-based light alloys hold enormous potential for reducing fuel consumption in the transport industry. Fabricating such small features has a significant impact on heat dissipation, thereby affecting microstructure, porosity, and, consequently, mechanical properties. This study proposes the use of near-net shape miniaturized tensile specimens in both horizontal and vertical orientations to characterize Al-Mg-Sc-Zr, commercially known as Scalmalloy®, and AlSi10Mg, two aluminum alloys typically employed in PBF-LB. The size and distribution of both grains and pores were analyzed and compared, with Al-Mg-Sc-Zr exhibiting a more competitive set of properties compared to AlSi10Mg. This difference also influences mechanical properties. Al-Mg-Sc-Zr demonstrated double the Ultimate Tensile Strength (UTS) of AlSi10Mg (450 MPa versus 225 MPa) and higher hardness values (142 HV30 versus 75 HV30), with similar elongation in both alloys (approximately 12–16%), owing to its fine microstructure and low porosity of the near-net shape miniaturized tensile specimens. Neither material exhibited any form of anisotropy. In-situ SEM tensile tests were conducted to monitor damage evolution, allowing continuous observation of crack nucleation and propagation through imperfections typically encountered in PBF-LB. Despite differences in static strength, the fracture surfaces of the samples displayed a ductile behavior in both materials.

Influence of defects formation on the cracking behavior of LPBFed Cu-Cr-Zr alloy: Micro-mechanism and CRITIC-WASPAS approach

Advanced strategies and techniques in the Laser Powder Bed Fusion (LPBF) process for printing Cu-Cr-Zr alloy must be created to overcome the major flaws such as cavity formation, unstable thermal capillary convection and thermodynamic instability. In this research, the significant process variables in the LPBF techniques such as Laser Power (LP) of 430, 500 and 570 W, Scanning Velocity (SV) of 550, 750 and 950 mm/s, Hatching Distance (HD) of 0.06, 0.08 and 0.10 mm were considered into account to fabricate a crack-free Cu alloy coupon with maximum Relative Density (RD), Ultimate Tensile Strength (UTS) and Reduced Elastic Modulus (REM). To optimize the process variables, a Criteria Importance Through Intercriteria Correlation (CRITIC) associated with the Weighted Aggregated Sum Product Assessment (WASPAS) approach was employed. Finally, the confirmation experiments were performed for the optimal settings (LP of 430 W, SV of 750 mm/s and HD of 0.06 mm) and the initial settings (LP of 570 W, SV of 550 mm/s and HD of 0.10 mm). The optimal settings show an 8.6 % enhancement in relative density of 99.82 %, which also reflects in 47 % improvement in UTS of 336 MPa and a 27.8 % enhancement in REM of 147.45 GPa compared with the initial settings. With the help of fracture morphology, the effect of defect development on the propagation of fractures on the printed coupons was also investigated. Moreover, the confirmation experiments aligned more with the CRITIC-integrated WASPAS approach.

Laser metal deposition of AlSi10Mg for aeroengine casing repair: Microhardness, wear and corrosion behavior

Laser metal deposition (LMD) based remanufacturing leverage of the flexibility of additive manufacturing and provides an attractive and cost-effective means for repairing or remanufacturing high value engineering components. In this work, AlSi10Mg alloy was cladding on the surface of cast aluminum alloy plate for aeroengine casing, AlSi10Mg repair layer with porosity of only 0.19% was obtained when the laser power P = 1800 W, powder feeding rate f = 1.6 g/min, scanning speed v = 8 mm/s. Microhardness, wear and corrosion resistance tests were used to evaluate the repair feasibility of the AlSi10Mg repair layer. The results indicated that the microhardness of the AlSi10Mg repair layer was more than 80% of aeroengine casing, the ultimate tensile strengthen and elongation of the repair layer are 215 ± 12 MPa and 5.79 ± 0.1%, respectively, while the tensile strength of the substrate is 225 MPa. The mechanical properties of the repair layer basically meet the repair requirements of the aeroengine casing. The coefficient of friction (COF) and wear rate ω of the repair layer were comparable to the level of aeroengine casing. Moreover, the corrosion behavior test results showed that the corrosion potential of as-build AlSi10Mg repair layer was −0.90 V, which was higher than that of substrate (−0.92 V), indicating that the AlSi10Mg repair layer has better corrosion resistance than substrate, and the Al9Si phase is the important factor that effecting the corrosion performance of AlSi10Mg repair layer. This work can provide reference for the potential application of the LMD technology in the field of high-quality repair of aeroengine casing.

Improving the Industrial Efficiency of Recycling Aluminum Alloy Chips Using Friction Stir Extrusion: Thin Wires Production Process

Friction stir extrusion is one of the most promising solid-state chip recycling techniques because of its relative simplicity and high efficiency. One of the most straightforward applications for the process is the production of recycled wires to be utilized as filler material in welding or welding-based additive manufacturing processes, in order to create an industrial symbiosis link, fostering a circular economy and enhancing the technology readiness level of the process. The scalability of the process to the thin wires needed for such applications has not been investigated so far. In this paper, an experimental and numerical analysis was developed. A dedicated numerical model was first validated and then used to design the tool geometry. The effect of tool rotation and tool force on both “standard” mechanical properties, as Ultimate Tensile Strength and microhardness, and specific properties for the envisaged application, as the wrapping around reels with different radii, was investigated. The numerical model results were used to explain the influence of the process parameters on the material flow as well as on the distribution of the primary field variables, namely temperature, strain, and strain rate. Finally, the energy demand was measured, and the specific energy consumption (SEC) was evaluated. It was found that a conical shoulder surface favors the conditions for effective solid bonding. Low values of the extrusion force have detrimental effects on the wires properties as they result either in insufficient strain, or hot cracking defects. High values of extrusion force results in lower SEC, unlocking the potential of the process as symbiotic link enabler.

Ironing process optimization for enhanced properties in material extrusion technology using Box–Behnken Design

Material Extrusion (MEX) technology, a prominent process in the field of additive manufacturing (AM), has witnessed significant growth in recent years. The continuous quest for enhanced material properties and refined surface quality has led to the exploration of post-processing techniques. In this study, we delve into the ironing process as a vital processing step, focusing on the optimization of its parameters through the application of Design of Experiments (DoE), specifically the Box–Behnken Design (BBD). Through a systematic examination of ironing process parameters, we identified optimal conditions that resulted in a substantial reduction in surface roughness (Ra) by approximately 69%. Moreover, the integration of optimized ironing process parameters led to remarkable improvements in mechanical properties. For instance, the Ultimate Tensile Strength (UTS) saw a substantial improvement of approximately 29%, while the compressive strength (CS) showed an increase of about 25%. The flexural strength (FS) witnessed a notable enhancement of around 35%, and the impact strength (IS) experienced a significant boost of about 162%. The introduction of ironing minimizes voids, enhances layer bonding, and reduces surface irregularities, resulting in components that not only exhibit exceptional mechanical performance but also possess refined aesthetics. This research sheds light on the transformative potential of precision experimentation, post-processing techniques, and statistical methodologies in advancing Material Extrusion technology. The findings offer practical implications for industries requiring high-performance components with structural integrity and aesthetic appeal.

A comparative analysis between backpropagation and general regression neural networks to predict the tensile properties of fused filament fabricated parts

The Fused Filament Fabrication (FFF) process comprises a large number of process parameters that affect the resultant mechanical properties of the parts, generating uncertainties during the Design for Additive Manufacturing (DfAM) practice. Several studies have used Artificial Neural Networks (ANN) based on classification machine learning techniques such as Backpropagation Neural Network (BPNN), to evaluate the dimensional accuracy, surface roughness, compressive, flexural and tensile strength of FFF parts. As an alternative, in this paper a new General Regression Neural Network (GRNN) approach, based on a regression machine learning technique, is proposed to estimate the tensile structural properties of polylactic acid (PLA)-FFF parts using variable process parameters. The performance of the new proposed GRNN is compared with the performance of a BPNN. The comparison and evaluation are based on their capability to accurately predict the experimental Ultimate Tensile Stress (UTS) and the Elastic Modulus ( E) of FFF parts. The outcomes of this evaluation have shown that although the GRNN and the BPNN are able to estimate with high accuracy the structural behaviour of FFF parts, the performance of the proposed GRNN is superior (0.001 Mean Square Error, MSE) than the BPNN (0.0031 MSE). Moreover, the new proposed GRNN fits the experimental test values with a minimal average error of 0.62%. Thus, the proposed GRNN can be used during the design of components intended to be manufacture by FFF.

Study the effects of TiB2 reinforcement on the AA-2014 matrix fabricated by friction stir processing

This study explores the impact of TiB2 nanoparticles on the microstructure, microhardness, and tensile properties of AA-2014 surface composite manufactured through Friction Stir Processing (FSP). A series of experiments were conducted with varying FSP parameters, and the findings were compared with the base metal. Microstructure studies revealed optimal bonding between TiB2 and the AA-2014 substrate at 1200 rpm, surpassing results from 900 and 1600 rpm. However, microstructural analysis unveiled agglomeration of particles and void formation on the composite surface. Microhardness values indicated a substantial increase from 88 HV (AA-2014) to 138 HV (AA-2014/3%TiB2 @1200rpm), attributed to the presence of TiB2 nanoparticles and FSP-induced modifications. Ultimate Tensile Strength (UTS) values exhibited a noteworthy improvement from 290 MPa (AA-2014) to 465 MPa (AA-2014/3%TiB2 @1200rpm), emphasizing the positive influence of uniform TiB2 dispersion achieved during FSP. The study underscores the effectiveness of TiB2 reinforcement and FSP in enhancing the mechanical properties of AA-2014 surface composite, despite observed microstructural features.

Influence of laser power on mechanical properties of FGM of SS316L and IN625 fabricated by direct metal deposition

Direct Metal Deposition (DMD) is a metal Additive Manufacturing (AM) process. It is used for producing sustainability Functionally Graded Materials (FGM) and repairing of sophisticated parts. In this present research, a commercially available DMD machine deposited three partial FGM blocks of size 26 mm wide × 34 mm thick × 32 mm heights. The commonly influence parameters on Ultimate Tensile Strength (UTS) are scan velocity and laser power. The powders used for deposition were Stainless Steel 316L (SS316L), Inconel 625 (IN625), and their three different compositions. ASTM E8 tensile samples were cut from those blocks by wire cut-EDM. Micro-tensile tests were carried out on ASTM E8 samples using a SHIMADZU micro-tensile machine. The results revealed that partial FGM sample-2 had high sustainability UTS of 532 MPa as compared to remaining two samples. It is illustrated that for joining two dissimilar materials to obtain high UTS thick layered (i.e., thickness more than 1 mm) gradient path method should be selected at the medium laser power available on the DMD machine. However, the sample-3 has higher hardness at high laser power.

Investigating parametric effects during TIG welding of dissimilar metals

This paper explores the optimization of Tungsten-Inert-Gas (TIG) welding process parameters for creating a hybrid structure of Aluminium 6061 and Stainless Steel 304 using a copper filler rod (ER-Cu). The Welding of these two materials has industrial relevance owing to its weight reduction capabilities and environmental benefits. However, Aluminium and Stainless-Steel have different melting points and thermal properties. Aluminium has twice coefficient of thermal expansion and six times coefficient of thermal conductance as compared to Stainless-Steel. This difference often results in residual stresses and brittle intermetallic compounds in the weld region. We have chosen the Welding Current, Welding Speed, and Gas Flow Rate as input parameters, and Ultimate Tensile Strength (UTS) and Micro-hardness as response parameters. We have employed the Response Surface Methodology (RSM) using a Box-Behnken design to evaluate the influence of input parameters on UTS and Micro-hardness. Furthermore, an Analysis of Variance (ANOVA) is conducted to determine the input parameters' significance on the response parameters. Our surface plots demonstrate that UTS improves with increased Welding Current and reduced Welding Speed. Simultaneously, Micro-hardness increases with elevated Welding Speed and decreased current, up to a specific limit. The peak value of UTS (79 MPa) was observed with a Current range of 85-90 A, Speed range of 95-100 mm/min, and Gas Flow Rate of 14.5-15 l/min. On the other hand, maximum Micro-hardness (260HV) was obtained with a Current range of 80-85 A, Speed range of 105-110 mm/min, and Gas Flow Rate of 14.5-15 l/min. This research contributes to improving the manufacturing process of hybrid structures, specifically by optimizing the advantages of both Aluminium and Stainless Steel while addressing the challenges that arise during their combination. The study's conclusions have major consequences for sectors looking to take advantage on the mutually beneficial characteristics of different metals in welding applications.

Optimization of stir casting parameters for the tensile behavior of nano Al2O3 and ZrO2 reinforced Al-Mg-Si alloy metal composites

Stir casting is a frequently used method in the metallurgical process of casting aluminium composites. The microstructure and performance of the composites are influenced by the stirring casting parameters. The majority of research conducted in this area focused on producing composites using stir casting parameters that were predetermined, without utilizing an optimization method. This work aims to optimize the stir casting parameters for the manufacturing of Al-Mg-Si (Al6061) alloy reinforced with hybrid nano Al2O3 and nano ZrO2 in order to enhance its performance. The Taguchi optimization technique was employed to analyze the important effects of stir casting parameters on the ultimate tensile strength of a hybrid metal matrix composite. The composites were produced by the ultrasonic aided stir casting method, employing a set of process parameters determined by the Taguchi L16 orthogonal array. The S/N (Signal to Noise ratio) and Regression model were utilized to determine the optimal values and assess the influence of process parameters on the tensile qualities. The Minitab 21 software was utilized to perform simultaneous optimization of the attributes. The findings indicated that the composition of the nano reinforcement, stirring temperature, stirring speed, and stirring time all had a substantial impact on improving the UTS (Ultimate Tensile Strength) of the material.

Effect of the individual layer thickness and relative blanking clearance on micro-blanking for Cu/Nb multilayer composite sheets

In this study, two types of Cu/Nb multilayer composite sheets with individual layer thicknesses of 11.11 μm and 0.35 μm, respectively, were first prepared and then tested by micro-blanking. The results show that the sheets of 0.35 μm exhibit higher ultimate tensile and shear strengths, and greater elongation, compared to those with an individual layer thickness of 11.11 μm. The sheet with an individual layer thickness of 11.11 μm achieves optimal blanking accuracy at a relative blanking clearance of 7%. Additionally, when the relative blanking clearance is 3%, it exhibits a significant proportion of smooth areas on the shear surface. Investigation of the shear surface at different ratios of punch stroke to sheet thickness (h/t) reveals that the Cu/Nb multilayer composite sheet experiences significant extrusion and bending during the micro-blanking process. Furthermore, the laminated structure exhibits remarkable continuity and deformation mobility, delaying crack formation. This study provides theoretical support for the plastic micro-blanking technology of multilayer composite.

Fatigue and anisotropic behavior of wire-arc additive manufactured TC17 titanium alloy

Wire-arc additive manufacturing (WAAM) was used in aeronautical engineering due to its low equipment cost and ability to create complex shapes. However, the fatigue behavior of WAAM titanium alloy, specifically for low cycle fatigue (LCF), was poorly studied. This paper investigated the microstructure and mechanical behavior of WAAM TC17 in both vertical and horizontal orientations. Fully reversed LCF tests were conducted on specimens with varying strain amplitudes from ±0.4 % to ±1.2 %. The results found that the ultimate tensile and yield strength were similar for both vertical and horizontal samples, but the elongation in the horizontal orientation was approximately 60 % lower than that in the vertical orientation. Considering the cyclic loading behavior, both vertical and horizontal samples exhibited cyclic softening characteristics at high strain amplitudes (0.8%–1.2 %). Additionally, the cyclic softening rate (CSR) of horizontal samples exhibited a higher than that of vertical samples at high strain amplitude. The LCF cracks of WAAM TC17 were initiated from the surface and internal defects of the samples. The LCF performance of the horizontal samples was found to decrease than that of vertical samples. Specifically, the fatigue performance of the horizontal samples is lower by 36.7 % compared to the vertical samples when the number of cycles is 103.

Non-destructive estimation of mechanical properties in Usibor® 1500 via thermal diffusivity measurements: A thermographic procedure

The study investigated the anti-correlation between thermal diffusivity and Ultimate Tensile Strength (UTS) in Usibor® 1500 steel. The non-destructive pulsed laser spot thermography technique was used to analyze fifteen boron steel specimens with varying bainite/martensite phase percentages, while the UTS was measured through uniaxial tensile tests. A 23 % thermal diffusivity difference was found between fully martensitic and fully bainitic structures, with UTS varying by around 90 %. The strong anti-correlation was confirmed (Spearman coefficient −0.98) and an empirical power-law equation was derived to estimate UTS based on thermal diffusivity variations. The approach showed an R-squared value over 0.84, providing a non-destructive thermographic procedure for UTS estimation in Usibor® 1500 steel, offering valuable material property insights.

Analysis of the Influence of Structural Characteristics on the Tensile Properties of Fused Filament Fabricated ABS Polymer Using Central Composite Design

This study presents an investigation of the effects of structural characteristics, such as the layer height, infill density, top/bottom layer line directions and infill pattern, on the structural efficiency of Acrylonitrile Butadiene Styrene (ABS)-based specimens. The Fused Filament Fabrication (FFF) technique was utilized for the specimen fabrication, and the Ultimate Tensile Strength (UTS) and Strength-to-Mass (S/M) ratio were examined. The tests were planned according to the Central Composite Design (CCD), and an empirical model for each response was developed, with respect to the applied factors and their interactions. The analysis revealed that the characteristics with the strongest influence on the UTS and the S/M ratio were the infill and the layer height, respectively. Moreover, it was observed that the honeycomb structure contributed to the highest UTS compared to the other patterns. Finally, an optimization analysis based on the desirability function was performed, highlighting the combination of a 0.3 mm layer, 21.81% and 76.36% infill, 0° direction and the honeycomb pattern as the optimal for maximizing both UTS and S/M ratio under different desirability.

Effect of martensitic phase formation on the nano-mechanical attributes during the electron beam melting process of Ti-6Al-4V

Electron Beam Melting based Ti-6Al-4V parts plays a predominant role in the field of bio medical and aerospace applications, especially in the aero due to its sustainability. However, there were not enough studies on nano-mechanical properties that looked at how phase changes during the heat and cooling process affected the printing process. With the assistance of OM and FESEM with EDX, the EBM Ti64 coupons were analysed for the grain orientation and phase transformation studies. The FESEM with EDX supported the existence of columnar grains and orthogonally oriented martensitic needles. Additionally, both XRD and TEM confirmed the presence of vanadium-rich precipitates and the HCP α-Ti and BCC β-Ti phases. EBSD analysis was adopted to further investigate the orientation of grains. The nano-hardness and elastic reduced modulus mapping confirmed the phase transformation to martensitic phase. The strong “martensitic” phase had a maximum reduced modulus of 183.5 GPa and a hardness value of 7.31 GPa. However, the EBM based Ti64 possesses an average nano-hardness and reduced modulus of 4.26 GPa and 118.3 GPa under the applied load of 2500μN. In addition, topographic wear and scratch tracks confirmed the soft nature of α colonies by forming more piles of materials, while nano-wear and scratch analysis predicted the functions caused by the presence of hard martensitic phases. The SR sensitivity of the Ti64 specimens was investigated using three different quasi-static strain rates. It was determined that the EBM Ti64 parts have a considerable effect over the strain rate, whereas, a quasi-static strain rate allowed for the achievement of the highest possible Ultimate Tensile Strength (UTS) and ductility.