Band 66, Heft 1

Approximately 24 out of every 100 adults in the United States, or 58.5 million people, have arthritis, which refers to a condition that causes pain and inflammation in a joint according to US National Center for Chronic Disease Prevention and Health Promotion. Osteoarthritis is the most common type of arthritis, and it may damage almost any joint but mainly occur in hands, hips and knees. While there are several joint replacement options for hips and knees, there are only limited options for finger joints. In this paper, we report on several aspects of testing of novel finger joints: testing apparatus design, cadaveric performance test and material testing results of titanium joints using 3D-printed Ti6Al4V extra low interstitial (ELI). Soft cadaveric hands with finger joints were surgically replaced by additively manufactured titanium joints following the exact same anatomy of the cadavers. These small joints were engineered to mimic the biological and natural movements of fingers. The apparatus, methodology and results of biomechanical tests were deployed to evaluate and validate the joints particularly those of titanium joints manufactured via laser powder bed fusion methods (PBF-L/M).

In this work, resistance spot weldability of dissimilar TWIP1000/TRIP800 joint was investigated in terms of microstructural and mechanical characterization. The maximum tensile-shear load bearing capacity was 16,918 N in 6 kA welding current with 30 cycles of welding duration. Pull-out failure which was dominant and interfacial failure modes were obtained in tensile-shear tests. Although heat affected zone of the TRIP steel was totally transformed into tempered martensite, it showed better separation performance than TWIP steel. Heat affected zone of the TWIP steel was narrow, secondary phase formations and sudden grain coarsening have compromised the weakest point in the resistance spot welded joint.

The work entailed the influence of particle size on the characteristics and water absorption resistance of avocado pear wood fiber/low-density polyethylene (APWF/LDPE) composite enhanced by pretreatment. The fiber particle of 100, 80, 60, 40, and 20 mesh (150, 180, 250, 425, and 850 µm) for the avocado wood fiber (APWF) was infused in the resin. Each particle of the fiber with fiber content of 5–25 wt% for the untreated, pretreated with NaOH, NaOH + CH 3 COOH, and NaOH + CH 3 COOH + MAPE was intermixed in the resin to produce the APWF/LDPE composites, respectively. The APWF/LDPE composites were analyzed on the properties, water absorption resistance, Fourier transform infra-red, and scanning electron microscopy. The study exhibited that mechanical properties and water absorption resistance of the APWF/LDPE composite were improved at lower particle of the fiber triggered by treatment. The best properties were confirmed at 150 µm of APWF pretreated with NaOH + CH 3 COOH + MAPE when compounded with the resin. These were proportional to 15.92 MPa, 0.867 GPa, 41.39 MPa, 0.662 GPa, 683 Pa, 84.04 kJ m −2 , and 2.44 % for tensile strength, elastic modulus, flexural strength, bending modulus, Brinell hardness, impact strength, and water absorption resistance, respectively. The APWF/LDPE composite for NaOH + CH 3 COOH + MAPE pretreated is recommended for interior cabinet of an automobile.

B-pillars are vital structural components in rollover-related accidents. In this study, the performances of homogeneous B-pillars designed from B1500HS-T25, AA2024-T351, and AA6061-T6 materials and hybrid B-pillars designed from their combinations under crushing load were compared in energy absorption using simulation results. Optimization studies were conducted utilizing the upper part B1500HS-T25 and lower part AA6061-T6 hybrid B-pillar, which gave the highest energy absorption value. Method of feasible directions was utilized to solve the single-objective optimization, and B-pillar mass decreased by 22.6 % from 2.736 to 2.117 kg compared with the reference B-pillar. Global Response Search Method and Multi-Objective Genetic Algorithm were used to solve the multi-objective optimization problem. B-pillar with min mass decreased mass value by 25 % from 2.736 to 2.052 kg for both methods. This optimum hybrid B-pillar can be utilized in car design.

In this research work, we subjected the Sleipner steel to pack-boronizing within the temperature range of 1173–1323 K, lasting from 1 to 10 h. Our study involved assessing the steel’s microstructure by examining interphase morphology and measuring the layers’ thicknesses through scanning electron microscopy. To determine the phase composition of the boronized layers, we employed X-ray diffraction analysis. Furthermore, we investigated the redistribution of certain elements during the boronizing process using EDS mapping and EDS point analysis. The boride layers were found to consist of FeB and Fe 2 B phases. We conducted microhardness testing using the Vickers method on the diffusion zone, Fe 2 B, and FeB. Lastly, we utilized a diffusion model to evaluate the activation energies of boron in FeB and Fe 2 B, and we presented the results in terms of activation energies.

Tri-chiral structures are auxetic structures that show negative Poisson’s ratio. This effect is due to their microstructure and geometric sequence. They are used in the development of novel products as they show improved damping and energy absorption properties. While traditional manufacturing methods remain dysfunctional, the development of additive manufacturing technology provides opportunities for new studies in various industries such as aviation, textile, and automotive. In this study, passive airfoil morphing application was applied and a comparative study was carried out. A two-stage study was conducted. First, the tri-chiral pattern was fabricated by an FDM 3D printer with PLA+ and subjected to the in-plane compression test. Stress–strain curves of the tri-chiral structure were generated. Then, it was used in airfoil morphing applications. Morphed airfoil was also manufactured and a compression test was applied. Secondly, the aerostatic loads of the aircraft were calculated. Both conventional and chiral morphed ribs’ behaviors under flight loads were examined using the FEM and results were compared. The weight difference was calculated. In addition, eigenfrequency and eigenvectors of traditional and chiral ribs were computed and transverse vibration frequencies were expressed. Despite being more than 50 % lighter, chiral morphed rib was found to be stiffer than conventional rib.

In wood science and technology, researchers increasingly focus on the additive manufacturing in different aspects through assembly, mechanical, and physical characterization of the printed parts. One of the main parameters influence the wood features is the inhomogeneity of cellular structure. The effect of dislocation on the compression behavior was evaluated over the wood-inspired cellular structure. The 4.4 × 4.4 mm cross-cut–sized cell (0.8 mm cell wall thickness and 2.8 mm lumen diameter) with 10 mm thickness was arrayed by 6 columns and 3 rows to design the control model. The middle row was 0.8, 1.6, and 2.4 mm dislocated to obtain irregular models. Objects were fabricated through the deposition of acrylonitrile butadiene styrene filament using DaVinci 1.0 all in one three-dimensional printer. The effect of printing orientation (vertical and horizontal) on compression behavior was also figured out. The compression test was performed to obtain the load–deformation behavior of samples. According to the results, the horizontally printed samples presented better performance. Furthermore, horizontal alignment, rectilinear infill type, 90 % infill density, and 0.2 mm layer height combination presented the highest (5719 N) load-carrying capacity. The statistical analysis (P < 0.05) figured out that cell dislocation has significant influences on mechanical properties.

This study employs a high-energy-density gas tungsten arc welding (GTAW) process to fabricate a surface coating on a substrate of 0.15 percent carbon steel, incorporating powders of FeCr, FeMn, FeB, and graphite. The investigation encompasses a multifaceted approach, utilizing X-ray diffraction (XRD), optical micrograph (OM) analysis, energy-dispersive X-ray analysis (EDS), scanning electron microscopy (SEM) imaging, microhardness testing, and adhesive wear testing, with the aim of examining the composite coating’s microstructural attributes, microhardness, and performance under dry-sliding wear conditions. The research findings reveal the formation of diverse carbides and borides, including Mn 5 C 2 , Fe 3 C, B 8 C, B 4 C, Fe 3 B, Fe 7 C 3 , FeB, and MnB on the coated surfaces. Notably, the graphite particles within the FeB–FeMn–FeCr–C composite TIG welding coatings exhibit a range of morphologies, varying from sheet-like to dendritic structures.

In this study, the wear behavior of AA7075 alloy produced by thixocasting was investigated. The wear behavior of the AA7075 alloy is examined for three cases: extruded with T6 heat treatment, as-thixocast, and thixocast with T6 conditions. The dry sliding wear test was conducted with a tribometer according to ASTM G-99 standard. The microstructures were characterized by optical microscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDX). The tensile and hardness tests were performed to evaluate the mechanical properties. The AA7075 alloy was successfully shaped by thixocasting. The as-thixocast sample exhibited typical globular structures with multinary eutectic structures along the grain boundaries. The globular grains transform into a polygonal structure, and the grain size increases from 50 μm to 60 μm in the thixocast + T6 sample. This microstructure exhibited excellent wear resistance under dry sliding conditions in the thixocast + T6 sample. The aging treatment with prolonged solution process improved the mechanical properties two times and the wear rate three times for the thixocast AA7075 alloy. Furthermore, the thixocast + T6 sample exhibited a significant decrease in the coefficient of friction with the lowest wear rate compared to the as-thixocast sample. The dominant wear mechanisms are microdelamination, adhesion, and oxidation in all samples.

In this study, the effect of compaction pressure on the properties of AISI 316L and its machining performance was evaluated. AISI 316L powders were subjected to three different compaction pressures (550, 650, and 750 MPa). Subsequently, the samples were sintered in an argon atmosphere at a constant temperature of 1523.15 K. The microstructure, hardness, and mechanical properties of the materials were investigated. To examine the effect of compaction pressure on drilling characteristics (thrust force, torque, surface roughness, chip formation, and burr formation), the samples were subjected to dry drilling at different feed rates and cutting speeds. It was observed that increasing the compaction pressure resulted in smaller grain sizes in the microstructure, increased hardness, and higher tensile strength. Higher compaction pressure led to higher thrust force and torque, whereas lower compaction pressure resulted in improved hole surface quality and shorter chips. Additionally, at higher cutting speeds, the color of the chips changed due to the elevated temperatures associated with increased cutting speeds.

They are produced with the desired performance with friction modifiers, reinforcements, lubricants, binders, and fillers used in various properties in brake pads. This study investigated the effect of the use of halloysite nanoclay material used in different sectors as a filler in brake pads. The hot-pressing method produced brake pad samples containing 10–15 % and 20 % halloysite nanoclay. A full-scale brake pad tester determined the samples’ friction coefficient and wear rates. Scanning electron microscopy (SEM) and 3D profilometer analyses were performed on the worn sample surfaces after the experiment. As a result, it was determined that the halloysite nanoclay samples met the desired brake lining properties.

In this study, an LM13 metal-matrix composite was fabricated using two reinforcement particles (hard and soft) of titanium diboride and zirconium carbide. An experimental design was used to narrow down the trials. The significance of the model was tested using Student’s t -test and p values. The response surface statistical method was used to obtain the optimum process parameters for the high-strength hybrid metal matrix composite. From the experimental results, a maximum strength of 209 MPa was gained at a stirrer speed of 700 rpm, weight fraction of TiB 2 and ZrC of 9 %, and casting temperature of 675 °C. The ANOVA results showed that TiB 2 was the main influential process parameter, followed by the stirrer speed, casting temperature, and zirconium boride. The microstructure showed a fine and uniform distribution of reinforcement particles in the LM13 matrix. The fracture surface exhibited a mixed fracture pattern, which was due to the good bonding between the reinforcement and matrix at the interface.

The main objective of this study is to investigate the effect of gas metal arc welding (GMAW) and cold metal transfer arc welding (CMTAW) processes on microstructure and mechanical properties of AA8011-H18 aluminum alloy joints. The AA8011-H18 alloy sheets of thickness 3 mm were welded in butt joint configuration using conventional GMAW and CMTAW processes. The optical microscopy was employed for analyzing the microstructure of weld metal (WM) and heat-affected zone (HAZ) of the developed joints. The tensile properties and hardness of welded joints were evaluated using universal testing machine (UTM) and Vickers microhardness testing machine. The GMAW and CMTAW joints disclosed the joint efficiency of 58.33 % and 75.98 %, respectively. The CMTAW joints showed 30.25 % and 27.28 % improvement in tensile and yield strength compared to GMAW joints. However, there is a loss of 20 % ductility in CMTAW joints compared to GMAW joints. The superior tensile strength of CMTAW joints is correlated to microstructural refinement of WM and reduced grain growth in HAZ. It alludes to the wire retraction mechanism, which help to regulate the droplet transfer and lower the heat input.

The essence on sheet metal industry innovation for making light weight bodies has been increasing day-to-day in the automotive sector. Based on the current demand and significance of sheet metals, the present work has been carried out on AA5052-PVC-AA5052 sandwich sheets to find out its tensile behaviour and hence related mechanical properties. The tensile behaviours of as received AA5052 alloy sheet of 1 mm thickness, PVC sheet of 0.5 mm thickness and AA5052-PVC-AA5052 sandwich sheet of 2.5 mm thickness were investigated. From the test results, the mechanical properties like yield strength (YS), ultimate tensile strength (UTS), uniform elongation (UE), total elongation (TE), strain hardening exponent ( n ) and material strength coefficient ( K ) were evaluated. From the experimental results, rolling direction of base metal AA5052 alloy sheet has an influence on the mechanical properties; moreover, among three rolling directions such as 0°, 45° and 90°, better mechanical properties have been observed in 90° rolling direction. Similar tendency is seen in the case of sandwich sheets of 90°-P-90° rolling direction than other sandwich sheets. From this work, one can understand the improvement of mechanical properties with different combinations and rolling directions of AA5052 alloy sheet. The manufacturing industry can use these data as it is for their inclusion to the future products.