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Polyoxymethylene (POM) fiber is a new type of reinforcement material developed in recent years, which provides a new way and choice for the modification and reinforcement of cement-based materials. In order to improve the application of POM in the construction field, fiber-reinforced cementitious materials were prepared using 6- and 12-mm POM fibers. The effects of at two lengths of POM fibers on fluidity, compressive strength, flexural strength, flexural toughness, and tensile strength of cement mortar were investigated, and the bonding interface between fibers and the cement mortar matrix was observed using scanning electron microscopy (SEM). The results show that the addition of POM fibers reduced the fluidity and 7-day compressive strength of cementitious composites, but had little effect on 28-day compressive strength. With the increase of POM fiber volume fraction and length, better flexural toughness and ultimate tensile strength can be obtained. When the POM fiber length was 12 mm and the volume fraction was 0.90%, the equivalent flexural strength and ultimate tensile strength of the POM fiber–reinforced cement-based composite (POM-FRCC) increased by 46.3% and 13.5%, respectively, compared with the control group. Microscopic analysis revealed that the POM fibers were tightly bonded to the cement mortar matrix, and the fibers had a severe surface scraping in the resistance to damage. [ABSTRACT FROM AUTHOR]

This work focused on improving the weld quality and productivity of dissimilar friction stir welding of AA 7075-T6 and AA 2024-T3 aluminium alloys by controlling the process parameters of tool axial force, welding speed, tool offset, and rotational speed. A newly developed hybrid pentagonal tool is used for the fabrication of welds to enhance productivity. In this study, an RSM based on a central composite method is used for the design of experiments, optimisation, and data analysis. The result found that the ideal range of welding process parameters for 6-mm-thick AA7075-T6 and AA2024-T3 aluminium alloys by friction stir welding is to use a tool spindle rotational speed of 1178.51 rpm, an axial load of 7.78 KN, a traverse speed of 132.74 mm/min, and 0.958 mm tool offset towards the AA2024-T3 material side. Based on the UTS, a joint efficiency of 67.19% is achieved. It is observed that while increasing the value of FSW parameters like tool spindle rotational speed and traverse speed, the tensile strength and elongation values tend to increase drastically after further increasing those parameters, UTS and TE seem to decrease. [ABSTRACT FROM AUTHOR]

Artificial Intelligence algorithms based on the machine learning approach finds application in manufacturing and materials industries for the prediction and optimization of mechanical and microstructure properties. In the present study, six supervised machine learning regression-based algorithms i.e., Decision Trees, XGBoost, Artificial Neural networks, Random Forests, Gradient Boosting, and AdaBoost are used for the prediction of the Ultimate Tensile Strength of the Friction Stir Welded magnesium joints. Magnesium alloy type (AM20, AZ61A, AZ31B, and AZ31), Plunge Depth (mm), Shoulder Diameter (mm), Tool Traverse Speed (mm/min), Pin Diameter (mm), Axial Force (kN), and Tool Rotational Speed (RPM) are the input parameters while the Ultimate Tensile Strength (MPa) of the Friction Stir Welded joints is an output parameter. The results showed that the Magnesium Alloy type has the highest feature importance in comparison to other input parameters. It is also observed that the XGBoost algorithms yield highest coefficient of determination of 0.81. [ABSTRACT FROM AUTHOR]

Aluminium matrix composites (AMCs) play a vital role in constructing aircraft, marine and automobile components. The major issue in manufacturing of AMCs through stir casting method is a localized ceramic particles agglomeration. In current research, metal castings have been prepared with 97.5 wt% of aluminium alloy (AA 7075) and 2.5 wt% of nano-alumina (n-Al2O3) particles through a modified matrix encapsulated feeding technique. The tensile strength, microhardness and dry sliding wear behaviour of n-Al2O3 reinforced AA 7075 composites were measured following ASTM standards. The ultimate tensile strength of the developed AMCs varies from 280 to 315 MPa, which is 12.5% higher than unreinforced AA 7075 alloy. Yield strength increases from 140 to 158 MPa, whereas microhardness of the composites increases from 138 to 210HV. Due to homogeneous distribution of n-Al2O3, the overall wear resistance of n-Al2O3 reinforced AA 7075 composites increases up to 90% as compared to unreinforced AA 7075 alloy. Also, the addition of n-Al2O3 particles marginally reduces the network of microcracks and deep furrows in the worn surface. The microstructural and elemental studies are also performed through scanning electron microscopy and X-ray diffraction. [ABSTRACT FROM AUTHOR]

In this work, a novel microstructure-informed machine learning (MIML) framework is proposed for the longitudinal ultimate tensile strength (UTS) evaluation and the construction of microstructure-property linkages of titanium matrix composites (TMCs). The main components of the MIML framework include (i) high-fidelity simulation and dataset generation using finite element method (FEM), (ii) the quantitative characterization of microstructures obtained by 2-point cross-correlation analysis and principal component analysis, (iii) the extraction of structure-property linkages based on support vector regression model and (iv) the validation of MIML by experimental data. The fiber breakage observed by advanced microstructure characterization is considered as the dominant failure mode during mechanical tests of TMCs, which is embedded in the FEM simulations. The MIML approach reaches capable accuracy in UTS prediction of TMCs using FEM-generated datasets and trained MIML is validated by experimental data. In addition, the permutation importance-based method is utilized to accurately identify the key feature parameters related to UTS. The first two principal components of microstructural reduced-order representation are recognized as highly relevant features for UTS. The well-trained MIML model is a promising tool in the evaluation of the mechanical property, and further provides a technical chain for the establishment of microstructure-property linkages of multi-phase composites.

The ultimate tensile strength (UTS) of gray cast iron (GCI) can be affected by numerous parameters due to its complex microstructures. To further understand the UTS of GCI, it is necessary to evaluate the impact of various parameters. Herein, a UTS prediction method based on microstructure features and machine learning (ML) algorithms is proposed. The six regression algorithms, namely, Bayesian Ridge, Linear Regression, Elastic Net Regression, Support Vector Regression, Gradient Boosting Regressor (GBR), and Random Forest Regressor are used to develop the prediction models. The predicted results show that the GBR has the best prediction performance for the predicted UTS and the error bands within 5%. The feature importance indicates that matrix hardness has the greatest effect on the UTS in the ML models. [ABSTRACT FROM AUTHOR]

In this study, the Response Surface Methodology (RSM) was utilized to optimize process variables for butt friction stir welding (FSW) of aluminum alloys 6061 (AA 6061) and 7075 (AA 7075), known for their industrial relevance. The focus was placed on maximizing the ultimate tensile strength (UTS) and welding zone hardness (WZH) of the joints. The tool rotational speed (W) and welding speed (V) were investigated as key process parameters influencing the mechanical characteristics of the welds due to the plastic deformation of the base metals during FSW. Experiments were devised using a central composite design (CCD) and executed, with the outcomes evaluated via Minitab17 software. Subsequent analysis of variance (ANOVA) confirmed the adequacy of the developed models. It was discerned that both UTS and WZH are significantly affected by the linear and quadratic terms of W and V, as well as their interaction. Fracture characteristics of the welded joints were examined through scanning electron microscopy (SEM), correlating microstructural features with mechanical properties. Optimum welding conditions were identified at a tool rotational speed of 290 rpm and a welding speed of 13 mm/min, achieving an average UTS of 193.985 MPa and a WZH of 119.274 HV. The congruence between experimental results and predictive models underscores the reliability of the optimization process. [ABSTRACT FROM AUTHOR]

In this study, we facilitated the electrode welding of a micro-battery utilizing a laser through the application of a convolutional neural network (CNN) for the classification of micro-battery welding quality, utilizing a dataset comprised of battery-welded images. While prior studies focused on enhancing CNN performance through virtual image generation and conversion, our approach distinguishes itself by optimizing the CNN's performance through the adjustment of hyperparameters within the feature extraction section and the application of an image filter. To address insufficient image data, data augmentation and image shift techniques were implemented. The investigation delved into the influence of hyperparameters on CNN performance during the inspection of welding images, where the grayscale filter exhibited commendable performance in the context of battery welding images. Evaluation of the classification performance was conducted using a confusion matrix, revealing accurate identification of the two welding conditions. The experiments conducted in this study not only established the viability of the laser welding process but also demonstrated the potential of vision inspection using deep learning, presenting a practical solution for the micro-battery process. [ABSTRACT FROM AUTHOR]

This study presents an experimental investigation on the structural effects of an ignited fire occurring in a steel warehouse building with storage racks located at a part of an industrial plant. In order to judge whether the structure needs to be dismantled, repaired, or reused after the fire, an on-site postfire damage reconnaissance study was conducted, and postfire mechanical properties, such as tensile tests and Charpy V-notch impact tests, and chemical analysis of the structural steels used for the building, were determined depending on specimens removed from the fire-damaged structural steel members. The bearing system of the one story industrial steel building having a span of 25 m consisted of 12 fixed supported rigid gabled moment frames with rafters and 12 m high columns of H Section (HEA) 360. At the roof, the bracings of circular hollow section (CHS) 114.3×3.0 and the purlins of C180 were used, while at the level of 8.9 m, crane beams were designed as HEA 600. From the tensile and impact tests, stress-strain curves, yield strength, ultimate tensile strength, elongation at fracture, and impact energy of the steel specimens were achieved. After all the results obtained from the tests performed at room temperature were evaluated, it was concluded that the structural steel elements affected but showing no distortions after the fire could be reused conveniently. In addition, the proposed approach to estimate the temperature exposed by the structural steels during the fire could have the potential to contribute to the existing relevant literature. In this study, it is experimentally explained what can be done about whether a steel structure needs to be dismantled, repaired, or reused after a fire event. First performing on-site damage detection and then taking samples from the structural load bearing system members' chemical and mechanical tests should be carried out. Depending on the site investigation, it can be easily considered that the heavily deformed structural steel members become unusable and need to be renewed. From the tensile and impact tests of the structural steel elements affected but showing no distortions after the fire, their postfire mechanical properties are vital and should be ascertained. After all the test results were obtained, it can be concluded whether the structural steel members affected by fire can be reused, or need to be repaired or removed. In terms of ductility and elastic-perfectly plastic properties, it has been observed that after the fire the steel structural members showing no or even slight distortions can be reused conveniently. Thus, due to high cost of reconstruction of a steel building, a meaningful economy as well as acquisition in time can be achieved with this approach. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The present study aims to refine the solidification structure of 2319 Al-alloy Wire Arc Additive Manufacturing (WAAM) deposits by adding SiC powder to the interlayer during deposition. The fabricated deposits are subjected to aging treatment. The influence of SiC particle addition and aging treatment on evolution of microstructure and the corresponding hardness and tensile properties was investigated. To enable systematic understanding of the process, thermal simulation using ANSYS has been done for a single layer deposition and compared with the experimental data. The peak temperature for the deposits made with and without SiC particle addition is around 927.53 °C and 915.43 °C respectively. Three distinct structural zones were clearly seen in as-deposited specimens made without SiC particle addition. However, the deposits with SiC favored the formation of equiaxed grain throughout the specimen. The presence of α-Al and θ-Al2Cu phases in the as deposited specimen (without SiC) is confirmed through X-Ray Diffraction (XRD) and Electron Probe Micron Analyzer (EPMA), while the specimen deposited with addition of SiC particles demonstrates the presence of α-Al, θ-Al2Cu, and SiC phases. Post-Deposition Heat Treatment (PDHT) aids in uniform formation of θ-Al2Cu precipitates in both specimens. Deposits fabricated with SiC (308 ± 5 MPa) recorded higher Ultimate Tensile Strength (UTS) in comparison to without SiC deposits (260 ± 5 MPa). On the other hand, after heat treatment, the as-deposited specimen (without SiC) achieved an UTS of 468 ± 5 MPa, while the deposit fabricated with SiC recorded an UTS of 484 ± 5 MPa. [ABSTRACT FROM AUTHOR]

Due to the time-consuming and costly nature of high-cycle fatigue experiments, correlations between fatigue strength and mechanical properties obtained through more simple and fast experiments can be interesting from an economic perspective. This review article aims to provide an overview of such relations established in the open literature from the 1980s to 2023 for conventionally manufactured steel grades. The majority of these models relate fatigue strength at a given fatigue life (often termed "fatigue limit" or "endurance limit") to ultimate tensile strength, yield strength (both static and cyclic), hardness, elongation, reduction in area, and Charpy impact energy. Relations taking flaws such as nonmetallic inclusions into account are also discussed. Additionally, models predicting S–N curves are provided. The various estimations are presented in tables, together with the materials and test conditions for which they were established. [ABSTRACT FROM AUTHOR]

Copper and its alloys are structural materials used in industries and engineering applications due to their excellent thermal and electrical conductivity and chemical stability. Integrating graphene, known for its exceptional electrical conductivity, into the copper matrix is a promising strategy to enhance mechanical properties without sacrificing electrical conductivity. The Accumulative Roll Bonding (ARB) process can effectively and homogeneously introduce graphene into the metal matrix and is adaptable to an industrial scale. This study investigates the impact of varying graphene concentrations and two heat treatment protocols (without a controlled atmosphere) on the mechanical and electrical properties of ARBed copper/graphene composites. Optical microscopy revealed minimal voids and graphene clumps, and the energy dispersive spectroscopy analysis revealed the absence of copper oxide in some samples. The conductivity test showed little influence of the graphene content and stress relief heat treatment temperature on electrical conductivity (~86% of the International Annealed Copper Standard) within a limited number of ARB cycles. The tensile tests did not reveal a significant influence of the graphene content and stress relief heat treatment temperature on the ultimate tensile strength (220–420 MPa) and elongation (~2%). [ABSTRACT FROM AUTHOR]

Copyright of New Building Materials / Xinxing Jianzhu Cailiao is the property of New Building Materials Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study investigates the utilization of cyclic heat treatment (CHT), also referred to as thermal cycling, to design microstructures in steel to achieve specific properties. Through a comprehensive review of existing literature, it analyzes the influence of CHT on microstructure, strengthening mechanisms, and structure-property relationships, drawing parallels with conventional heat treatment methods. Mechanical properties are examined to establish meaningful correlations with structural modifications. The study delves into the impact of CHT parameters on microstructural changes and suggests to optimize these parameters to attain an ideal microstructure. While underscoring the potential advantages of CHT in enhancing steel's mechanical properties, it also conscientiously acknowledges its limitations, concluding with valuable recommendations for future research and practical implementation. [ABSTRACT FROM AUTHOR]

This research investigated changes in the properties of Sn–4.0Zn–0.7Cu (SZC407) solder alloy after doping with 0.5 wt % Ni. Specimens of SZC407 and SZC407–0.5Ni solder alloys were characterized in terms of chemical composition, microstructure, mechanical properties, and melting point. The results showed that the addition 0.5 wt % Ni had no significant effect on the ultimate tensile strength and elongation of SZC407 solder alloy but the formation of phases of the intermetallic compound (IMC) CuZnNi in the solder matrix increased the microhardness of the alloy. These IMC phases improved the strength of the solder matrix by the dispersion strengthening mechanism. The fracture surface of both solder alloys was typical of the ductile fracture mode. The microstructure of the solder alloy was improved by the distribution in the solder matrix of new CuZnNi IMC phases. However, the addition of 0.5 wt % Ni slightly increased the solidus and liquidus temperatures, pasty range and peak temperature of the SZC407 solder alloy. [ABSTRACT FROM AUTHOR]

The increased recycling in aluminum production has raised the impurity content in the industry, thus increasing its effect on mechanical characteristics and making it difficult for recycled products to meet the properties' goals as their effect is not yet sufficiently known. Therefore, the two main impurities (Fe and Si) in standard aluminum rolling mill products of alloy 5754 were investigated to determine their effects on the ultimate tensile strength (UTS). After analyzing the composition, mechanical properties, and microstructure, the relationship of both impurities with the UTS in fully annealed products was estimated by statistical analysis, obtaining a strong influence of Si and Fe. [ABSTRACT FROM AUTHOR]

Structural components are generally composed of material discontinuities, including open holes, which are considered stress concentrators in engineering components. In view of this, assessing the influence of open holes on the tensile properties is crucial to determine the sensitivity and tensile strength of a particular material. Nevertheless, investigation of the impact of open holes on the tensile properties of SS400 steel sheets is very limited and yet to be explored. Therefore, this study was performed to optimize the effects of open holes on the tensile properties of SS400 sheet specimens based on a Full Factorial Design (FFD) experiment. Four input parameters that represent various hole configurations, which include the hole diameter, location of the hole, number of holes, and hole shape, were considered in this study to develop the experimental-based prediction models to optimize the output performance, namely yield strength, ultimate tensile strength, and ultimate elongation, commonly denoted as YS, UTS, and UE respectively. A total of 10 additional experimental trials were then utilized to verify the constructed models. In addition, the weight fractions for YS, UTS, and UE were identified using the Criteria Importance Through Inter-Criteria Correlation (CRITIC) method. Subsequently, the Desirability Function Analysis (DFA) is utilized to pinpoint the optimal parameter conditions for maximizing the tensile properties. Based on the results, all four parameters showed significant effects on the response variables, except the number of holes for UTS and hole location for UE. The diameter also recorded the highest contribution toward UTS and UE, followed by the hole shape. Regarding YS, hole diameter takes precedence, with the number of holes as the second most influential factor. Furthermore, the average absolute percent deviation for the prediction responses of 10 experimental cases were 1.06 %, 0.90 %, and 0.85 % for YS, UTS, and UE, respectively, confirming the validity of the constructed models. Meanwhile, the CRITIC method estimated the weight fractions for YS, UTS and UE from the experimental data, which were 0.3825, 0.2559, and 0.3616, respectively. The DFA-derived composite desirability, rated at 0.9820, suggests optimal conditions: a 1 mm hole diameter, centered hole location, three holes, and a hexagonal shape. The minimal deviations between predicted and experimental values affirm the robustness of the models. Overall, this investigation yields important insights for optimizing open holes and elevating the tensile performance of SS400 sheet specimens.

AbstractThis study investigates the relationship between four welding input parameters (voltage, current, heat input, and welding speed) and the ultimate tensile strength (UTS) and yield strength (YS) of a welded joint. The work joined two super-duplex stainless-steel pipes of outside diameter 0.630 inches (16.002 mm) and a thickness of 0.065 (1.651 mm), using Gas Tungsten Arc Welding. Factorial design was used to ascertain the main and interaction effects of the welding input parameters on the UTS and YS of the welded joint. Results revealed a significant interaction between voltage, current, welding speed and heat input for UTS, and a significant interaction between the welding speed and heat input for YS. Results further revealed that as voltage increases from 9.3 V to 11.6 V, the UTS decreases by 2.69 MPa, while YS increases significantly by 24.25 MPa. When the current increases from 30 A to 38 A, the UTS increases by 10.81 MPa, while the YS increases by 4.25 MPa. In the case of the welding speed, an increase from 0.46 to 0.71 mm/s results in a decrease of the UTS by 7.94 MPa and a significant increase of the YS by 33.25 MPa. When the heat input increases from 0.54 to 0.70 kJ/mm, the UTS decreases by 15.06 MPa, whereas the YS decreases significantly by 35.25 MPa. Also, the optimum voltage, current, welding speed and heat input for UTS are 11.60 V, 30.0 A, 0.71 mm/s, and 0.70 kJ/mm, respectively, and those of YS are 9.30 V, 30.0 A, 0.46 mm/s, and 0.70 kJ/mm, respectively.

The Zirconium 702 alloy effectively used in nuclear industry at various critical conditions like high temperature and high pressure. This survey is an assessment of insights into the mechanical properties of the metal when exposed to different temperatures along the rolling direction.The main objective of this work is to characterize the tensile properties, and fracture study of broken tensile test samples at various temperatures.The tensile samples tested in our current work are 100°C,150°C, and 200°C temperatures in different directions (0°, 45°, 90°) along with the rolling direction of the sheet. It is evident from the experimental results that temperatures significantly affect material properties. Temperature increases cause % elongation to increase, and strength decreases. ANOVA analysis revealed that temperature significantly influenced ultimate tensile strength (UTS), and yield strength (YS), as well as % elongation.The temperature contribution for UTS, YS, and % elongation is 41.90%, 31.60%, and 77.80% respectively. SEM fractured images showing the ductile type of behavior for all the temperatures.

Selective laser sintering (SLS) is one of the additive manufacturing technologies dedicated to the production of high-quality parts with complex geometries. Here, polyamide 12 (PA12) is a commonly used material, for manufacturing parts with sufficient mechanical and thermal properties. In SLS, many manufacturing parameters have an effect on the mechanical properties of final parts. Even the decision regarding the orientation of a part in a powder bed may have a significant effect on the mechanical properties. In this research, the influence of horizontal (H) and vertical (V) printing orientations on the ultimate tensile strength (UTS) of fabricated PA12 specimens are examined. Our research findings show that H specimens exhibit larger deformations and smaller UTS value scatter in comparison with V specimens. Also, worth pointing out is the fact that V-oriented specimens have a higher elastic modulus. One can assume that the sintering process is more effective in V specimens, due to a more uniform laser beam trajectory than in the H specimens' case. [ABSTRACT FROM AUTHOR]

The present study aims to investigate the effect of the mechanical and metallurgical joint strength behavior of Cr-Ni-Mo steel (AISI 316) using direct drive friction welding. Experimental procedures in the study included macrostructure, microhardness, tensile test specimens with effective diameters of 4 mm, 6 mm, and 8 mm, microstructure of the fracture position, and tensile fracture morphology. The results concluded that the average microhardness values for 4 mm, 6 mm, and 8 mm diameter around the weld interface center are 298 Hv0.1, 300 Hv0.1, and 295 Hv0.1, respectively. The ultimate tensile strength ratios were of 95%, 98%, and 97% for 4 mm, 6 mm, and 8 mm, respectively, while, the ductility increased with the diameters of 41%, 50%, and 57% for 4 mm, 6 mm, and 8 mm, respectively, compared to AISI 316. The fracture position for all welded joints was in the adjacent region to the interface. The fracture surfaces had a fingerprint form and ductile mode at cleavage features. The center of the fracture revealed different forms of dimples and microcavities collected at that center. [ABSTRACT FROM AUTHOR]

Improved mechanical and thermal properties are important characteristics for enhancing the performance of cast iron components that operate at elevated temperatures. Thermal conductivity defines the temperature distribution within the casting and influences the magnitude of the thermally induced tensile stresses. The microstructural features that increase the thermal conductivity have a negative impact on tensile strength. The results reported in this work show that there is a unique inverse relationship between thermal conductivity and tensile strength, valid for the whole range of cast iron alloys regardless of graphite form, solidification rates, carbon content and matrix constituents. The finding indicates the challenges for the simultaneous improvement of these properties, and it can be utilized as a guideline during the design of cast iron components for high temperature applications. [ABSTRACT FROM AUTHOR]

In this study, the friction stir extrusion process as a new method was used to produce AA 1050 aluminum composite wires reinforced with silicon carbide (SiC) powder. The effect of process parameters on temperature (T), porosity (P) and ultimate tensile strength (UTS) was evaluated using the response surface method based on the Box-Behnken design. The input parameters included rotational speed (RS), extrusion force (EF) and reinforcement weight percentage (RF). Moreover, the microstructural evaluation of composite samples was conducted using optical microscope and scanning electron microscope. Finally, analysis of variance and regression analysis were used to obtain an appropriate model and confirm the accuracy of the results. The results showed that the temperature was increased by increasing the rotational speed to 1000 r/min and decreasing the extrusion force to 5.5 kN. Moreover, the lowest porosity value (averaged = 0.5%), and the highest tensile strength value (averaged = 153 MPa) were obtained at RS = 750 r/min, EF = 10.5 kN and RF = 3%. This can be attributed to the uniform distribution of reinforcing particles and strong interfacial bonding between SiC particles and the aluminum matrix. Also, the most effective parameter in the process was rotational speed which exhibited the greatest influence on P (53%) and UTS (41%) of composite samples. However, reinforcement weight percentage had the least effect on P (14%) and UTS (28%). [ABSTRACT FROM AUTHOR]

The incorporation and doping of elements represent a widely used approach to enhance the solidity, integrity, and characteristics of pb-free solder joints. The present study summarizes the incorporation of indium and its impact on the mechanical aspects of the SAC105 pb-free solder alloy. To refine the mechanical impact of the solder alloy, the evaluation of samples were categorized into three groups: as-cast, low-thermal aged (at 125 °C), and high-thermal aged (at 180 °C). The tensile deformation data were obtained via the universal tensile machine (UTM). Investigational findings demonstrated the enhancement in mechanical characteristics, including ultimate tensile and yield strength of the solder alloy. The addition of 1 wt.% of indium to SAC105 led to a notable increase in ultimate tensile strength, rising from 29.6 MPa to 35.31 MPa, which corresponds to an approximate 19.30% increase over the initial value. [ABSTRACT FROM AUTHOR]

Copyright of Materials & Technologies / Materiali in Tehnologije is the property of Institute of Metals & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Metallic nanowires are now extensively used in several nanoscale devices and applications. To further enhance their efficient usage, the estimation and prediction of thermal and mechanical properties of these nanowires is very important. Performing experimental studies on the objects of such a small dimension is quite challenging. Molecular dynamics simulation technique can easily simulate and perform virtual experimentation on the objects of nanoscale dimensions. In the present work, silver nanowires of known dimension simulated and a uniaxial stress has been implemented using the Molecular dynamics approach. The stress-strain data generated by MD simulation, has been utilized to train, test and validate different machine learning models. These machine-learning models offer a reasonably good amount of predictability of the tensile characteristics of the silver nanowire at any temperature. [ABSTRACT FROM AUTHOR]

Due to the time-consuming and costly nature of high-cycle fatigue experiments, correlations between fatigue strength and mechanical properties obtained through more simple and fast experiments can be interesting from an economic perspective. This review article aims to provide an overview of such relations established in the open literature from the 1980s to 2023 for conventionally manufactured steel grades. The majority of these models relate fatigue strength at a given fatigue life (often termed “fatigue limit” or “endurance limit”) to ultimate tensile strength, yield strength (both static and cyclic), hardness, elongation, reduction in area, and Charpy impact energy. Relations taking flaws such as nonmetallic inclusions into account are also discussed. Additionally, models predicting S–N curves are provided. The various estimations are presented in tables, together with the materials and test conditions for which they were established.

Additive friction stir deposition (AFSD) is attractive for its ability to create freeform and fully dense structures without melting and solidification. Hence, additive friction stir deposition is an alternative to fusion-based additive manufacturing technology. In this study, the influence of the AFSD parameter (i.e., rotational speed and feed rate) on the mechanical properties and microstructure of 6061 aluminum alloy is investigated. The as-deposited 6061 aluminum alloy exhibits a relatively homogeneous microstructure with extensive equiaxed grains. Compared to the feedstock material, the ultimate tensile strength of the as-deposited 6061 aluminum alloy decreased to 65% from 320 to 210 MPa. The results of electron backscatter diffraction indicate that continuous dynamic recrystallization occurs during the AFSD process. Furthermore, it is evidence that the grain size and ultimate tensile strength are positively correlated with feed rate and rotational speed, whereas the elongation at break decreases with the increase in feed rate and rotational speed. [ABSTRACT FROM AUTHOR]

To study the effects of Fe content and cold drawing strain on the microstructure and properties, Cu-Fe alloys were prepared via powder metallurgy and hot extrusion. Scanning electron microscopy was applied to observe the Fe phase, and the ultimate tensile strength was investigated using a universal material testing machine. Alloying with an Fe content below 10 wt.% formed a spherically dispersed Fe phase via the conventional nucleation and growth mechanism, whereas a higher Fe content formed a water-droplet-like Fe phase via the spinodal decomposition mechanism in the as-extruded Cu-Fe alloy. Further cold drawing induced the fiber structure of the Fe phase (fiber strengthening), which could not be destroyed by subsequent annealing. As the Fe content increased, the strength increased but the electrical conductivity decreased; as the cold drawing strain increased, both the strength and the electrical conductivity roughly increased, but the elongation roughly decreased. After thermal–mechanical processing, the electrical conductivity and strength of the Cu-40Fe alloy could reach 51% IACS and 1.14 GPa, respectively. This study can provide insight into the design of high-performance Cu-Fe alloys by tailoring the size and morphology of the Fe phase. [ABSTRACT FROM AUTHOR]

The chemical composition of M0 grade copper strips obtained at the Dong Nai machine-building plant (Vietnam) has been studied. The results of tensile testing of the samples of such strips are presented, which made it possible to determine the deformation resistance (yield strength), ultimate tensile strength, and percent elongation before and after rolling with a percent reduction of the cross-section area of ε = 10–30%. Based on the obtained data, curves were constructed that allowed us to establish quantitative trends in the variations of metal deformation resistance (yield strength) (σs), ultimate tensile strength (σt), and percent elongation (δ) depending on the degree of deformation of copper M0. It is shown that the ultimate tensile strength (σt) and yield strength σ0.2 (σs) increase with different intensity as the percent reduction increases. The σt parameter demonstrates a slow linear monotonic increase from 221 to 315 MPa as the percent reduction changes from 0 to 30%; while σ0.2 (σs) increases intensively according to the parabolic law from 41 to 308 MPa. The ductility index decreases from 63 to 16% within this deformation range. Regression equations have been obtained for calculating the basic mechanical properties of copper M0 during the process of cold rolling at various reductions. The adequacy of the obtained equations, confirmed by high correlation coefficient values (R2 > 0.9), makes it possible to recommend them for calculating the power characteristics of the rolling process, as well as for use in the automated design (CAD) systems to determine the rational copper strips (M0) deformation conditions at the industrial sheet rolling mills. [ABSTRACT FROM AUTHOR]

The present research focuses on the effect of process parameters on the tensile strength of near eutectic aluminum-silicon alloy in a Universal Centrifugal Casting Machine (UCCM). A Universal Centrifugal Casting Machine setup is developed to enhance the properties of a centrifugally cast component at any angle between 0° and 90° degrees. In this paper, untouched area of the centrifugal casting process (intermediate stages between horizontal centrifugal casting and vertical centrifugal casting process) has been studied. The ultimate tensile strength obtained with intermediate stages has been compared with the tensile strength obtained with traditional horizontal and vertical centrifugal casting processes. One factor at a time approach was used to understand the effect of process parameters like mold orientation, mold rotation, and mold preheat temperature on tensile strength. As per ASTM standards, tensile specimens were prepared from the casted cylinders to know the tensile strength of the casted parts. Tensile strength has been measured for each experiment, and the effects of each process parameter have been analyzed. Optimum values of different process parameters have been identified based on experimental analysis. [ABSTRACT FROM AUTHOR]

In this work, dissimilar welded joints from AISI 1330 and AISI 4340 low-alloy carbon steels produced using rotary friction welding (RFW) are investigated. These steels are intended for the manufacture of exploration drill pipes: AISI 4340 — the tool joint and AISI 1330 — the body of the pipe. Statistical analysis based on response surface methodology (RSM), microstructural examination using scanning electron microscopy with backscattered electron diffraction (EBSD), and mechanical tests were performed to investigate the friction weld joints. Equations are derived for predicting the notch tensile strength, ultimate tensile strength, and relative elongation from RFW process parameters (heating pressure, forging pressure, rotation speed during heating, burn-off length). The results showed that the rotation speed during heating and the heating pressure to the greatest extent affect the quality of the welded joint. Parameters have been established that ensure obtaining the mechanical properties of the welded joint at the level of the base metal AISI 1330: heating pressure 60–80 MPa, forging pressure 120–140 MPa, rotation speed during heating 400 rpm, and burn-off length 4 mm. It is shown that the strength of the joint depends on the development of processes of mutual dynamic recrystallization at the steel interface and strain hardening in the thermomechanical affected zone. [ABSTRACT FROM AUTHOR]

The use of materials for computer-aided design/computer-aided manufacturing (CAD/CAM) has been rapidly increasing in daily practice. However, one of the main issues regarding modern CAD/CAM materials is their aging in the oral environment, which may lead to significant changes in their overall properties. The aim of this study was to compare the flexural strength, water sorption, cross-link density (softening ratio%), surface roughness, and SEM analysis of three modern CAD/CAM "multicolor" composites. Grandio (Grandio disc multicolor—VOCO GmbH, Cuxhaven, Germany), Shofu (Shofu Block HC—Shofu Inc., Kyoto, Japan), and Vita (Vita Enamic multiColor—Vita Zahnfabrik, Bad Sackingen, Germany) were tested in this study. They were prepared in stick-shaped specimens and submitted to different tests after several aging protocols, such as thermocycling and mechanical cycle loading challenge. Further disc-shaped specimens were also created and tested for water sorption, cross-link density, surface roughness, and SEM ultramorphology, before and after storage in an ethanol-based solution. For flexural strength and ultimate tensile strength, Grandio showed the greatest values both at baseline and after aging (p < 0.05). Grandio and Vita Enamic presented the highest modulus of elasticity and the lowest water sorption (p < 0.05). A significant reduction (p < 0.05) in microhardness after ethanol storage (softening ratio%) was observed especially in Shofu. Grandio had the lowest roughness parameters compared to the other tested CAD/CAM materials, while ethanol storage significantly increased the Ra and RSm values in Shofu (p < 0.05). Despite the comparable modulus of elasticity of Vita and Grandio, this latter showed greater flexural strength and ultimate tensile strength both at baseline and after aging. Hence, Grandio and Vita Enamic may be employed for the anterior teeth and for those restorations requiring load-bearing capacity. Conversely, aging seems to affect several properties of Shofu, so its use for permanent restorations should be well-pondered based on the clinical situation. [ABSTRACT FROM AUTHOR]