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To achieve the desired microstructural properties, the ongoing development and innovation in new structural steels require novel thermal processing. This study aims to improve the mechanical properties of a commercial spring carbon–silicon steel by tailoring its microstructure through a process involving quenching and partitioning (Q&P) followed by bainitic transformation. A two‐stage Q&P process is proposed to generate a nanoscale dispersion of stable retained austenite and carbides within the tempered martensite and bainite microstructure. The resulting tensile properties demonstrate a yield strength of 1280 MPa, an ultimate tensile strength of 1875 MPa, and a total elongation of 8.03%. These values surpass those of conventional spring 9254 steel, highlighting the effectiveness of the thermal treatment design. Microstructure analysis reveals the presence of tempered martensite, bainite sheaves, nanoscale carbides, and aggregates of retained austenite. Moreover, the resulting body‐centered cubic matrix exhibits minimal lattice tetragonality of ≈1.0051, coupled with stable retained austenite featuring a carbon concentration of ≈3.42 ± 0.5 wt%, resulting in outstanding strength–ductility properties. These findings indicate that the proposed two‐stage Q&P process, followed by bainitic transformation, significantly enhances the mechanical properties of carbon–silicon steels, making it a promising candidate for high‐performance spring applications. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This research aims to determine the influence of water-soaking on polyester-based coated woven fabrics for ultimate tensile strength and elongation at break under uniaxial tensile tests. The paper begins with a short survey of literature concerning the investigation of the determination of coated woven fabric properties. The authors carried out the uniaxial tensile tests with an application of a flat grip to establish the values of the ultimate tensile strength of groups of specimens treated with different moisture conditions. SEM fractography is performed to determine the cross-section structures of coated woven fabrics. The change in the mechanical properties caused by the influence of water immersion has not been noticed in the performed investigations. [ABSTRACT FROM AUTHOR]

In the present study, aluminium hybrid surface composites were prepared by incorporating boron carbide (B4C) and Aluminium oxide (Al2O3) ceramic particles via the Friction Stir Processing (FSP) route. Tool rotational speed, Tool traverse speed, Axial force, and Reinforcement ratio were the chosen process parameters. Response Surface Method (RSM) based Central Composite Design (CCD) was used to conduct the experimental trials. A second-order regression equation was developed for the responses, ultimate tensile strength (UTS), and wear rate (WR). Statistical tests were performed to check the adequacy of the regression models. The effect of process parameters on the responses was studied. It was found that tool traverse speed was the most dominant process parameter, followed by tool rotational speed, axial force, and reinforcement ratio. The optimal process parameters for the responses were found using a genetic algorithm, where the regression equations from RSM were used as the objective function. [ABSTRACT FROM AUTHOR]

This paper aims to investigate the mechanical properties of specimens printed by 3D open-source printers. It discusses the effect of five factors (part orientation, layer height, extrusion width, nozzle diameter, and filament temperature) on the ultimate tensile strength and the impact toughness of the 3D-printed samples. A 25–1 resolution V fractional factorial experiment was run with the 16 samples printed on a Prusa I3 MK3S in PLA. Tensile strength and impact toughness were tested using Instron 3367 and Tinius Olsen 66 testers, respectively. In analyzing the data, a normal probability plot of the effects complimented with ANOVA (Analysis Of Variance) revealed that, for both responses, only part orientation was statistically significant at p = 0.05. Regression equations were used to predict the ultimate tensile strength and the impact toughness as a function of the part orientation. Both the toughness response and the tensile strength response are maximized with horizontal part orientation. Verification experiments have been implemented to validate the adopted regression equations' predictions under different circumstances, and the results of those experiments appear to confirm the model. [ABSTRACT FROM AUTHOR]

Improving the quality of parts printed using Fused Filament Fabrication (FFF) is of critical importance in a number of engineering applications. Providing additional thermal energy during printing by external means, or by an integrated heater has been investigated in the past to prolong the cooling curve, and therefore, ensure good adhesion with adjacent filaments. This work presents a modified heater block assembly to apply in-process thermal load during the upright printing of a Polylactic Acid (PLA) part. The design overcomes key shortcomings of past work and, in particular, addresses effective printing of thin, tall structures, where filament adhesion between layers is of particular importance. Cross-section imaging and tensile testing is combined with a comprehensive statistical design of experiments in order to fully understand the impact of process parameters on improved mechanical strength of printed parts. This work contributes towards improved properties and performance of realistic and practical FFF-printed parts. [ABSTRACT FROM AUTHOR]

The aim of the present study is to elucidate the influence of individual microstructural parameters, such as pearlite fraction, nodularity, and eutectic cell size, on the tensile strength (UTS) of cast irons. The UTS model was built by integrating the rule of mixtures for each microstructural component, and the UTS was described as a function of the aforementioned factors. The UTS and the required microstructure parameters for the model calculation were obtained experimentally. In the model, two coefficients were introduced to quantify the influence of the eutectic cell size and the interaction terms for the mixed two components. These coefficients were determined through fitting the experimental data, and the model's accuracy was validated using data not included in the fitting process. The results exhibited reasonable agreement, confirming the model's reliability. The model, thus, offers insights into the influence of each microstructural factor on UTS and serves as a guide for designing alloys to achieve the desired UTS through microstructure modifications. [ABSTRACT FROM AUTHOR]

In this work, based on the force-heat equivalence energy density principle and the theory of dislocation kinetics, a dislocation-based theoretical model of temperature-dependent ultimate tensile strength without fitting parameters is developed. The novelty of this model is that the theoretical characterization of the temperature-dependent dislocation annihilation energy barrier is implemented, and the new temperature-dependent expressions of the dislocation annihilation term and the dislocation storage term in the dislocation kinetics approach are derived. The model is well validated by comparing against available experimental results of pure face-centered cubic metals in a wide temperature range with the lowest temperature close to absolute temperature 0 K and the highest temperature close to melting point. Furthermore, the analysis results of the model show that increasing the dislocation storage coefficient and reducing the dislocation annihilation coefficient are effective measures to improve the ultimate tensile strength of metal materials, particularly at lower temperatures. The theoretical model provides a clear and profound physical basis for understanding the evolution of ultimate tensile strength at different temperatures. • The theoretical characterization of the temperature-dependent dislocation annihilation energy barrier is implemented. • The new temperature-dependent expressions of the dislocation annihilation term and the dislocation storage term are derived. • A physical dislocation-based model of temperature-dependent ultimate tensile strength is developed. • The effect of dislocation evolution coefficient on UTS at different temperatures is characterized. [ABSTRACT FROM AUTHOR]

A significant increase in 3D printing technology has been done primarily in the twenty-first century, where there are many research works going on in different fields, such as aerospace, automotive, and medical sectors to improve the 3D printing technology. This paper investigates the effect of printing with four different methods on the tensile strength of the Fused Deposition Modeling printed Polylactic Acid parts. Experimental and statistical analysis found that there is no effect in horizontal printing in both ways, but there is a significant difference in other printing methods. [ABSTRACT FROM AUTHOR]

Short fiber/polymer composites (SFPCs) are increasingly applied in the field of high‐temperature structures. Its reliability at high temperatures has always been the core issue concerned by researchers. Here, utilizing the Force–Heat Equivalence Energy Density Principle, we developed a physically based model of temperature‐dependent ultimate tensile strength (TDUTS) for SFPCs. This model quantitatively considers the evolution of residual thermal stress, interface, fiber, and matrix performance as temperature increases. Meanwhile, the influence of fiber agglomeration frequently observed in composites and fiber orientation and length distribution is taken into account in the proposed model. The model predictions over a wide temperature range are validated against the experimental data available from the literature, indicating its reasonability and accuracy. The comparison with Kelly–Tyson model and Li's model is also performed. Additionally, the quantitative effects of the fiber agglomeration and interfacial shear strength on the TDUTS are discussed in detail. The present research not only provides an accurate and feasible approach to estimate the TDUTS of SFPCs, but also offers some helpful insights for the fabrication and design of such composites. [ABSTRACT FROM AUTHOR]

Welding metal alloys with dissimilar melting points makes conventional welding processes not feasible to be used. Friction welding, on the other hand, has proven to be a promising technology. However, obtaining the welded joint's mechanical properties with characteristics similar to the base materials remains a challenge. In the development of this work, several of the machine learning (ML) regressors (e.g., Gaussian process, decision tree, random forest, support vector machines, gradient boosting, and multi-layer perceptron) were evaluated for the prediction of the ultimate tensile strength (UTS) in joints of AISI 1045 steel and 2017-T4 aluminum alloy produced by rotary friction welding with laser assistance. A mixed design of experiments was employed to assess the effect of the rotation speed, friction pressure, and laser power over the UTS. Furthermore, the response surface methodology (RSM) was employed to determine an empirical equation for predicting the UTS, and contours maps determine the main interactions. A total of 48 specimens were employed to train the regressors; the 5-fold cross-validation methodology was used to find the algorithm with greater precision. The gradient boosting regressor (GBR), support vector regressor (SVR), and Gaussian processes regressors present the highest precision with a less than 3% percentage error for the laser-assisted rotary friction welding process. The GBR and SVR capability exceed the RSM's accuracy with a coefficient of determination (R2) greater than 90.9 versus 83.2%, respectively. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of pre-heating a dual-polymerized adhesive and a dual-polymerized core build-up resin composite on their dentin micro-shear bond strength (µSBS), degree of conversion (DC%) and ultimate tensile strength (UTS). For µSBS, 45 human molars were divided into 9 groups (n = 5) according to two factors: (1) Adhesive temperature (25 °C/32 °C/40 °C) and 2- Resin composite temperature (25 °C/32 °C/40 °C). Dual-polymerized adhesive (Futurabond U/FBU) was applied over occlusal dentin at each temperature following the manufacturer's instructions. Four dual-polymerized composites (Rebilda DC/RDC, VOCO) micro-cylinders (1.2 mm diameter × 1 mm height) were built-up over each dentin disc, after being pre-heated at each temperature. After storage (48 h/37 °C), µSBS testing was run at a crosshead speed of 1 mm/min. DC% of FBU/RDC was evaluated at each temperature after 48 h using FTIR. Hourglass-shaped specimens were fabricated from both materials at each respective temperature and pulled apart to evaluate UTS after 48 h storage. Data were analyzed by ANOVA/Tukey's test/Pearson's correlation (p = 0.05). Neither adhesive/composite temperature nor their interaction had a significant effect on µSBS. No significant difference in µSBS between groups, except within 40 °C FBU. Predominant failure mode was a mixed type. No significant difference in DC% of FBU groups. RDC at 40 °C had significantly higher DC% than 25 °C. No significant difference in UTS of FBU and RDC groups. Application of both dual-polymerized adhesive and resin composite at 40 °C seemed to reduce µSBS. Raising the temperature to 40 °C improved DC% of resin composite, with no effect on adhesive. Pre-heating did not influence the UTS of both materials. [ABSTRACT FROM AUTHOR]

To improve the yield strength of powder metallurgy steel, this work investigated the effect of a Cu-rich networked phase. Mixtures of 0.7% graphite and Fe–3% Cu hybrid-alloyed steel powders, composed of pre-alloyed Fe–3 x % Cu particles with diffusion-bonded 3(1 − x) % Cu (0 ≤ x ≤ 1), were processed by high-density compaction and conventional sintering. The maximum values of 0.2% proof stress (YS) and ultimate tensile strength (UTS) were obtained at x = 0.68, where high-density compact with well-networked Cu-rich ferrite phase was developed without Cu growth. Moreover, nanosized ϵ-Cu precipitates were observed in the Cu-rich ferrite. These high YS and UTS were achieved not only by decreases in porosity but also by precipitation strengthening caused by the nanosized ϵ-Cu in the Cu-rich ferrite network. [ABSTRACT FROM AUTHOR]

Single-wall carbon nanotube (SWCNT) reinforced copper (Cu) matrix composites were fabricated by a simple procedure of rotating mixing and then spark plasma sintering (SPS). It was found that addition of SWCNTs as low as 0.05 wt% can increase the ultimate tensile strength (223.5 MPa) and elongation rate (48.0%) of composites by 20.8% and 57.9%, respectively, relative to those (185 MPa and 30.4%) of pure Cu material, while the composite electrical conductivity retained a high value of 94.3% International Annealed Copper Standard (IACS). Mechanism analyses revealed that there are nanometer Ni particles tightly attached to SWCNTs, which were formed in situ during SWCNT growth by arc discharge method. These nanometer Ni particles promoted the bonding between SWCNTs and Cu matrix, leading to a fracture-mode change from intergranular in pure Cu material to ductile in the composites. The related factors to influence the microstructure of composites were discussed as well. • Ni nanoparticles were formed in situ and tightly attached to SWCNT surfaces. • Addition of 0.05 wt% SWCNTs greatly increased both of strength and elongation of Cu. • A fracture-mode change occurs from intergranular in pure Cu to ductile in composites. • Load transfer is main mechanism responsible for enhancement in mechanical property. [ABSTRACT FROM AUTHOR]

In this study, considering the combined effects of the load carrying capacity of broken fibers and its evolution with temperature, a theoretical model for characterizing ultimate tensile strength of unidirectional ceramic-fiber reinforced ceramic composites (UCFRCCs) as a function of temperature is established. The model is verified by comparison with measurements available of temperature dependent ultimate tensile strength of UCFRCCs. Besides, on the basis of the established model, the quantitative influences of broken fibers and fiber Young's modulus on the ultimate tensile strength as a function of temperature are analyzed. The results show that the volume fraction of broken fibers and its strength contribution ratio at different temperatures are almost proportional to each other. Besides, the improvement of fiber Young's modulus at high temperatures is more conducive to enhancing the ultimate tensile strength of UCFRCCs. This study not only provides a powerful means to characterize the ultimate tensile strength, but also contributes to providing theoretical basis and guidance for the design and fabrication of UCFRCCs at various temperatures. [ABSTRACT FROM AUTHOR]

Friction stir welding process is increasingly used to connect metal structures for industrial applications as shipbuilding and offshore, aerospace, automotive, rolling stock for railways and robotics, Friction stir welding makes it much easier for us to fusion the aluminum alloys like AA6061-T651 and AA7075 -T651. it is essential to carefully study to contain many parameters such as the welding speed, the rotation speed and the type of pin used during the operation to optimize mechanical properties and in particular to obtain high rupture strength with the tensile test. [ABSTRACT FROM AUTHOR]

Optimizing two conflicting properties such as mechanical strength and toughness or dielectric constant and breakdown strength of a material has always been a challenge. Here we propose a machine learning approach to dramatically enhancing the combined ultimate tensile strength (UTS) and electric conductivity (EC) of alloys by identifying a set of key features through correlation screening, recursive elimination and exhaustive screening of existing datasets. We demonstrate that the key features responsible for solid solution strengthened conductive Copper alloys are absolute electronegativity, core electron distance, and atomic radius, based on which, we discovered a series of new alloying elements that can significantly improve the combined UTS and EC. The predictions are then validated by experimentally fabricating four new Cu-In alloys which could potentially replace the more expensive Cu-Ag alloys currently used in railway wiring. We show that the same set of key features can be generally applicable to designing a broad range of conductive alloys. Image, graphical abstract [ABSTRACT FROM AUTHOR]

In this study, the effect of welding parameters on the performance characteristic in the friction stir welding of Cu/Al plates were experimentally investigated. Experiments were designed according to Taguchi L9 orthogonal array. The evaluation of the experimental results was based on the signal/noise (S/N) ratio. Control factors that given optimum ultimate tensile strength and vickers hardness values determined by using Taguchi method. Three different tool rotational speeds (525, 1025 and 1525 rev/min), tool transverse speeds (50, 75 and 100 mm/min) and tool positions (0, 0.75 and 1.5 mm) as control factors have been selected. Optimal values of variables which were obtained using the S/N ratios were found at the same levels for ultimate tensile strength and hardness. According to the variance analysis results, the most significant variable affecting to ultimate tensile strength and hardness values was determined as tool position. Furthermore, for ultimate tensile strength and hardness values, first degree regression model was created by utilizing MINITAB 17 program. [ABSTRACT FROM AUTHOR]

Research conducted in the current paper examines the impact of the heat treatment at temperatures from 150 °C to 300 °C with time intervals between 1 and 6 hours on susceptibility to drawing process of Zn-Al15 wire rod manufactured within the industrial continuous casting and rolling line. The mechanical properties studies proved that the heat treatment caused the increase in the ultimate tensile strength values of the alloy whereas the drawing process caused a significant decrease, which suggests that this alloy after the specific heat treatment cannot be subjected to strain hardening. [ABSTRACT FROM AUTHOR]

In this paper, the acoustic impedance property has been employed to predict the ultimate tensile strength (UTS) and yield strength (YS) of pure metals and alloys. Novel algorithms were developed, depending on three experimentally measured parameters, and programmed in a MATLAB code. The measured parameters are longitudinal wave velocity of the metal, density, and crystal structure. 19-samples were considered in the study and divided into 3-groups according to their crystal structure; 7-FCC, 6-BCC, and 6-HCB. X-ray diffraction was used to examine the crystal structure of each sample of each group, while longitudinal wave velocity and metals' density were measured experimentally. A comparison between mechanical properties predicted by the model and the ASTM standards was done to investigate the validity of the model. Furthermore, predicted stress–strain curves were compared with corresponding curves in the pieces literature as an additional validation check. The results revealed the excellence of the model with 85–99% prediction accuracy. The study also proved that if metals are grouped according to their crystal structure, a relation between UTS, YS, and modulus of elasticity (E) properties and wave pressure transmission coefficient (Tr) could be formulated. [ABSTRACT FROM AUTHOR]

A numerical homogenization technique and morphological analysis based on the finite element method are used to compute mechanical properties of porous materials. This is achieved by considering two–dimensional matrix containing random distribution of identical non–overlapping circular or elliptical voids. Several microstructure configurations are obtained by varying the voids morphology and the porosity of the matrix. The notion of the representative volume element is used for numerical simulations in order to estimate the morphology effects of the voids on the effective ultimate tensile strength of the called Lotus – Type Porous Metals . A confrontation of the obtained numerical results of the representative microstructures for different morphologies of voids and different porosities to an analytical model and experimental data is performed. Finally, a formula improving the Boccaccini model is proposed to estimate effective tensile strength of porous metals taking into account the voids morphology. [ABSTRACT FROM AUTHOR]

The effect of primary austenite morphology on the ultimate tensile strength (UTS) of hypoeutectic compacted graphite Fe-C-Si alloys (CGI) is studied by isothermal coarsening experiments. Secondary dendrite arm spacing (SDAS) and the morphological characteristics related to the surface area of primary austenite, M γ and D ID Hyd, increase with the cube root of coarsening time. UTS decreases linearly with increasing coarseness of primary austenite. The eutectic and eutectoid microstructures are unaffected by the primary austenite morphology. These observations demonstrate the strong influence of primary austenite morphology on the mechanical properties of hypoeutectic CGI alloys. Unlabelled Image [ABSTRACT FROM AUTHOR]

Abstract 3D Printing is widely used in scientific researches and engineering applications, ranging from aerospace to biomedicine. However little is known about the mechanical properties of 3D printing materials. In order to promote the mechanical analysis and design of 3D printing structures, the ultimate tensile strength of FDM PLA materials with different printing angles were studied theoretically and experimentally. A theoretical model was firstly established to predict the ultimate tensile strength of FDM PLA materials based on transverse isotropic hypothesis, classical lamination theory and Hill-Tsai anisotropic yield criterion, and then verified by tensile experiments. Compared with previous models, this model provided two kinds of in-plane shear modulus calculation methods, so the calculation results were more reliable. The specimens, designed according to the current plastic-multipurpose test specimens standard ISO 527-2-2012, were printed in seven different angles ( 0 ∘ , 15 ∘ , 30 ∘ , 45 ∘ , 60 ∘ , 75 ∘ , 90 ∘ ) with three layer thicknesses (0.1 mm, 0.2 mm, 0.3 mm) for each angle. The relative residual sum of squares between theoretical data and experimental data were all close to zero, so the results that the theoretical model can accurately predict the ultimate tensile strength of FDM materials for all angles and thicknesses were confirmed. It was also found that the ultimate tensile strength decreased as the printing angle becomes smaller or the layer becomes thicker. This theoretical model and experimental method can also be applied to other 3D printing materials fabricated by FDM or SLA techniques. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to evaluate the degree of conversion, ultimate tensile strength, cell viability, and oxidative stress of two different ternary initiation systems, using two photoinitiation polymerization times. Methods: The groups investigated were camphorquinone (CQ); CQ and diphenyleneiodonium hexafluorophosphate (DPI); CQ and ethyl 4-dimethylamine benzoate (EDAB); and CQ, EDAB, and DPI, with EDAB in high and low concentration. To assess the degree of conversion (DC) and the ultimate tensile strength (UTS), a real-time Fourier transform infrared spectroscopy and a universal test machine Emic DL-500 were used, respectively. Cell viability and oxidative stress were evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide), superoxide dismutase (SOD), total sulfhydryl (SH) content, and thiobarbituric acid reactive species (TBARS) formation assays. Results: Slight lower cell viability was shown when DPI was associated with high concentrations of EDAB; this reduction seemed to be attenuated when lower concentrations of EDAB were used. When EDAB and DPI were associated, no oxidative damage was shown. The degree of conversion was increased in the ternary systems (CQ + EDAB lower concentration + DPI) group, which did not affect the UTS, cytotoxicity, and oxidative stress parameters. The polymerization time did not affect cell viability, total SH, and TBARS; however, a slight increase was shown in SOD levels. Clinical relevance: Our study emphasizes the relevance of incorporating the third element—iodonium salt—in a binary adhesive systems composed exclusively of CQ and EDAB. [ABSTRACT FROM AUTHOR]

The Small Punch (SP) test with constant deflection rate is a miniature technique that can provide estimates on the material tensile properties. Linear correlations are usually used for relating the maximum force and displacement at maximum force, recorded during the SP test, to the ultimate tensile strength. Fitting coefficients used in the correlations are calibrated on data from flat SP specimens. SP test requires only a small amount of testing material which represents a clear benefit when irradiated samples have to be tested. Therefore, there is a considerable interest in using SP for testing fuel cladding material properties. In this study we show that the same correlation equations, albeit with adjusted fitting coefficients, can be used to estimate the ultimate tensile strength from tube SP specimens made out of P91 ferritic/martensitic and 15-15Ti austenitic stainless steel. The calculated fitting coefficients lead to reasonable estimates of the ultimate tensile strength at temperatures of up to 650 °C although the coefficients themselves have been computed at room temperature. The coefficients are more suited for assessing ductile materials as the models used for computing the coefficients do not take into account damage (degradation of the material stiffness) or crack initiation and propagation, observed during the SP tests of brittle material. Finally, using the calculated ratios of maximum forces and displacements at maximum forces, one can map the two values of a given curved SP test to the equivalent flat SP values. [ABSTRACT FROM AUTHOR]

In this work, a mathematical relationship has been formulated between laser texturing process variables and the Ultimate Tensile Strength (UTS) of the AZ31B Mg alloy joints made by Cold Metal Transfer welding (CMTW) process. The nominal depth (D), diameter (Ø) and separation distance (SD) were the input parameters and three-factor and two-level central composite design (CCD) was applied to build up the experimental design matrix. By fixing the already optimized parameters of CMTW viz: current intensity 60A, Welding Speed 6 mm/sec, Gas flow rate 14 L/min and Nozzle to Plate Distance 6 mm and with the experimental matrix using laser texturing process variables, twenty joints were produced using CMTW process. The UTS was measured by standard ASTM procedure. The ANOVA was performed to find out the most significant main and interaction parameters and empirical relationship was determined. The laser texturing process (LST) variables were optimized by making response graphs and contour plots using Minitab software. The formulated mathematical relationship would be useful to forecast the UTS of CMT welded AZ31B joints for stipulated confidence limit. The contour plots will be helpful to acquire the optimal conditions of LST process variables. [ABSTRACT FROM AUTHOR]

Pulsed laser welding is a powerful technique especially suitable for joining thin sheet metals. In this study, based on experimental data, pulsed laser welding of thin AISI316L austenitic stainless steel sheet has been modeled and optimized. The experimental data required for modeling are gathered as per Central Composite Design matrix in Response Surface Methodology (RSM) with full replication of 31 runs. Ultimate Tensile Strength (UTS) is considered as the main quality measure in laser welding. Furthermore, the important process parameters including peak power, pulse duration, pulse frequency and welding speed are selected as input process parameters. The relation between input parameters and the output response is established via full quadratic response surface regression with confidence level of 95%. The adequacy of the regression model was verified using Analysis of Variance technique results. The main effects of each factor and the interactions effects with other factors were analyzed graphically in contour and surface plot. Next, to maximum joint UTS, the best combinations of parameters levels were specified using RSM. Moreover, the mathematical model is implanted into a Simulated Annealing (SA) optimization algorithm to determine the optimal values of process parameters. The results obtained by both SA and RSM optimization techniques are in good agreement. The optimal parameters settings for peak power of 1800 W, pulse duration of 4.5 ms, frequency of 4.2 Hz and welding speed of 0.5 mm/s would result in a welded joint with 96% of the base metal UTS. Computational results clearly demonstrate that the proposed modeling and optimization procedures perform quite well for pulsed laser welding process. [ABSTRACT FROM AUTHOR]

The main goal of this study is the modeling of ultimate tensile strength produced by friction stir welding of AA2024-T3 aluminum alloy using Taguchi and surface response methodologies. The considered process parameters are tool rotation speed, tool traverse speed, and wiper™ tool geometry (shoulder diameter). Analysis of variance, signal to noise ratio, and main effects plot used to check which process parameters were statistically significant and have better quality characteristics. Linear regression model was used to predict the ultimate tensile strength of the welded joints by incorporating process parameters. By using sensitivity analysis, the effectiveness of process parameters and the most significant parameter have been shown. From this research, the optimal experimental condition which gives the maximum ultimate tensile strength was obtained with a tool rotation speed of 750 rpm, a tool traverse speed of 100 mm/min, and a tool shoulder diameter of 12 mm which is 84% of joint efficiency of the base metal. The ultimate tensile strength increased to a maximum value and could be decreased with increasing tool rotation speed. Moreover, increasing the tool traverse speed or the tool shoulder diameter also make it decreased. Microscopic analysis showed that the increasing of the tool rotation speed or tool shoulder diameter results in an increase of average grain size in the nugget zone while it decreased slightly as tool traverse speed increases. [ABSTRACT FROM AUTHOR]

In this paper, a feed forward neural network with back propagation artificial neural network (BP ANN) was developed to predict ultimate tensile strength (UTS) and optimize microstructure. The alloys were produced by directional solidification and heat treatment. The UTS was measured for ANN output. Five characteristic factors used for ANN input were abstracted and measured. As the result of this study, the ANN model with high accuracy and good generalization ability to predict UTS within the range of 343.5–1063.3 MPa was established and mutual verified with sensitivity analysis. Based on the optimized ANN model, a new way to design microstructure of Nb-Si alloy to obtain required UTS was proposed. With silicide design maps made by ANN model, the microstructure of the sample of 343.5 MPa was optimized and the UTS reached the target UTS (600 MPa) successfully. [ABSTRACT FROM AUTHOR]

Nickel alloys have gathered wide acceptance in the fabrication of components, which require high temperature resistance and corrosion resistance, such as metal bellows used in expansion joints in aircraft, aerospace, and petroleum industry. In case of single pass welding of thinner sections of this alloy, pulsed current micro plasma arc welding (PCMPAW) was found beneficial due to its advantages over the conventional continuous current process. The quality of welded joint depends on the grain size, hardness, and ultimate tensile strength, which have to be properly controlled and optimized to ensure better economy and desirable mechanical characteristics of the weld. This paper highlights the development of empirical mathematical equations using multiple regression analysis, correlating various process parameters to grain size, hardness, and ultimate tensile strength in PCMPAW of Inconel 625 sheets. The experiments were conducted based on a five-factor, five-level central composite rotatable design matrix. A genetic algorithm (GA) was developed to optimize the process parameters for achieving the desired grain size, hardness, and ultimate tensile strength. [ABSTRACT FROM AUTHOR]

Ferrium® M54® exhibits an excellent UTS/K 1C balance allowing its application in aeronautical structures. This steel belongs to the Co-Ni UHS steels family with M 2 C nanometer-size carbide precipitation during tempering. These steels provide very high strength with a very good fracture toughness thanks to the M 2 C fine precipitation during tempering, but also because coarse particles are dissolved during austenitizing without grain coarsening. The goal of this article is to identify the different carbide populations in M54®. A small addition of Ti in M54® forms a Ti-rich MC carbide precipitation that is stable at high temperature. Consequently, during austenitization at 1060 °C, all other types of coarse carbides are dissolved in the matrix without grain coarsening. As a very small part of the initial carbon content is needed to form MC carbides, efficient and intensive nanometric M 2 C carbide precipitation takes place during tempering, leading to very high final strength. Due to this double precipitation of carbides in M54®, the steel achieves an outstanding UTS/K 1C balance. [ABSTRACT FROM AUTHOR]

The mechanical stability of an ideal elastic solid under infinitesimal and finitesimal changes in its state parameters is considered. The temperature and density dependences of the isothermic moduli of bulk compression K, simple shear, and tetragonal shear in a Lennard-Jones face-centered cubic (FCC) crystal have been determined by means of molecular dynamic experiments in the region of stable and metastable states. It has been shown that the crystalline phase remains stable under long-wave spatially nonuniform density fluctuations on the spinodal (K = 0) at pressures below the pressure of the endpoint of the melting line (p < pK < 0). Here, the critical nucleus formation work is also finitesimal. Hence, spinodal states in quasisteady- state processes at p < 0 not only are attainable, but the transition across the spinodal without destroying the homogeneity in the substance also proves to be feasible. In this case, the boundary of the ideal strength of a solid is set by the vanishing of the uniaxial compression modulus K˜ for a certain specified deformation direction. The spinodal also is not the boundary of the ideal strength of a solid at positive and small negative pressures. A solid loses its ability for a restorative response to finitesimal spatially nonuniform density disturbances before the spinodal (K˜ = 0) is attained. [ABSTRACT FROM AUTHOR]

In this study, effects of friction stir processing (FSP) parameters and hybrid ratio on the ultimate tensile strength (UTS) of aluminum (Al) matrix (5083) hybrid composites (AMHCs) were investigated in detail. In order to estimate the ultimate tensile strength of the prepared composites, a mathematical formulation was derived, and test results were compared with those of the model. The effects of factors influencing strength, such as tool rotational and traverse speeds, and volume fractions of, carbon nanotube (CNT), aluminum oxide (Al 2 O 3 ), graphite (Gr), silicon carbide (SiC) and zirconium oxide (ZrO 2 ) were also studied using the proposed formulation. Test results showed that the ultimate tensile strength of these composites significantly increased with increasing CNT, tool rotational and traverse speeds. In addition, the effects of complex reinforcements with different volume fractions on the 5083 AMHCs were examined. A maximum tensile strength for the hybrid composite was found at the inclusion ratio of 10% Gr + 5% ZrO 2 . This study may open up new possibilities to developing highly strength Al alloys for various industrial applications. [ABSTRACT FROM AUTHOR]

Instrumented Charpy test data have often been used to obtain estimates of various mechanical properties under elevated loading rates, such as dynamic yield properties. A widely used relationship between Charpy general yield force and dynamic yield strength was originally proposed by Server in 1978. This same relationship, however, cannot be used for estimating the dynamic (ultimate) tensile strength from the Charpy maximum force, since it relies on the ratio between shear and tensile stress, which at general yield is different than at maximum force. In the study described in this paper, we modified Server's relationship in order to obtain reliable, and possibly conservative, estimates of dynamic ultimate tensile strength from the maximum force measured in an instrumented Charpy test. Once more experimental data has been accumulated, the results of this investigation might have significant implications for the revision of fracture mechanics test standards which utilize dynamic ultimate tensile properties for the qualification/validation of fracture toughness tests conducted at elevated loading rates. [ABSTRACT FROM AUTHOR]

The relationships between fatigue strength and ultimate tensile strength as well as hardness have been studied in high-strength NZK alloys (Mg– y Nd– z Zn– x Zr) and other magnesium alloys. In the absence of casting defects, clear linear relationships have been found between the fatigue strength and the ultimate tensile strength and the hardness values in these magnesium alloys in both T4 (solutionized) and T6 (solutionized and aged) conditions. The fatigue strength models developed in this work alloys can be directly applied to other defect-free magnesium alloys. [ABSTRACT FROM AUTHOR]

A simulation model was developed for the monitoring, controlling and optimization of the Friction Stir Welding (FSW) process. This approach, using the FSW technique, allows identifying the correlation between the process parameters (input variable) and the mechanical properties (output responses) of the welded AA5754 H111 aluminum plates. The optimization of technological parameters is a basic requirement for increasing the seam quality, since it promotes a stable and defect-free process. Both the tool rotation and the travel speed, the position of the samples extracted from the weld bead and the thermal data, detected with thermographic techniques for on-line control of the joints, were varied to build the experimental plans. The quality of joints was evaluated through destructive and non-destructive tests (visual tests, macro graphic analysis, tensile tests, indentation Vickers hardness tests and t thermographic controls). The simulation model was based on the adoption of the Artificial Neural Networks (ANNs) characterized by back-propagation learning algorithm with different types of architecture, which were able to predict with good reliability the FSW process parameters for the welding of the AA5754 H111 aluminum plates in Butt-Joint configuration. [ABSTRACT FROM AUTHOR]

The ultimate tensile strength (UTS) and the yield strength (YS) are two key performances of copper wire, which vary synergistically under macroscopic conditions. However, they exhibit different dimensional sensitivity at small dimensions, which provides new ideas for designing materials. This study tested the UTS of copper wire with different dimensions after annealing. It was found that the UTS became weaker in a smaller dimension. Dislocations in the surface grains moved quickly to the sample surface of the microstructure. The density of dislocations in the grains decreased, which significantly reduced the strength at small dimensions. The YS arises with smaller dimensions because the growth of hard grains increased the difficulty in opening the slip system. The evolution of the Taylor factor (M) with dimensions explains the size effect in YS. The rapid increase in M value for small-size samples resulted in higher YS. [ABSTRACT FROM AUTHOR]

Quantitative evaluation of temperature effect on the mechanical properties of materials has always been the core issue concern. In this study, based on the Force-Heat Equivalence Energy Density Principle, a method to model the temperature-dependent ultimate tensile strength (UTS) for metallic materials was proposed. The critical plastic instability energy density related to the onset of plastic instability was put forward which is composed of the elastic-plastic strain energy and the corresponding heat energy. Subsequently, two temperature-dependent UTS models considering the effect of strain hardening behavior were theoretically derived. The models do not contain meaningless adjustable fitting parameters and each parameter has clear physical meanings. The intrinsic quantitative relationships between temperature, UTS, strain hardening exponent, strength coefficient, and specific heat capacity are revealed. Model predictions achieved good agreement with 31 groups of accessible metallic materials, including structural steels, high-strength steels, cold-formed steels, zirconium alloys, and aluminum alloys, which are commonly used in engineering. Especially, the models achieved a better agreement with the results of uniaxial tensile tests compared with the current indentation method. Furthermore, the quantitative influence of the strain hardening exponent and the strength coefficient on UTS at different temperatures was analyzed. This work will contribute to the evaluation of the properties of materials at elevated temperatures and the fire design of structures. • A method for modeling material temperature-dependent UTS was proposed. • Two temperature-dependent UTS models based on energy equivalence were developed. • A non-destructive method to predict temperature-dependent UTS of metallic materials. • Predictions are in good consistency with the experimental of 31 metallic materials. • The intrinsic quantitative relationship between temperature and UTS is revealed. [ABSTRACT FROM AUTHOR]

In the present work, the relation between ageing and retrogression temperatures on Al 6061 alloy hardness and ultimate tensile strength (UTS) was studied. It was found that higher UTS and hardness were obtained at higher ageing, retrogression temperatures, and lowest retrogression time. Controlling these parameters, alloy UTS has been improved 12% over T6 temper, showing a 40% reduction in time consumption during the thermal treatment. By means of a multiple linear regression method, a correlation has been established between UTS, hardness, and time/temperature for ageing and retrogression regimes, This correlation can be used to select adequate ageing temperature and retrogression time-temperature in order to obtain both specific UTS and hardness on aluminium 6061 alloy. [ABSTRACT FROM AUTHOR]

Friction stir welding (FSW) is a highly reliable joining process. However, there is still lack of optimized FSW parameters for different joint configurations. The present manuscript presents a set of optimization studies for different friction stir welding joint geometries of AA6082-T6 aluminium alloy: butt, lap and T joints. The optimization process was performed using Taguchi orthogonal arrays (OA) for designing experiments, analyses of the average effects (main effect plot) and variance (ANOVA). Welded joints were manufactured according to orthogonal arrays, selected using the Taguchi method, for each type of joint, and the ultimate tensile strength (UTS) was evaluated for statistical optimization. As a major asset for the current state of the art, this manuscript contribution is focused on the determination of the most relevant FSW parameters on UTS for a complete range of joints, as well as their interactions. In the particular case of lap and T joints, parameter optimization studies are lacking in the literature, and as such, this work aims at tackling the issue. The parameter combinations to achieve the best mechanical properties for each joint configuration were derived. [ABSTRACT FROM AUTHOR]

Strain rate, temperature, and microstructure play a significant role in the mechanical response of materials. Using non-equilibrium molecular dynamics simulations, we characterize the ductile tensile failure of a model body-centered cubic metal, tantalum, over six orders of magnitude in strain rate. Molecular dynamics calculations combined with reported experimental measurements show power-law kinetic relationships that vary as a function of dominant defect mechanism and grain size. The maximum sustained tensile stress, or spall strength, increases with increasing strain rate, before ultimately saturating at ultra-high strain rates, i.e. those approaching or exceeding the Debye frequency. The upper limit of tensile strength can be well estimated by the cohesive energy, or the energy required to separate atoms from one another. At strain rates below the Debye frequency, the spall strength of nanocrystalline Ta is less than single crystalline tantalum. This occurs in part due to the decreased flow stress of the grain boundaries; stress concentrations at grain boundaries that arise due to compatibility requirements; and the growing fraction of grain-boundary atoms as grain size is decreased into the nanocrystalline regime. In the present cases, voids nucleate at defect structures present in the microstructure. The exact makeup and distribution of defects is controlled by the initial microstructure and the plastic deformation during both compression and expansion, where grain boundaries and grain orientation play critical roles. [ABSTRACT FROM AUTHOR]

Abstract: Scintillating crystals are employed in high energy physics, in medical imaging, diagnostic and security. Two mechanical properties of lutetium–yttrium oxyorthosilicate cerium-doped Lu2(1−x)Y2x SiO5:Ce with x=0.1 (LYSO) crystals have been measured: the ultimate tensile stress (σ UTS) and the Young elastic modulus (E). Measurements are made by means of a 4-points loading device and the experimental results account for an elastic–brittle stress–strain relation, which depends heavily on the specimen preparation and the material defects. σ UTS along the [010] tensile direction ranges within 68.14 and 115.61MPa, which, in the lowest case, is more than twice with respect to those measured for PbWO4 (PWO), exhibiting a marked difference between the annealed and the not-annealed samples. The mean elastic modulus (E), along the same direction, is E=1.80×1011 (±2.15×1010)N/m2, with lower dispersion respect to UTS data. This type of analysis and study can be included into quality control procedures of crystals, based on samples taken out of production; such procedures can be established for industrial processing of crystals aimed to the high energy physics (calorimeters) and medical imaging (PET, etc.) applications. [Copyright &y& Elsevier]

Correlations for evaluation of Ultimate Tensile Strength (UTS) using Miniature Disk Bend Test (MDBT) or Small Punch Test (SPT) has been an open issue since the development of the techniques. The larger plastic strains, in tri-axial state of stress during SPT, make the translation to the equivalent uniaxial parameter less certain. Correlations based on P max of load–displacement curve are also in disagreement as the point corresponding to P max does not represent a necking situation as in case of UTS, in a uniaxial tensile test. In present work, an attempt has been made for locating necking zone, which appears prior to P max , through experiments and FEM analyses. Experimental results on disk specimens from 20MnMoNi55, CrMoV ferritic steel and SS304LN materials along with FEM analyses found that load corresponding to 0.48 mm displacement is to be very close to the necking zone, and gives best fit for a UTS correlation. [ABSTRACT FROM AUTHOR]

The aim of the current study was to evaluate the dimensional changes and ultimate tensile strength in three polyamide materials for denture bases fabrication through injection molding, subjected to artificial aging and different storage conditions. A total of 333 test specimens fabricated from Biosens (BS; Perflex, Netanya, Israel), Bre.flex 2nd edition (BF; Bredent, Senden, Germany) and ThermoSens (TS; Vertex Dental B.V., Soesterberg, The Netherlands)—n = 111 per material—were equally divided into three groups (n = 37) based on different treatments and storage conditions. Test samples allocated to the "Control group" were not artificially aged and stored in water for 24 h. Both "Treatment 1 group" and "Treatment 2 group" were subjected to thermocycling, the former dehydrated and the latter stored in water between cycle-sets. Linear changes and ultimate tensile strength were measured and analyzed for storage condition and material influence on the outcome variables. A Welch ANOVA test with Games–Howell post-hoc analysis was used to compare the influence of treatments across different materials. Significant differences were found for all three included materials with p values ranging from <0.05 to <0.001 for linear dimensional changes. The magnitude of alterations varied and was large for BS (Perflex, Israel) (ω2 = 0.62) and BF (Bredent, Germany) (ω2 = 0.47) and small but significant for TS (Vertex Dental B.V., The Netherlands) (ω2 = 0.05). However, results seem to fall into clinically acceptable range. Significant differences were also observed for the ultimate tensile strength test with the same range of p-values. All three materials showed different initial ultimate tensile strengths and varying reaction to artificial aging and storage with the lowest alterations observed for BF (Bredent, Germany) (ω2 = 0.05). Within the limitation of this study, it can be concluded that all three materials show different dimensional and mechanical properties when subjected to artificial aging and different storage. Although linear dimensions show significant changes, they seem to be clinically irrelevant, whereas the change in ultimate tensile strength after only 6-month equivalent clinical use was substantial for BS (Perflex, Israel) and TS (Vertex Dental B.V., The Netherlands). [ABSTRACT FROM AUTHOR]

Varying the carbon contents, chemical composition and solidification rate greatly influences the microstructural morphology in lamellar graphite iron resulting in large variations in material properties. Traditionally, ultimate tensile strength (UTS) is used as the main property for the characterisation of lamellar graphite iron alloys under static loads. The main models found in the literature for predicting UTS of pearlitic lamellar graphite iron are based on either regression analysis on experimental data or on modified Griffith or Hall-Petch equation. In pearlitic lamellar graphite iron the primary austenite transformed to pearlite reinforces the bulk material while the graphite flakes which are embedded in an iron matrix reduce the strength of the material. Nevertheless a dominant parameter which can be used to define the tensile strength is the characteristic distance between the pearlite grains defined as the maximum continuous defect size in the bulk material, which in this work is expressed by the newly introduced parameter the Diameter of Interdendritic Space. The model presented here covers the whole spectrum of carbon content from eutectic to hypoeutectic composition, solidified at different cooling rates typical for both thin and thick walled complex shaped castings. [ABSTRACT FROM AUTHOR]

A series of welds were made by friction stir welding (FSW) under different welding and rotation speeds. A 2D ultimate tensile strength (UTS) map was developed based on various experimental data to predict the UTS of friction stir welded AA2024 alloy joints. The accuracy of the UTS map was evaluated by comparing the estimated UTS with the corresponding experimental results from the FSW of the same material available in the open literature. Analytical models were developed to estimate the peak temperature and grain size in the nugget zone. The predicted optimal peak temperature and welding and rotation speeds for AA2024 were within the windows of 400-465 °C, 175-350 mm/min and 800-1,200 rpm, respectively, under which the joint tensile strength could be higher than 458 MPa (about 94.6 % of the base metal) and the estimated average grain sizes in the nugget zone were about 2-3.9 μm. [ABSTRACT FROM AUTHOR]

The paper presents some results of the research connected with the development of new approach based on the artificial neural network (ANN) of predicting the ultimate tensile strength of the API X70 steels after thermomechanical treatment. The independent variables in the model are chemical compositions (carbon equivalent), based upon the International Institute of Welding equation (CE IIW), the carbon equivalent, based upon the chemical portion of the Ito-Bessyo carbon equivalent equation (CE Pcm), the sum of the niobium, vanadium and titanium concentrations (VTiNb), the sum of the niobium and vanadium concentrations (NbV), the sum of the chromium, molybdenum, nickel and copper concentrations (CrMoNiCu), Charpy impact energy at −10 °C (CVN) and yield strength at 0.005 offset (YS). For purpose of constructing these models, 104 different data were gathered from the experimental results. The data used in the ANN model is arranged in a format of seven input parameters that cover the chemical compositions, yield stress and Charpy impact energy, and output parameter which is ultimate tensile strength. In this model, the training, validation and testing results in the ANN have shown strong potential for prediction of relations between chemical compositions and mechanical properties of API X70 steels. [ABSTRACT FROM AUTHOR]

Development of the Friction Stir Welding (FSW) - has provided an alternative improved way of producing aluminium joints, in a faster and reliable manner. This paper presents a systematic approach to develop a mathematical model for predicting the Ultimate Tensile Strength (UTS) of dissimilar aluminum alloy (AA6351 T6 - AA5083 H111) joints by incorporating the Friction Stir Welding (FSW) process parameter such as tool pin profile, tool rotational speed, welding speed, and axial force. The experiment was conducted based on four factors five level central composite rotatable deign with full replication technique. The Response Surface Method (RSM) was employed to develop the model. The developed model was validated using the statistical tool analysis of variance (ANOVA). Conformity tests were carried out to check the accuracy of the developed model. The effects of the FSW process parameters on ultimate tensile strength of friction welded dissimilar joints were discussed in detail. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of zinc methacrylate (ZM) on the inhibition of matrix metalloproteinase 2 (MMP-2) and the ultimate tensile strength (UTS) of an experimental polymer. Enzymes secreted from mouse gingival tissues were analyzed by gelatin zymography in buffers containing 5 mM CaCl (Tris-CaCl) in 50 mM Tris-HCl buffer with various concentrations of ZM (0.5, 1, 2, 4, 8, and 16 mM). The matrix metalloproteinases present in the conditioned media were characterized by immunoprecipitation. The polymer UTS evaluation was performed in eight groups with various concentrations of ZM (0, 0.5, 1, 2.5, 5, 10, 20, and 30 wt.%), in a mechanical testing machine. MMP-2 (62 kDa) was detected in the zymographic assays and inhibited by ZM in all tested concentrations. UTS data were submitted to one-way ANOVA and Tukey's test ( α = 0.05), and no significant differences were observed among groups, except in the polymer containing 30% ZM, presenting a significantly lower value when compared with the control group ( p < 0.05). The results suggest that ZM inhibits MMP-2 expression in all concentrations tested, while small concentrations did not affect the ultimate tensile strength of the polymer. Zinc methacrylate is a metalloproteinase inhibitor that can be copolymerized with other methacrylate monomers. Yet, the addition of ZM did not affect the resin bond strength. Thus, in vivo tests should be performed to evaluate the performance of this material. [ABSTRACT FROM AUTHOR]