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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]

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]

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]

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]

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]

Federal rule changes governing natural gas pipelines have made non-destructive techniques, such as instrumented indentation testing (IIT), an attractive alternative to destructive tests for verifying properties of steel pipeline segments that lack traceable records. Ongoing work from Pacific Gas and Electric Company's (PG&E) materials verification program indicates that IIT measurements may be enhanced by incorporating chemical composition data. This paper presents data from PG&E's large-scale IIT program that demonstrates the predictive capabilities of IIT and chemical composition data, with particular emphasis given to differences between ultimate tensile strength (UTS) and yield strength (YS). For this study, over 80 segments of line pipe were evaluated through tensile testing, IIT, and compositional testing by optical emission spectroscopy (OES) and laboratory combustion. IIT measurements of UTS were, generally, in better agreement with destructive tensile data than YS and exhibited about half as much variability as YS measurements on the same sample. The root-mean squared error for IIT measurements of UTS and YS, respectively, were 27 MPa (3.9 ksi) and 43 MPa (6.2 ksi). Next, a machine learning model was trained to estimate YS and UTS by combining IIT with chemical composition data. The agreement between the model's estimated UTS and tensile UTS values was only slightly better than the IIT-only measurements, with an RMSE of 21 MPa (3.1 ksi). However, the YS estimates showed much greater improvement with an improved RMSE of 27 MPa (3.9 ksi). The experimental, mechanical, and metallurgical factors that contributed to IIT's ability to consistently determine destructive UTS, and the differences in its interaction with composition as compared to YS, are discussed herein. [ABSTRACT FROM AUTHOR]

• Hot axial rolling was introduced in the quenching and partitioning (Q&P) process. • The tensile strength of Q&P steel is increased by 224 MPa without loss of plasticity. • The introduction of hot deformation promotes the diffusion of carbon atoms and formation of transition carbides. • The deformation direct quenching and partitioning (DQ&P) sample shows higher work-hardening rate than Q&P sample. Quenching and partitioning (Q&P) is a heat treatment process which can obtain high strength and good plasticity matching steels. In this study, hot axial rolling was introduced in the Q&P steel and the microstructure evolutions and mechanical behaviors were compared with traditional Q&P steel. The results show that the introduction of hot deformation can retain more austenite, produce higher dislocation density and promote the precipitation of transition carbides. The higher dislocation density and more closely spaced transition carbides increase the work-hardening rate, which can not only increase the ultimate tensile strength, but also ensure no loss of plasticity, that is, improve the comprehensive mechanical properties of the Q&P steel. [ABSTRACT FROM AUTHOR]

• Temperature-dependent ultimate tensile strength model was established for short fiber reinforced metal matrix composites. • Variation with temperature of the contribution of different mechanisms are firstly made. • Suggestions to improve the temperature-dependent ultimate tensile strength are provided. • The good agreement between theory and experimental results is obtained. In this paper, considering the combined influences of fiber strength and various strengthening mechanisms including load transmitting, dispersion strengthening, residual thermal stress and dislocation strengthening, and their evolution with temperature, a temperature dependent ultimate tensile strength theoretical model of short fiber reinforced metal matrix composites is established. The model is confirmed by comparing with the available experimental results of six different short fiber reinforced metal matrix composites. Then, based on the model we developed, the contribution of various strengthening mechanisms to the ultimate tensile strength of the composites with the evolution of temperature is analyzed. Besides, the quantitative influences of Young's modulus of fiber and matrix on the ultimate tensile strength evolution with temperature are discussed. Several opinions on the design of short fiber reinforced metal matrix composites are put forward, especially at high temperatures. [ABSTRACT FROM AUTHOR]

A temperature dependent ultimate tensile strength (TDUTS) model of polymer composites reinforced with fibers (FPCs) for a wide range of volume fractions was developed according to the Force-Heat Equivalence Energy Density Principle and combined with the Halpin-Tsai model. This model involved the quantitative evolution of thermo-physical performance of fiber, polymer with temperature, as well as the effects of fiber agglomeration, volume fraction, orientation and geometry. The predictive model was verified by comparing the predictions with the available experimental results of both short and unidirectional fiber/polymer composites for a wide range of temperature and volume fractions. To illustrate the effect of fiber agglomeration on the composite TDUTS, influencing factor analysis was also made. Compared with other classical models, this model predicts more accurate and only basic and easily accessible material parameters are required. This study demonstrates theoretical support to estimate the UTS of FPCs versus volume fractions at elevated temperatures, further provides opinion about the composite preparation and performance improvement. [Display omitted] [ABSTRACT FROM AUTHOR]

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]

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]

AbstractTo correlate µTBS of different resin cements with their film thickness (FT), Vickers hardness (HV), and ultimate tensile strength (UTS). Human molars (N = 30) were divided into six-groups according to 1: Resin cement: Bifix QM, (BF), GrandioSo Heavy Flow (GHF) and VisCalor Bulk (VB), and 2: Adhesive mode (Optibond Universal): Etch-and-rinse (E&R) or self-etching (SE). CAD/CAM blocks (7 × 7 × 4 mm3) were air-abraded using 50 μm Al2O3 and silane was applied (60 s), and air dried (10 s). For E&R, dentin was etched (15 s), rinsed (30 s), and blot-dried. For both modes, adhesive was applied (20 s), air-dried (5 s), and photo-polymerized (10 s). Sticks (1 × 1 mm2) were stored for 24-h or 6-months. Sticks were pulled in tension (1 mm/min). Debonded sticks were evaluated for failure mode analysis. For FT, nine-bonded slabs from each cement was prepared and evaluated. For UTS, eight-hourglass specimens from each cement were prepared and tested in tension. For HV, five-discs from each cement was prepared and evaluated using a HV tester. Data were analyzed using ANOVA/Pearson’s correlation tests (α = 0.05). No correlation between µTBS/HV was revealed (p > 0.05). A positive correlation between µTBS/FT and µTBS/UTS (p < 0.05) was observed. Three-way ANOVA revealed all experimental factors had a significant effect on µTBS (p < 0.05). The VB showed significantly lower µTBS (20.8 ± 9.3 MPa). The E&R mode showed higher µTBS (26.0 ± 10.9 MPa), and 24-h revealed a higher µTBS (27.4 ± 10.0 MPa). Mixed failure was the predominant type (42.51%). The VB showed the highest FT (122.2 ± 11.9 µm), with GHF revealed higher UTS and HV (112.5 ± 19.7 MPa and 91.6 ± 0.4 Kgf, respectively). Photo-polymerized flowable composite can substitute dual-polymerized cement for CAD/CAM composite bonding. [ABSTRACT FROM AUTHOR]

Twenty-two commercial steels with a bcc microstructure were tensile tested in reference atmosphere and in gaseous high-pressure hydrogen using conventional (CS) and tubular specimens (TS). For both specimen types, 0.2% yield strength and ultimate tensile strength were comparable. In reference atmosphere, reduction of area (RA) of CS was higher compared to TS, whereas in gaseous high pressure hydrogen RA of CS was lower compared to TS. The mean deviation between RA of TS and RA of CS is 11% for specimens tested in reference atmosphere and 10% for specimens tested in H 2 gas. In addition, given the diverse range of steels investigated here, the results shed some light on trends about the influence of microstructure on hydrogen effects. [Display omitted] • Twenty-two steels were tensile tested in high-pressure gaseous hydrogen using conventional (CS) and tubular specimens (TS). • For both specimen types, 0.2% yield strength and ultimate tensile strength were comparable. • In reference atmosphere, reduction of area (RA) of CS was higher compared to TS. • In gaseous high pressure hydrogen RA of CS was lower compared to TS. [ABSTRACT FROM AUTHOR]

When the cocoa pod husk (CPH) is used and processed, two types of flour were obtained and can be differentiated by particle size, fine flour (FFCH), and coarse flour (CFCH) and can be used as a possible reinforcement for the development of bio-based composite materials. Each flour was obtained from chopping, drying by forced convection, milling by blades, and sieving using the 100 mesh/bottom according to the Tyler series. Their physicochemical, thermal, and structural characterization made it possible to identify the lower presence of lignin and higher proportions of cellulose and pectin in FFCH. Based on the properties identified in FFCH, it was included in the processing of thermoplastic starch (TPS) from the plantain pulp (Musa paradisiaca) and its respective bio-based composite material using plantain peel short fiber (PPSF) as a reinforcing agent using the following sequence of processing techniques: extrusion, internal mixing, and compression molding. The influence of FFCH contributed to the increase in ultimate tensile strength (7.59 MPa) and higher matrix–reinforcement interaction when obtaining the freshly processed composite material (day 0) when compared to the bio-based composite material with higher FCP content (30%) in the absence of FFCH. As for the disadvantages of FFCH, reduced thermal stability (323.57 to 300.47 °C) and losses in ultimate tensile strength (0.73 MPa) and modulus of elasticity (142.53 to 26.17 MPa) during storage progress were identified. In the case of TPS, the strengthening action of FFCH was not evident. Finally, the use of CFCH was not considered for the elaboration of the bio-based composite material because it reached a higher lignin content than FFCH, which was expected to decrease its affinity with the TPS matrix, resulting in lower mechanical properties in the material. [ABSTRACT FROM AUTHOR]

The thermal properties, microstructure, and mechanical properties of Fe-18Mn-3Ti (wt%) were investigated, focusing on the effects of different heat-treatment processes. Results revealed that the 450 °C warm-rolling sample (450 WR) exhibited promising mechanical properties. Specifically, this sample displayed a yield strength of 988 MPa, an ultimate tensile strength of 1052 MPa, and total elongation of 15.49%. Consequently, a favorable strength-ductility balance was achieved. The strain-hardening ability surpassed that of the cold rolling sample (CR). Microstructure analysis indicated the simultaneous occurrence of dynamic equilibrium between grain deformation and re-crystallization because of the co-influence of thermal and strain in the warm rolling process. This desirable mechanical property was attributed to the presence of a multi-phase (α-martensite, austenite, and ε-martensite) and heterogeneous microstructure. The improvement of ultimate tensile strength was based on grain refinement, grain co-deformation, and the transformation-induced plasticity (TRIP) effect in the early stage of plastic deformation (stage Ⅰ). The improvement of ultimate elongation (TEL) was ascribed to the TRIP effect in the middle stage of plastic deformation (stage Ⅱ). [ABSTRACT FROM AUTHOR]

The primary focus of the current paper centers on the microstructures and mechanical properties exhibited by a Ti-30Nb-12Zr-5Ta-2Sn-1.25Fe (wt. %) (TNZTSF) alloy that has been produced through an intricate synthesis process comprising cold-crucible induction in levitation, carried out in an atmosphere controlled by argon, and cold-rolling deformation (CR), applying systematic adjustments in the total deformation degree (total applied thickness reduction), spanning from 10% to 60%. The microstructural characteristics of the processed specimens were investigated by SEM and XRD techniques, and the mechanical properties by tensile and microhardness testing. The collected data indicate that the TNZTSF alloy's microstructure, in the as-received condition, consists of a β-Ti phase, which shows polyhedral equiaxed grains with an average grain size close to 82.5 µm. During the cold-deformation processing, the microstructure accommodates the increased applied deformation degree by increasing crystal defects such as sub-grain boundaries, dislocation cells, dislocation lines, and other crystal defects, powerfully affecting the morphological characteristics. The as-received TNZTSF alloy showed both high strength (i.e., ultimate tensile strength close to σUTS = 705.6 MPa) and high ductility (i.e., elongation to fracture close to εf = 11.1%) properties, and the computed β-Ti phase had the lattice parameter a = 3.304(7) Å and the average lattice microstrain ε = 0.101(3)%, which are drastically influenced by the applied cold deformation, increasing the strength properties and decreasing the ductility properties due to the increased crystal defects density. Applying a deformation degree close to 60% leads to an ultimate tensile strength close to σUTS = 1192.1 MPa, an elongation to fracture close to εf = 7.9%, and an elastic modulus close to 54.9 GPa, while the computed β-Ti phase lattice parameter becomes a = 3.302(1) Å. [ABSTRACT FROM AUTHOR]

High speed sintering, a new powder-bed fusion additive manufacturing technology, utilizes infrared lights (IR) to intensely heat and melt polymer powders. The presence of defects such as porosity, which is associated with particle coalescence, is highly dependdent on the level of energy input. This study investigate the influcence of energy input on porosity and its subsequent effects on the mechanical properties and microstructures of PEBA parts. The parts were manufactured with a variety of lamp powers, resulting in a range of energy input levels spanning from low to high. Subsequebtly, they underwent testing using Archimedes' method, followed by tensile testing. The porosity, mechanical characteristics, and energy input exhibit a strong correlation; inadequate energy input was the primary cause of pore formation. Using the reduced IR light power resulted in the following outcomes: porosity, ultimate tensile strength, and elongation of 1.37%, 7.6 MPa, and 194.2%, respectively. When the energy input was further increased, the porosity was reduced to as low as 0.05% and the ultimate tensile strength and elongation were increased to their peak values of 233.8% and 9.1 MPa, respectively. [ABSTRACT FROM AUTHOR]

For practicable elastomeric polyethylene, achieving high catalyst thermal stability and activity, along with precise control of polymer properties such as branching density, molecular weights, and distribution, is crucial but challenging. In this study, two sets of symmetrical α-diimine nickel complexes, each comprising four nickel bromide or chloride complexes, were synthesized and investigated their performance for ethylene polymerization under various reaction conditions. Upon activation with either Et2AlCl or MMAO cocatalysts, these complexes displayed not only high activity but also generated high molecular weight polyethylenes with controlled polydispersity and a substantial number of branches. The catalyst with the least steric hindrance displayed the remarkable high activity (up to 1.2×107 g·mol−1·h−1). Notably, nickel bromides demonstrated higher activity compared to their chloride counterparts. The investigation into the effect of reaction temperature on catalytic performance revealed that NiBrMe-MMAO system displayed high thermal stability (activity up to 2.51×106 g·mol−1·h−1 at 100 °C) and consistently yielded high polymer molecular weights with narrow polydispersity over a broad temperature range of 30–100 °C. Of significant note, mechanical analysis of the resulting polyethylene demonstrated excellent ultimate tensile strength and high strain at break. Particularly, the polyethylene sample prepared at 100 °C exhibited ultimate tensile strength up to 10 MPa with 1863% maximum strain at break and a strain recovery of up to 54.9% after ten cycles at a fixed strain of 300%, indicating excellent material properties of prepared thermoplastic polyethylene elastomers (TPE). [ABSTRACT FROM AUTHOR]

This study proposed the direct extrusion and continuous-shear deformation (DECS) process for the co-extrusion of Mg-AZ31B/Al 6063, aiming to prepare high-plasticity Mg/Al composite sheets. The effect of extrusion temperature on the microstructure and mechanical properties of the Mg/Al composite sheet was systematically studied. The results show that Mg/Al composite sheets with no voids or cracks at the interface were successfully prepared by the DECS process. The microstructure of the Mg layer at different extrusion temperatures primarily consists of equiaxed fine grains, with grain sizes of 7.29 μm, 8.98 μm, and 9.88 μm at 330℃, 360℃, and 390℃, respectively. The Mg layer exhibits a typical extrusion texture, with the c-axis of most grains parallel to the transverse direction (TD). With the increase in extrusion temperature, the c-axis of some grains deviates from the TD toward the normal direction (ND). The Al layer mainly consists of elongated deformed grains and fine dynamically recrystallized (DRXed) grains distributed along the extrusion direction (ED). The AZ31 Mg alloy with refined grains maintains the ultimate tensile strength of the Mg/Al composite sheet, while the Al matrix enhances its plasticity. At 330℃, the Mg/Al composite sheet shows an ultimate tensile strength of 244.48 MPa ± 4.35 and an elongation of 39.42% ± 0.06. The influence of the bonding layer thickness on the shear and tensile properties of the composite sheet was studied, revealing that increasing the bonding layer thickness reduces the shear strength of the Mg/Al composite sheet but positively affects its tensile strength. [ABSTRACT FROM AUTHOR]

The present research aims to investigate the combined influence of arc current and travel speed in terms of heat input during tungsten inert gas (TIG) welding and examine it through microstructural, mechanical, and wear characterizations. An automated welding setup was employed to fabricate the dissimilar AA6061-T6 and AA7075-T6 aluminum joints in a butt configuration. Macro and micrographic inspections were also conducted and investigated the changes across the weld cross-section with respect to heat input. Tensile, Charpy impact, residual stress, and wear tests were performed to examine the quality and strength of the joint. The results revealed that the joints with increased heat input displayed higher ultimate tensile strength, impact toughness, residual stress, and wear resistance. The consistent distribution of intermetallic phases and the fine equiaxed grains with minimal porosity development are probably responsible for it. However, excessive heat input caused reversion phenomena, coarser grains, and significant porosities, which reduced the tensile strength, impact toughness, and wear resistance of the joint. The welded sample S-3, having a welding current of 145 A, a travel speed of 78 mm/min, and a heat input of 1.67 kJ/mm, exhibited the highest ultimate tensile strength of 178 MPa, the largest elongation of 12.6%, the highest impact toughness of 13 J, and the lowest wear rate of 34 µm, along with a compressive residual stress of 60 MPa at the weld centre. The analysis of tensile and impact-fractured surfaces using SEM and EDS analyses validated the experimental results. [ABSTRACT FROM AUTHOR]

The friction stir welding (FSW) method was used to weld B4C reinforced AA 5083 metal matrix composites in this study. By coating titanium nitride (TiN), aluminium chromium nitride (AlCrN), and diamond-like carbon (DLC) to a thickness of 4 microns, three FSW tools with square pin profiles were developed and the friction coefficients of 0.69, 0.32, and 0.2 were maintained. At three levels, the process factors such as tool rotating speed, transverse feed, and axial force were examined. For each tool, 15 samples were made using the central composite design. The influence of the friction coefficient on ultimate tensile strength, microstructural features, and tool condition was studied, and the flower pollination algorithm (FPA) technique was used to find the best process parameters for obtaining maximum ultimate tensile strength of FSW joints. The improved tensile strength of FSW joints was verified using a validation test. The coating has a considerable influence on the ultimate tensile strength, microstructure, and tool condition, according to the results of the tool's friction coefficient. The results on the prediction of strength using the fuzzy clustering technique showed that the technique is effective in predicting the tensile strength values, with the root mean square error (RSME) of TiN, AlCrN, and DLC being 0.0027, 0.0016, and 0.0015, respectively, and the low RSME indicating that the prediction based on the fuzzy subtractive clustering technique is perfect and effective. [ABSTRACT FROM AUTHOR]

AbstractIn the present investigation, the low hydrogen ferrite consumable weldment (weldment-1) and austenitic stainless steel consumable weldment (weldment-2) of rolled and homogenous armor steel (RHA) have been prepared with manual metal arc welding (MMAW). Further, the influence of weldments (weldment-1 and weldment-2) microstructure on the dynamic fracture toughness (J1d), strength, ductility and hardness has been evaluated and compared. The three different approaches have been utilized to estimate J1d for RHA weldments. Further, all three approaches’ outcomes have been compared with the elastic-plastic fracture mechanics (EPFM) approach through Jp-R curve. The results revealed that weldment-1 (yield strength 504.24 MPa and ultimate tensile strength 763.03 MPa) exhibited 26.93 and 25.07% more yield and tensile strength respectively than weldment-2 (yield strength 384.55 MPa and ultimate tensile strength 593.05 MPa). Further, the elongation of weldment-2 (elongation 42%) is 26.72% more than weldment-1 (elongation 32.10%). The joint efficiency and fusion zone hardness of weldment-1 are 5.85 and 57.56%, respectively more than weldment-2. The EPFM approach has good agreement with the correction factor approach (approach 2) and the compliance change rate approach (approach 3) with less than 7% difference in the estimation of dynamic fracture toughness of base metal and weldments (weldment-1 and weldment-2). Further, the percentage difference between maximum load point approach (approach 1) and the EPFM approach is more than 15% difference. The fractographic investigation confirms the ductile fracture in all under-investigated materials. [ABSTRACT FROM AUTHOR]

Biopolymer matrices has been synthesized on the basis of ED-20 epoxy resin and soybean oil (SbO) bearing cyclocarbonate and epoxy groups. Mono(cyanoethyl)diethylenetriamine (UP) and tris(2-hydroxyethyl)amine (TEA) were used as hardeners. Chemical structure, mechanical properties, thermo-oxidative resistance of the samples and their changes after contact with distilled water, alkaline or acidic environment were studied. By means of ATR-FTIR the possible formation of H-NIPU (hybrid non-isocyanate polyurethane) fragments between cyclocarbonate groups of SbO and amino groups of the hardener was demonstrated. Influence of the curing mode and the type of hardener on water absorption, chemical and thermal oxidation resistance of the developed biopolymer matrices was thoroughly investigated. UP-based biopolymer matrices showed water and alkali resistance similar to the ones of neat epoxy polymers, while TEA-based biopolymer matrices showed better resistance to the acidic medium. The thermo-oxidative stability of the chosen samples was revealed by the TGA method in an air atmosphere. It was demonstrated that epoxy polymer cured with TEA hardener were more stable than the one cured with UP hardener. The similar dependence is observed for biopolymer matrices based on TEA hardener. At the same time, the curing mode has almost no effect on ultimate tensile strength value of the samples with ED-20/UP composition. However, the addition of functionalized SbO to the epoxy matrix cured with both TEA and UP hardeners increases the ultimate tensile strength values regardless of the type of oil functionalization. As expected, all biopolymer matrices exhibited higher ultimate tensile strength compared with unmodified epoxy polymers, which provides the possibility of their further application to obtain multi-layered bioplastics. [ABSTRACT FROM AUTHOR]

The effects of 0.1 wt.% Ca addition, heat treatment, and SPD processing using the MaxStrain module of the Gleeble thermomechanical simulator on the microstructure, mechanical properties, and electrical conductivity of Cu–0.7Mg (wt.%) alloy were investigated in this work. The binary alloy exhibited a single-phase microstructure, whereas the ternary alloy featured uniform dispersion of Cu5Ca intermetallic particles inside the grains as well as on grain boundaries. These particles resulted in an average hardness that was 33% higher than that of the binary alloy, as well as 13% higher yield strength and 13% higher ultimate tensile strength. The heat treatment process not only enhanced the yield strength and ultimate tensile strength of the samples, but also resulted in the partial spheroidization of Cu5Ca particles within the microstructure of the ternary alloy, resulting in its improved ductility. Following MaxStrain processing, ternary samples exhibited a smaller grain size and a higher fraction of high-angle grain boundaries than binary samples, which was attributed to the vital role of Cu5Ca intermetallic particles in hindering the dislocation motion during deformation. MaxStrain-processed samples exhibited marginally lower electrical conductivities than their initial counterparts; yet, all MaxStrain-processed samples satisfied the electrical conductivity threshold for classification as HSHC Cu alloys. [ABSTRACT FROM AUTHOR]

In this study, concurrent enhancements in both strength and ductility of the Al-2Li-2Cu-0.5Mg-0.2Zr cast alloy (hereafter referred to as Al-Li) were achieved through an optimized forming process comprising ultrasonic treatment followed by squeeze casting, coupled with the incorporation of Sc. Initially, the variations in the microstructure and mechanical properties of the Sc-free Al-Li cast alloy (i.e., alloy A) during various forming processes were investigated. The results revealed that the grain size in the UT+SC (ultrasonic treatment + squeeze casting) alloy was reduced by 76.3% and 57.7%, respectively, compared to those of the GC (gravity casting) or SC alloys. Additionally, significant improvements were observed in its compositional segregation and porosity reduction. After UT+SC, the ultimate tensile strength (UTS), yield strength (YS), and elongation reached 235 MPa, 135 MPa, and 15%, respectively, which were 113.6%, 28.6%, and 1150% higher than those of the GC alloy. Subsequently, the Al-Li cast alloy containing 0.2 wt.% Sc (referred to as alloy B) exhibited even finer grains under the UT+SC process, resulting in simultaneous enhancements in its UTS, YS, and elongation. Interestingly, the product of ultimate tensile strength and elongation (i.e., UTS × EL) for both alloys reached 36 GPa•% and 42 GPa•%, respectively, which is much higher than that of other Al-Li cast alloys reported in the available literature. [ABSTRACT FROM AUTHOR]

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]

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]

AbstractThis study explored the effect of friction stir processing (FSP) on tungsten inert gas (TIG)-welded AA6061-T6 and AA7075-T6 joints by utilizing three different tool pin geometries, namely simple cylinder (SC), threaded cylinder with triflat faces (THF), and simple square (SS). The metallurgical aspects of unprocessed and processed weld regions were analyzed and correlated with the ultimate tensile strength, impact toughness, and microhardness properties. Results revealed that the post-FSP with a THF pin transformed the coarse dendritic structures (AGS of 34.55 µm) of the TIG weld into equiaxed fine structures (AGS of 3.51 µm) and increased the UTS, impact toughness, and microhardness by 71.51%, 95.40%, and 72.46%, respectively. The joint processed with the THF pin resulted in the highest ultimate tensile strength of 279 MPa, impact toughness of 15.02 J, and microhardness of 116.13 HV in the nugget region compared to the other two pin geometries. The highest joint properties of THF pin were attributed to the formation of fine grain structures in the nugget region, high effective strain and heat generation, improved material flow, and the decimation of intermetallic precipitates with their uniform dispersion in the nugget region. The tensile fractured surface of the TIG weldment had noticeable macro voids and coarse dimples with some rough cleavage facet in the fusion region, resulting in a brittle mode of failure. However, the tensile fractured surface of TIG + FSP weldments showed ductile failure due to the presence of fine and deep dimples with tear ridges without any void. [ABSTRACT FROM AUTHOR]

This study demonstrates the feasibility of using Irvingia gabonensis shell particulates (IGSp) as alternative reinforcing materials in the development of aluminium-based composites. In this experimental study, the microstructure, phase composition, and mechanical behaviour of Al-10Zn-1.63Si/xIGSp (wt%, x = 1, 3, 5 and 7) composites were investigated. The Al-10Zn-1.63Si based composites were fabricated using the stir-casting technique. Different weight percentages (1, 3, 5 and 7) of IGSp were added to the Al-10Zn-1.63Si matrix. The chemical constituents of the IGSp were determined using X-ray fluorescence (XRF). The grain characteristics and phase(s) compositions were determined using Scanning Electron Microscopy (SEM) and X-ray diffractometer (XRD). The ultimate tensile strength, hardness, and impact strength of the developed composites were also determined. The SEM and XRD results revealed the presence of different phases: aluminium phosphate (Al16P16O64), gahnite (ZnAl2O4), andalusite (Al2SiO5), Quartz (SiO2) and aluminium silicate (Al2O3.5.SiO2). Results show that addition of IGSp led to an increase in ultimate tensile strength, with the highest value (128 MPa) obtained at 3 wt% IGSp. The hardness of the composites increased with increasing concentrations of IGSp, reaching a maximum value of 285 HV after adding 7 wt% IGSp. The impact strength improved with the addition of IGSp, with the highest value (30 J) obtained at 1 wt% IGSp. The improvements in mechanical properties were attributed to the dispersion of three major phases: aluminium silicate (Al2O3.54.SiO2), Al16P16O64 and Al2O3.54.SiO2. These phases contributed to the enhanced strength and hardness of the composites. The study noted a sudden decrease in ultimate tensile strength with higher concentrations of IGSp due to the increase in the intensities of Al16P16O64 and precipitation of hard but brittle new phase; Al2Si60.6O126.33. The study concludes that IGSp has the potential to serve as an alternative reinforcing material for aluminium-based composites. [ABSTRACT FROM AUTHOR]

This study focuses on evaluating the fatigue life performance of 3D-printed polymer composites produced through the fused deposition modelling (FDM) technique. Fatigue life assessment is essential in designing components for industries like aerospace, medical, and automotive, as it provides an estimate of the component's safe service life during operation. While there is a lack of detailed research on the fatigue behaviour of 3D-printed polymer composites, this paper aims to fill that gap. Fatigue tests were conducted on the 3D-printed polymer composites under various loading conditions, and static (tensile) tests were performed to determine their ultimate tensile strength. The fatigue testing load ranged from 80% to 98% of the total static load. The results showed that the fatigue life of the pressed samples using a platen press was significantly better than that of the non-pressed samples. Samples subjected to fatigue testing at 80% of the ultimate tensile strength (UTS) did not experience failure even after 1 million cycles, while samples tested at 90% of UTS failed after 50,000 cycles, with the failure being characterized as splitting and clamp area failure. This study also included a lap shear analysis of the 3D-printed samples, comparing those that were bonded using a two-part Araldite glue to those that were fabricated as a single piece using the Markforged Mark Two 3D printer. In summary, this study sheds light on the fatigue life performance of 3D-printed polymer composites fabricated using the FDM technique. The results suggest that the use of post-printing platen press improved the fatigue life of 3D-printed samples, and that single printed samples have better strength of about 265 MPa than adhesively bonded samples in which the strength was 56 MPa. [ABSTRACT FROM AUTHOR]

Additive Manufacturing (AM) processes are known as revolutionary manufacturing processes that fabricate a part using a 3D model layer upon layer. These techniques gained more attention from various industries due to their advantages like low waste material. Also, these processes can produce any part with high degrees of complexity in a short period of time. The Fused Deposition Modeling (FDM) process is a material extrusion-based technique which works by extruding a fine molten polymeric filament through a heated nozzle on the heated platform named printer bed. In this method, some important manufacturing parameters play a crucial role in controlling the mechanical properties and quality of the final fabricated part. However, all printed specimens through the FDM process should be tested based on the standards under some critical circumstances. Thus, in the current research paper, five and three test speeds are considered in tensile and fracture testing procedures, respectively to evaluate how these speeds can affect the mechanical and mode I fracture properties. Also, as the FDM specimens present elastic–plastic behavior, the critical value of J-integral is assumed as a fracture assessment and calculated from the finite element analysis. Among the mechanical properties, ultimate tensile strength is affected significantly by the test speed. For instance, the ultimate tensile strength of FDM specimens is 39.02, 38.58, 42.33, 48.09, and 52.11 for test speeds of 2, 4, 6, 8, and 10 mm/min, respectively. But vice-versa results are detected for the mode I fracture behavior and corresponding values of J for the FDM-PLA specimens. Finally, experimental and numerical results together with comprehensive discussions about the considered speeds and obtained results are reported. [ABSTRACT FROM AUTHOR]

Mg alloys with excellent high-temperature mechanical properties are urgently desired to meet the design requirements of new-generation aircraft. Herein, novel cast Mg-10Gd-2Y-0.4Zn-0.2Ca-0.5Zr-xAg alloys were designed and prepared according to the advantages of multi-component alloying. The SEM and XRD results revealed that the as-cast microstructures contained α-Mg grains, β, and Zr-containing phase. As Ag rose from 0 wt.% to 2.0 wt.%, the grain size was refined from 40.7 μm to 33.5 μm, and the β phase significantly increased. The TEM observations revealed that the nano-scaled γ′ phase could be induced to precipitate in the α-Mg matrix by the addition of Ag. The stacking sequence of lamellar γ′ phases is ABCA. The multiple strengthening phases, including β phase, γ′ phases, and Zr-containing particles, were effectively tailored through alloying and synergistically enhanced the mechanical properties. The ultimate tensile strength increased from 154.0 ± 3.5 MPa to 231.0 ± 4.0 MPa at 548 K when Ag was added from 0 to 2.0 wt.%. Compared to the Ag-free alloy, the as-cast alloy containing 2.0 wt.% Ag exhibited a minor reduction in ultimate tensile strength (7.0 ± 4.0 MPa) from 498 K to 548 K. The excellent high-temperature performance of the newly developed Mg-RE-Ag alloy has great value in promoting the use of Mg alloys in aviation industries. [ABSTRACT FROM AUTHOR]

(TiH2 + ScH3)/Al-Mg composite powders with different Ti contents were produced by ball milling. These composite powders were fabricated to cube and cuboid shape samples via a laser powder bed fusion process with optimal processing parameters. The TiH2 and ScH3 particles underwent dehydrogenation during the laser powder bed fusion process, and these composite powders ultimately formed Al-Mg-Sc-Ti alloys. The relative density, printability, microstructure, hardness and tensile properties of these alloy samples were investigated. The results show that these Al-Mg-Sc-Ti alloys have lower hot-crack sensitivity, having fine equiaxed grains. An Al18Mg3(Ti,Sc)2 intermetallic phase and in situ L12-Al3(Sc,Ti) precipitations formed during the laser powder bed fusion process, which is beneficial for nucleation and dispersion strengthening. The ultimate tensile strength of the Al-Mg-0.7Sc-1.0Ti alloy was 313.6 MPa with an elongation of 6.6%. During the hot isostatic pressing treatment, most of the Mg element precipitated from the matrix and changed the Al3(Sc,Ti) into a Al18Mg3(Ti,Sc)2 precipitate completely. The Al-Mg-Sc-Ti alloys were nearly fully dense after the hot isostatic pressing treatment and exhibited better mechanical properties. The ultimate tensile strength of the Al-Mg-0.7Sc-1.0Ti was 475 MPa with an elongation of 8.5%. [ABSTRACT FROM AUTHOR]

This study presents the adoption of the grey relational analysis (GRA) method and an objective weighting criterion (CRITIC) to select the best printing parameters (laser power, scan speed, hatch distance, and layer thickness) for achieving the minimum surface roughness. At the same time, the material hardness, ultimate tensile strength, elongation at break, and relative density are maximized and followed by a complementary residual stress assessment of selected samples. A Box Behnken experimental design of 27 experiments with a factor variation at three levels was chosen to characterize the laser-based powder bed fusion process of 316L stainless steel. This study is guided by a multi-criteria decision-making (MCDM) approach to simultaneously consider all the factors that yield the most proper printing parameters. Due to the multi-directionality of the problem analysed, four additional MCDM methods are also employed to avoid any limitations in the solutions. The correlation between these techniques was evaluated through Spearman's coefficient. Additionally, the reliability of the optimal printing outcomes was experimentally confirmed, improving the final surface quality by 8.17%, the elongation and ultimate tensile strength by 4.62% and 4.35%, respectively. Moreover, the residual stresses obtained were all of compressive nature, and their magnitude is comparable with those already published works. [ABSTRACT FROM AUTHOR]

In this research, effective utilization of agro waste breadfruit seed husk ash particle (SHA) as reinforcement purpose in LM25 alloy matrix enhanced with the inclusions of 3, 6, and 9wt% of graphite (Gr) nanoparticle (50nm) via squeeze cast liquid processing executed with 200MPa applied compressive pressure. This developed cast examined LM25 alloy and its composites for density, percentage of porosity, microstructure, ultimate tensile strength, abrasion, and corrosion behaviour. From the experimental result, the LM25/10wt% SHA/9wt% Gr hybrid nanocomposite has low density (2.554g/cc), an excellent ultimate tensile strength of (181±1.8 MPa), superior abrasion resistance (0.332mg/m) under 40N load at 0.75m/sec, and good corrosion resistance (0.00382mm/year) compared to cast LM25 alloy. The inclusions of SHA and Gr proved their presence in LM25 alloy has good mechanical strength and maximum abrasion and corrosion resistance to overcome the drawbacks of conventional stir-casted LM25 alloy, which is poor wear resistance. [ABSTRACT FROM AUTHOR]

Purpose: In recent years, additive manufacturing (AM) has started to be used for manufacturing real functional parts and assemblies for critical applications in aerospace, automotive, and machinery industries. Most complex or assembled parts require internal features (IF) such as holes, channels, slots, or guides for locational and mating requirements. Therefore, it is critical to understand and compare the structural and mechanical properties of additively manufactured and conventionally machined IFs. Design/methodology/approach: In this study, mechanical and microstructural properties of Inconel 718 (Inc718) alloy internal features, manufactured either as-built with AM or machining of additively manufactured (AMed) part thereafter were investigated. Findings: The results showed that the average ultimate tensile strength (UTS) of additively manufactured center internal feature (AM-IF) is almost analogous to the machined internal feature (M-IF). However, the yield strength of M-IF is greater than that of AM-IF due the greater surface roughness of the internal feature in AM-IF, which is deemed to surpass the effect of microstructure on the mechanical performance. The results of digital image correlation (DIC) analysis suggest that AM-IF and M-IF conditions have similar strain values under the same stress levels but the specimens with as built IF have a more locally ductile region around their IF, which is confirmed by hardness test results. But this does not change global elongation behavior. The microstructural evolution starting from as-built (AB) and heat-treated (HT) samples to specimens with IF are examined. The microstructure of HT specimens has bimodal grain structure with d phase while the AB specimens display a very fine dendritic microstructure with the presence of carbides. Although they both have close values, machined specimens have a higher frequency of finer grains based on SEM images. Originality/value: It was shown that the concurrent creation of the IF during AM can provide a final part with a preserved ultimate tensile strength and elongation but a decreased yield strength. The variation in UTS of AM-IF increases due to the surface roughness near the internal feature as compared to smooth internal surfaces in M-IF. Hence, the outcomes of this study are believed to be valuable for the industry in terms of determining the appropriate production strategy of parts with IF using AM and postprocessing processes. [ABSTRACT FROM AUTHOR]