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Resistance spot welding (RSW) is considered as predominant welding technique that is used in the manufacturing of modern automobile structure. The automobile structure is made of high strength steel which is preferred by the car industry companies due to its high strength-weight ratio. This work presents an optimization method for RSW of high-strength low-alloy steel DOCOL 500 LA. Tensile test and microstructure analysis for base material (BM) were carried out to get the mechanical properties of BM and to specify the rolling direction. Taguchi method, high efficiency technique, was applied using Minitab19 software to achieve the optimization process. Tensile shear test was carried out to evaluate the strength of welding nugget, absorbed energy and failure mode. The results showed that the optimum parameters were 8,800 A for the current, 30 cycles for the welding time and 2,230 N for the electrode force and two types of failure modes could be observed which were interfacial and full pullout mode.

This study aims to achieve in situ-formed pure Ti and Ti6Al4V coatings on 316L stainless steel through hot pressing and examine their wear and corrosion properties thoroughly in two simulated body fluids: physiological serum (0.9% NaCl) and Hanks' solution. The sintering and diffusion bonding process was conducted at 1050 °C under a uniaxial pressure of 40 MPa for 30 min in a vacuum environment of 10−4 mbar. Following sintering, in situ-formed pure Ti and Ti6Al4V coatings, approximately 1000 µm thick, were produced on 316L substrates approximately 3000 µm in thickness. The mean hardness of 316L substrates, pure Ti, and Ti6Al4V coatings are around 165 HV, 170 HV, and 420 HV, respectively. The interface of the stainless steel substrate and the pure Ti and Ti6Al4V coatings exhibited no microstructural defects, while the interface exhibited significantly higher hardness values (ranging from 600 to 700 HV). The coatings improved corrosion resistance in both electrolytes compared to the 316L substrate. Wet wear tests revealed reduced friction coefficients in 0.9% NaCl relative to Hanks' solution, highlighting the chemical interactions between the material surface and the electrolyte type and the significance of tribocorrosion in biocoatings. [ABSTRACT FROM AUTHOR]

This study aimed to develop an alternative surface hardening technique for low-carbon steel alloy type 20Ch using plasma electrolytic oxidation (PEO). The surface hardening of 20Ch alloy steel samples was achieved through PEO in a Na2CO3 electrolyte solution. Optimal processing parameters were determined experimentally by measuring voltage and applied current. Quenching was performed in the electrolyte stream, and plasma was ionised through excitation. A mathematical model based on thermal conductivity equations and regression analysis was developed to relate the key parameters of the hardening process. The results from both the experimental and mathematical models demonstrated that PEO significantly reduces hardening time compared to traditional methods. The microstructural images revealed the transformation of the coarse-grained pearlite–ferrite structure into quenched martensite. Vickers microhardness tests indicated a substantial increase in surface hardness after PEO treatment, compared to the untreated samples. The major advantages of PEO include lower energy consumption, high quenching rates, and the ability to perform localised surface treatments. These benefits contribute to overall cost reduction, making PEO a promising surface hardening method for various industrial applications. [ABSTRACT FROM AUTHOR]

This study addresses the challenge of accurately predicting corrosion rates and estimating the remaining life of underground gas pipelines, which is complicated by the complex interaction of physical factors and environmental conditions. Traditional models are inadequate in capturing these variables, leading to less reliable predictions, which this study aims to address by developing a more accurate and optimized artificial neural network (ANN) model. This study focuses on predicting corrosion rates and estimating the remaining life of underground gas pipelines using ANNs implemented in MATLAB. It incorporates both physical factors, such as maximum corrosion depth and pipe thickness, and environmental variables such as moisture, soil resistivity, and chloride concentration. The analysis identified corrosion depth and wall thickness as significant contributors, influencing material integrity by 20% and 16%, respectively. The optimal ANN model, with a Levenberg-Marquardt structure and one hidden layer of 10 neurons, achieved superior accuracy, with an MSE of 0.038 and R² of 0.9998. The study addresses the challenge of accurately predicting corrosion rates and remaining life in underground gas pipelines by developing an optimised ANN model. Its contribution lies in creating a highly accurate prediction tool that outperforms traditional models and enables more informed decisions for pipeline maintenance and safety. [ABSTRACT FROM AUTHOR]

Purpose: The research aims to investigate the impact of thermo-mechanical aging on SBR under cyclic-loading. By conducting experimental analyses and developing a 3D finite element analysis (FEA) model, it seeks to understand chemical and physical changes during aging processes. This research provides insights into nonlinear mechanical behavior, stress softening and microstructural alterations in SBR compounds, improving material performance and guiding future strategies. Design/methodology/approach: This study combines experimental analyses, including cyclic tensile loading, attenuated total reflection (ATR), spectroscopy and energy-dispersive X-ray spectroscopy (EDS) line scans, to investigate the effects of thermo-mechanical aging (TMA) on carbon-black (CB) reinforced styrene-butadiene rubber (SBR). It employs a 3D FEA model using the Abaqus/Implicit code to comprehend the nonlinear behavior and stress softening response, offering a holistic understanding of aging processes and mechanical behavior under cyclic-loading. Findings: This study reveals significant insights into SBR behavior during thermo-mechanical aging. Findings include surface roughness variations, chemical alterations and microstructural changes. Notably, a partial recovery of stiffness was observed as a function of CB volume fraction. The developed 3D FEA model accurately depicts nonlinear behavior, stress softening and strain fields around CB particles in unstressed states, predicting hysteresis and energy dissipation in aged SBRs. Originality/value: This research offers novel insights by comprehensively investigating the impact of thermo-mechanical aging on CB-reinforced-SBR. The fusion of experimental techniques with FEA simulations reveals time-dependent mechanical behavior and microstructural changes in SBR materials. The model serves as a valuable tool for predicting material responses under various conditions, advancing the design and engineering of SBR-based products across industries. [ABSTRACT FROM AUTHOR]

This study investigates the in vitro biocompatibility, corrosion resistance, and adhesion strength of a gas abrasive-treated Ti6Al4V alloy, alongside microplasma-sprayed titanium and tantalum coatings. Employing a novel approach in selecting microplasma spray parameters, this study successfully engineers coatings with tailored porosity, roughness, and over 20% porosity with pore sizes up to 200 μm, aiming to enhance bone in-growth and implant integration. This study introduces an innovative methodology for quantifying surface roughness using laser electron microscopy and scanning electron microscopy, facilitating detailed morphological analysis of both the substrate and coatings. Extensive evaluations, including tests for in vitro biocompatibility, corrosion resistance, and adhesive strength, revealed that all three materials are biocompatible, with tantalum coatings exhibiting superior cell proliferation and osteogenic differentiation, as well as the highest corrosion resistance. Titanium coatings followed closely, demonstrating favorable osteogenic properties and enhanced roughness, which is crucial for cell behavior and attachment. These coatings also displayed superior tensile adhesive strengths (27.6 ± 0.9 MPa for Ti and 28.0 ± 4.9 MPa for Ta), surpassing the ISO 13179-1 standard and indicating a robust bond with the substrate. Our findings offer significant advancements in biomaterials for medical implants, introducing microplasma spraying as a versatile tool for customizing implant coatings, particularly emphasizing the superior performance of tantalum coatings in terms of biocompatibility, osteogenic potential, and corrosion resistance. This suggests that tantalum coatings are a promising alternative for enhancing the performance of metal implants, especially in applications demanding high biocompatibility and corrosion resistance. [ABSTRACT FROM AUTHOR]

This research aims to investigate the effect of the exfoliation corrosion exposure time on the mechanical properties, the strength and elongation, of friction stir welded Al–Li alloy type 2195-T8. The exfoliation corrosion test was performed using the exfoliation corrosion (EXCO) solution, based on ASTM G34. The samples were exposed to different exposure times 24, 48, 96, 192 and 384 h. The results showed that both the strength and elongation of the welded specimens—exposed to the exfoliation corrosion tests—were reduced. For example, the samples that were exposed to 384 h, their initial tensile strength and elongation were reduced by 13% and 17% respectively. The degradation process due to the exfoliation corrosion on the tensile strength was divided into three stages: fast (0–96 h: 443.7 MPa-416.3 MPa, the degraded rate was 0.29 MPa/h), steady (96–192 h: 416.3 MPa-413.4 MPa, the degraded rate was 0.03 MPa h ^−1 ) and medium rate (192–384 h: 413.4 MPa-386.7 MPa, the degraded rate was 0.14 MPa h ^−1 ). For the elongation, in general, the reduction was similar to the style of strength, but with different rates. The TEM images showed that this degradation was due to the dissolution of T _1 (Al _2 CuLi) and S′ (Al _2 CuMg) phase. Also, the corrosion products and their role of adherence on the surface of the tested specimens were investigated. An empirical equation p -t (mechanical properties-exposure time) was established to calculate the effect of exposure corrosion time on the performance of welded specimens.

Measurement to mitigate automotive emission varies from energy content modification of fuel to waste energy recovery through energy system upgradation. The proposed energy-averaged emission mitigation technique involves interfacing piston design exchange and gasoline–methanol blend replacement with traditional gasoline for low carbon high energy content creation. Here, we interlinked the CO, CO2, NOx, O2, and HC to different design exchanges of coated pistons through the available brake power and speed of the engine. We assessed the relative effectiveness of various designs and coating thicknesses for different gasoline–methanol blends (0%,5%,10%, and 15%). The analysis shows the replacement of 5%, 10%, and 15% by volume of gasoline with methanol reduces the fuel carbon by 4.167%, 8.34%, and 12.5%, respectively. The fuel characteristics of blends are comparable to gasoline, hence there is no energy infrastructure modification required to develop the same amount of power. The CO and HC reduced significantly, while CO2 and NOx emissions are comparable. Increasing the coating thickness enhances the surface temperature retention and reduces heat transfer. The Type_C design of the steel piston and type_A design of the AlSi piston show temperature retention values of 582 °C and 598 °C, respectively. Type_A and type_B pistons are better compared to type_C and the type_D piston design for emission mitigation due to decarbonization of fuel through gasoline-methanol blend replacement. Surface response methodology predicts Delastic, σvon Mises, and Tsurface with percentage errors of 0.0042,0.35, and 0.9, respectively. [ABSTRACT FROM AUTHOR]

Despite well‐controlled chlorination, no known operational outages and physicochemical parameters of the water indicating a slight tendency to form carbonate deposits, aged and internally uncoated pipelines may experience unexpected internal corrosion events that raise integrity concerns. A typical corrosion damage was investigated consisting of a single perforation covered by a corrosion product cap (CPC) approximately 5 cm in diameter and surrounded by a relatively dense population of blisters of approx. 1 cm in diameter covering shallow corrosion pits. It was observed on the inner wall of an aged on‐land water distribution pipeline after decades of corrosion‐free operation. A dense population of bacteria, sulphides and extracellular polysaccharide substances were detected in the CPC, but none at the pit bottom surrounding the perforation and within the blisters, but abundant fungi were observed on scanning electron microscopy images of the blister bottom. The morphology of the blisters suggests that the blister formation is due to the loss of adhesion of the corrosion product layer, which is influenced by the formation of spherulitic crystals. The Fourier transform infra‐red spectroscopy results suggest that the growth of these carbonate crystals is related to the adsorption of microbially generated carbonyl groups. The results support a likely scenario of the effect of biomineralization on the appearance of corrosion through the formation of blisters, which may provide a niche for microbes that eventually cause corrosion damage. [ABSTRACT FROM AUTHOR]

In this study, the corrosion performance of AA2014 aluminum alloy was enhanced by coating the alloy with a layer containing silica (SiC) that was formed by the plasma electrolytic oxidation (PEO) process. The PEO process was performed with different electrical parameters (frequency, current mode, and duty ratio) and both with and without SiC to investigate the microstructural and electrochemical differences in the coated samples produced from the process. The microstructure and composition of the PEO coatings were studied using X-ray diffraction (XRD) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS). A potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical behavior of the AA2014-PEO-coated samples. The potentiodynamic polarization showed that the SiC-PEO-coated samples had a significantly decreased corrosion rate (99.8%) compared with the uncoated AA2014 Al alloy. Our results showed that the coats containing SiC possessed a much higher corrosion resistance than both the uncoated AA2014 Al alloy (8,344,673%) and the SiC-free coatings, which possess low corrosion resistance, because of their higher chemical stability and more compact microstructure. [ABSTRACT FROM AUTHOR]

This study aims to investigate the effect of the processing parameters in plasma electrolytic oxidation (PEO) on the corrosion resistance of magnesium alloy type AZ91. The PEO coatings were prepared on the samples using alkaline‐based electrolyte. Both unipolar and bipolar, different frequencies and duty cycles were applied. Corrosion tests, using potentiodynamic polarization, linear and cyclic, and electrochemical impedance spectroscopy techniques, were applied on the as‐received and PEO coated samples. Scanning electron microscopy was used to investigate the surface morphology, for example, micropores, as well as to measure the thickness of the coated layer by changing the processing parameters. The results show that the size of micropores is interrelated to the duty cycle percentage and current polarities, as the higher frequency causes thinner coating layers, with fewer micropores, consequently higher corrosion resistance. In addition, increasing the duty cycle, a denser and more compact coating was obtained. The XRD results showed a missing peak of the α‐Mg phase in a PEO coated sample using bipolar, the highest frequency (1666 Hz), and the highest duty cycle (66.6%). The mils per year calculations showed that the PEO coated has a lower corrosion rate by at least 8 times than the as‐received alloy. [ABSTRACT FROM AUTHOR]

Municipal solid waste (MSW) contains plastic waste that can be used as a sustainable green substitute to reduce oil footprints, CO2 emissions, and environmental pollution. This study aims to recycle plastic waste by manufacturing wood-plastic composites and to improve its mechanical properties by using additives, coupling agents, and lubricants. These composites are prepared by mixing 40–70% of wood flour with 20–25% of a polymer matrix. Wood was degraded at 220 °C, and then the composites were processed at 50 °C. The manufacturing process carried out in the study involved wood waste meshing, drying, shredding, drying, trimming, filling, blending, compounding, and extrusion moulding. The compounding of composites was accomplished in twin-screw extruders. Once the mixture was uniformly mixed, its final shape was given by a two-step extrusion moulding. Previously, researchers aimed at enhancing the mechanical properties of the composites, but our research focus was to improve their durability for different industrial applications. The results suggest that the impact strength is 17 MPa with 50% of wood powder ratio while the maximum value for the tensile strength is 32.5 MPa. About 50% of an increase in wood powder resulted in 8.1% bending strength increase from 26.1 to 32.8 MPa. Reducing the plastic matrix and the wood-particles water swelling ratio resulted in better mechanical properties. The wood species also affected the mechanical properties with their excellent dimensional stability and less variability. A high proportion of wood fibre tends to increase its steady-state torque and viscosity. The mechanical properties against different wood-flour proportions indicate that composite materials exhibit superior water swelling behaviour and extrusion quality. [ABSTRACT FROM AUTHOR]