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High entropy alloys (HEAs), known for their multi-principal element composition, have attracted considerable interest in light of their unique mechanical and thermal properties. Among them, the AlCoCrFeNi HEA system has shown promising characteristics, but the influence of additional alloying elements on its performance remains a crucial area of study. This comprehensive review investigates the effects of incorporating supplementary elements into the core AlCoCrFeNi system on its microstructure and various properties. Furthermore, it explores how these alterations in microstructure impact the mechanical properties, corrosion and wear behavior of the HEA, emphasizing the potential to customize these properties through strategic alloying additions. Additionally, the review examines how varying the amounts of constituent elements in the AlCoCrFeNi system, without adding additional elements, influences the microstructure and phases formed, with the help of phase diagrams. This review offers valuable insights to researchers and engineers aiming to optimize AlCoCrFeNi HEAs for specific applications. [ABSTRACT FROM AUTHOR]

The ability to perform against extreme corrosion environments in stainless steel depreciates under challenging conditions in industrial applications. This can be resolved by employing surface modification techniques to modify the surface with the required characteristics. The present study investigates the outcomes of friction stir processing of SS304 with CoCrFeCuTi high entropy alloy (HEA) as reinforcement and the property enhancements post-annealing. The synthesized CoCrFeCuTi HEA exhibited irregular fragments with 17 µm mean particle size and body centred cubic (BCC) phase. The microstructure of the processed surface revealed ultra-refined grains with a uniform distribution of HEA filler. The microstructures of the samples annealed at 400°C, 550°C, 700°C and 850°C for 2 h also showed significant grain growth and grain refinements. The processed sample with HEA reinforcement annealed at 700°C exhibited enhanced microhardness and tensile strength by 63% and 0.88 times than that of the processed sample with HEA pre-annealing. The subsequent electrochemical corrosion test displayed better corrosion resistance for the HEA-processed and annealed sample. Hot corrosion tests at 900°C showcased excellent resistance for the HEA processed and annealed samples by 14.92%, 12.75%, and 14.83% against the samples pre-annealed under three different salt mixtures, and the corroded surface was analyzed. [ABSTRACT FROM AUTHOR]

Tetralin is an ortho-fused bicyclic hydrocarbon notable for its odour of a mixture of benzene and menthol and high boiling point. Its low vapor pressure has limited its study by far-infrared spectroscopy but vibrational data have been obtained through alternative methods such as single vibronic level fluorescence (SVLF) and high-temperature vapor-phase Raman spectra. Tetralin is of more than chemical interest because it is part of several biologically active compounds. Interestingly, tetralin is a structural element of the anthracycline antibiotics that are clinically applied in cancer chemotherapy owing to their DNA-intercalating activity. The tetralin ring is crucial in sertraline, an antidepressant, and other clinically relevant compounds, including antifungal, anti-Parkinsonian, and anti-inflammatory activity. A comprehensive overview of tetralin derivatives with their diverse biological activities and therapeutic potentials has been discussed in the review. It also encompasses the synthetic methodology for the synthesis of tetralin and its derivatives including hydrogenation, and cyclization through metal catalysts, and visible light. In addition, a green chemical synthetic technique such as supercritical fluid technology was discussed, which improves the production of tetralin. Apart from that, metabolic pathways and catabolism of tetralin in biological systems and drug delivery systems of tetralin have been discussed. The review underlines the importance of tetralin derivatives in medicinal chemistry and has future developmental potential in therapeutic applications. [ABSTRACT FROM AUTHOR]

The creation of new alloys with improved qualities has become essential in modern industries for high-performance materials. This work's main objective is to use vacuum arc melting (VAM) to synthesize two different high-entropy alloys (HEAs): AlCrFeNiCu and AlCrFeNiCo. The mechanical properties, phase composition, grain boundaries, and alloy composition of the HEAs were studied. The predominant crystal structure, the Body-Centred Cubic (BCC) phase was obtained for both alloys. Significantly, the Co-containing HEA showed a smaller particle size than the Cu-containing HEA, which led to a 14.21% increase in microhardness. It indicates that the Co-based HEA will likely perform better than the Cu-based HEA in applications prone to abrasion, and indentation, and requiring high hardness levels based on the observed microstructure and hardness parameters. According to wear surface morphology studies, main effects analysis and ANOVA show that increasing loads and sliding distances increase wear rate, whereas sliding velocity has less effect. The best wear rate-reducing parameters are 10 N, 0.5 m/s, and 500 m for Cu-containing HEAs, and the same can be predicted using regression analysis. The study categorizes the intricate worn surface structure by describing different surface properties and wear mechanisms, such as grooves, delamination, adhesive wear, and pitting. [ABSTRACT FROM AUTHOR]

The integrity of dissimilar Al-Ti welds during conventional friction stir welding (CFSW) is compromised by excessive material mixing, leading to thick intermetallic layers. Underwater friction stir welding (UWFSW) mitigates these effects by inhibiting material mixing due to lower thermal conditions. Scanning electron microscopy revealed substantial Ti particles, appearing as blocks and strips, within the stir zone during CFSW. Static recrystallization, driven by exothermic reactions between Ti blocks and the Al matrix, resulted in over 93% recrystallized grains along stir zone, 10.7% higher than in UWFSW. In contrast, UWFSW resulted in a finer dispersion of Ti particles with reduced density due to lower frictional heat. The average grain size at the Ti interface of CFSW was 1.0 μm, compared to 2.6 μm in UWFSW. The inhomogeneous distribution of Ti particles in CFSW led to uneven dislocation distribution and increased stress concentrations, while finer Ti particles in UWFSW promoted a uniform grain structure, enhancing joint strength to 267 MPa, 13.4% higher than CFSW. Additionally, the γ-fibre and basal fibre texture in UWFSW increased joint ductility. The study highlights UWFSW's effectiveness in joining dissimilar metals, offering significant advantages for industries such as aerospace and automotive. [ABSTRACT FROM AUTHOR]

The document is a correction notice for an article titled "Electrochemical and hot corrosion behaviour of annealed AlCoCrFeNi HEA coating over steel" published in Scientific Reports. The correction addresses errors in Figure 17(e) and Figure 18(b) of the original article, where incorrect figures were uploaded. The corrected version includes SEM images of the hot corroded surface and elemental mapping of the coated and annealed surface. The authors of the original article are N. Radhika, Niveditha Noble, and Adeolu Adesoji Adediran. [Extracted from the article]

High Entropy Alloys (HEAs) certainly stand out lately because of their uncommon mechanical properties and possible applications in different fields. Friction Stir Processing (FSP), a solid-state processing technique, has been displayed to upgrade the microstructure and mechanical properties of HEAs. This review article sums up the present status of-the-specialty of FSP applied to HEAs. The microstructural development and the processing parameters of FSP-treated HEAs are discussed and reviewed. The impacts of FSP on the grain structure, texture, and phase distribution of HEAs are featured. Moreover, the impact of FSP on the mechanical properties, like ultimate tensile strength, yield strength, microhardness, tribological behaviour, and corrosion properties of HEAs and HEA-reinforced metals is explored. Finally, possible applications and the difficulties and future headings of FSP applied to HEAs are examined. The review aims to give an outline of the recent progressions in the FSP of HEAs and inspire further research in this field. [ABSTRACT FROM AUTHOR]

Banana bract mosaic virus (BBrMV) infection results in characteristic reddish streaks on pseudostem and chlorotic spindle lesions on leaves leading to traveler's palm appearance and complete crop loss depending on the stage of infection in banana plants. Here, we discuss the influence of P. indica colonization (a beneficial fungal root endophyte) on BBrMV infection, specific viral component genes responsible for symptom development, chlorophyll and carotenoid biosynthesis, and degradation in BBrMV-infected banana plants. P. indica colonization significantly and substantially reduced the severity of Banana bract mosaic disease (BBrMD) in addition to increased growth, development and yield of banana plants. The percent disease incidence (PDI) of BBrMV ranges from 50 to 70 per cent in plants raised from suckers and from 58 to 92 per cent in TC plants under artificial inoculation. P. indica-colonized plants inoculated with BBrMV resulted in an enhanced plant height, root length, leaf width, and leaf length of 72, 88, 90, and 60 per cent, respectively, compared to BBrMV alone-infected banana plants along with the reduced disease severity. BBrMV infection showed a drastic decrease of chlorophyll a, chlorophyll b, and total chlorophyll contents by down-regulating chlorophyll biosynthesis (Chlorophyll synthase—CHLG) and upregulating chlorophyll degradation (Chlorophyllase—CLH1 and CLH2 and Pheophytin pheophorbide hydrolase—PPH) genes; and by up-regulating carotenoids biosynthesis (Phytoene synthases—PSY1 and PSY2) and down-regulating its degradation (Phytoene desaturase—PDS) genes compared to P. indica-colonized banana plants challenge inoculated with BBrMV. P. indica also inhibited the expression of the viral genes (P3 and HC-Pro) involved in symptom development. P. indica-colonized banana plants reduced the BBrMV symptoms severity by enhancing chlorophyll biosynthesis; and decreasing chlorophyll degradation and carotenoid biosynthesis and degradation; and inhibiting the viral genes responsible for symptom development in addition to enhanced growth and yield of banana plants. [ABSTRACT FROM AUTHOR]

The ability to endure extreme corrosion in challenging environments is reduced in stainless steel. This can be addressed by appropriate surface modification techniques to redefine the surface with the required properties. The characteristics of the atmospheric plasma sprayed AlCoCrFeNi High Entropy Alloy (HEA) on SS316l are presented in this study. The coating characterisation revealed uniform coating with homogeneous deposition of gas-atomized AlCoCrFeNi HEA spanning for 150 µm. The coated substrates were further annealed for 2 h at 400 °C, 550 °C, 700 °C and 850 °C and the annealing at 550 °C offered enhanced microstructure. Annealing the coated sample at 550 °C offered a 46% improvement in microhardness against the uncoated sample post-annealing. The electrochemical corrosion tests showcased improved corrosion resistance after annealing through the formation of a protective oxide layer and the influence of HEA. Hot corrosion tests at 900 °C resulted in 10.1%, 8.49%, and 10.36% improved corrosion resistance for the coated sample annealed at 550 °C than the coated sample pre annealing and 44.09%, 44.25%, and 42.09% than the uncoated sample pre annealing under three salt mixtures respectively. The microstructural analysis examines various corrosion modes and verifies the presence and formation of protective oxide layers. [ABSTRACT FROM AUTHOR]

Magnesium alloys are well known for their light weight and low density, which facilitates their utilization in a wide range of engineering applications. When softer magnesium alloys are reinforced with hard ceramic particles, the machinability of magnesium alloys is expected to improve. In the current work, limestone powder (LSP) was used as a bioceramic reinforcement in AZ31 magnesium alloy, and the composites were fabricated through gravity stir casting technique. LSP particles were characterized by x-ray diffraction (XRD). Magnesium composite specimens were initially subjected to tensile tests to identify the best composite configuration. Composites with 6% LSP possessed high tensile strength and only these composites were subjected to drilling analysis. Generalized regression neural network (GRNN) has been used to forecast the surface roughness of AZ31 magnesium alloy composites during drilling. Outputs of drilling operations were utilized to train the neural network model and the values predicted by the GRNN technique were ascertained using confirmation experiments. It was concluded that bioceramics improved the machinability of the magnesium alloy composites and the GRNN application towards prediction of surface roughness showed satisfactory results exhibiting less deviation from the experimental results even for any value considered within the limits of the parametric levels. [ABSTRACT FROM AUTHOR]

Functionally graded A333/6wt.%B4C/4wt.%ZrO2 hybrid composite manufactured through horizontal-centrifuge casting is subjected to statistical investigation focused on the parametric influences and interactions on wear responses–specific wear rate and coefficient of friction. Taguchi's L27 orthogonal array design facilitates accurate trend analysis of factors against responses. Mathematical model development using Response Surface Methodology optimizes the wear responses, identifying the most efficient parametric combinations using Analysis of Variance and Signal to Noise ratios. Applied load (10, 30, 50 N), sliding distance (500, 1000, 1500 m) and counter plate hardness (210, 260, 300 HV) are compared to identify the influential hierarchy of factors during pin on plate reciprocating wear tests. The lowest specific wear rate is identified at a combination of 10 N, 500 m, 210 VHN. Whereas, the optimum COF is identified at a combination of 10 N, 500 m, 260 VHN. Quadratic model predicts the wear responses and confirm the closeness (5.2% variance) of predicted values against actual values. The model terms (Load, Distance, Counter plate hardness) of ANOVA with 'P-value' less than 0.05 are identified as significant terms. Superior micro-hardness (178.9 ± 1.6 HV) and tensile strength (248.3 ± 2.7 MPa) are observed at the outermost layer (18 mm), which are 35 and 14% higher than the innermost layer (2 mm). Worn surface analysis on the composite specimens identify their corresponding wear mechanisms and counter plate analysis confirm the formation of unstable tribolayer that regulate wear trend. [ABSTRACT FROM AUTHOR]

The advancement of the wire arc additive manufacturing (WAAM) process has been significant due to the cost-effectiveness in producing large metal components with high deposition rates. With the growth in the understanding of WAAM, researchers have found that the microstructure and mechanical properties of the fabricated components are greatly improved. As a result, a diverse range of materials have been linked to the process, leading to a wider application of WAAM in various industries. Thus, this review paper provides a comprehensive analysis of the recent advancements in WAAM, a technology that combines arc welding with additive manufacturing. The focus is on the microstructure, mechanical properties, materials used, process-related defects, and post-process treatments. The paper aims to offer guidance on producing high-quality and defect-free components by aligning the material characteristics with the capabilities of various WAAM techniques. The results of the paper highlight the strengths and limitations of WAAM and provide insights into its future prospects. This information is valuable for academics, designers, and manufacturers in the field, serving as a milestone for future WAAM research and application. [ABSTRACT FROM AUTHOR]

Thermal spraying is a broad terminology for a coating process in which materials are deposited in a spray of finely distributed liquefied or semi-liquefied particulates to build layered deposition coatings. Duplex and composite coatings can be utilized in the thermal spray technique to enhance the tribological properties of a broad range of engineering materials while saving money; service life extension, maintenance expenses, and replacement costs are lower than for single-layered coatings. As a result, this paper critically analyses various pre-processing surface treatments for substrates, commonly used thermal spray processing methods, and various post-processing surface treatments for thermally sprayed substrate materials. This paper also includes a description of several characterization methodologies as well as some comprehensive prospective applications for engineering components with challenges and scopes. Thus, this paper provides a fundamental understanding of surface treatments to researchers who use thermal spray coating techniques. [ABSTRACT FROM AUTHOR]

Polymer matrix composites have always piqued the curiosity of the scientific, technological communities and are being recognized as the best option for a wide range of engineering applications owing to their superior mechanical qualities, namely stiffness and high specific strength. In addition, these materials offer useful design flexibility and comparatively better fatigue and corrosion resistance than many other materials. These are thus recognized as advanced composite materials due to their superior mechanical properties and comparative ease of fabrication. As a result, manufacturers have turned towards these advanced composites for a wide range of applications in a variety of industries. A manufacturer or designer must choose appropriate constituents of a composite for a particular application while considering all the composite's properties. This stands as one of the main objectives of this review, i.e. to explore various matrices and reinforcement combinations used for different applications taking their properties into accord. This extensive analysis includes a detailed review of certain selective fabrication techniques. In addition to that, polymer matrix composites' numerous applications in today's environment are also discussed, as well as the challenges that they pose in diverse contexts. Through this review, researchers will achieve a better understanding of the significance of these materials and their adaptability in various applications. [ABSTRACT FROM AUTHOR]

This study investigates the reciprocating wear behaviour of heat-treated ZrO2 reinforced Al7Si0.3Mg functionally graded composite under unlubricated conditions by varying the heat treatment conditions and applied load using Taguchi's Design of Experiment methodology. The independent parameters chosen were ageing temperature (145, 165, 185 °C), ageing time (8, 10, 12 h), and applied load (20, 40, 60 N), whereas specific wear rate was the response parameter, as determined through Taguchi's L27 Orthogonal Array. Wear performance was assessed using a pin-on-flat plate linear reciprocating tribometer. Statistical analysis and the percentage contribution of each process variable to the wear rate characteristics and their importance to the tribological behaviour was defined through ANOVA. Optimum wear rate was obtained at a parametric combination of 20 N load, 165 °C ageing temperature, and 10 h ageing time. The confirmation studies revealed an error percentage of 6 ± 2.5% for heat-treated composite when comparing the performance measures derived by optimal parameter values with experimental data. Analysis revealed that ageing temperature was the most influential factor, followed by applied load and ageing time. Atomic force microscopy and worn morphology analysis on the heat-treated composite revealed severe wear at extreme ageing and applied loads, and mild wear at optimum loading conditions. These composites are best suitable for pump parts and automotive piston-cylinder arrangements which involve reciprocating motion. [ABSTRACT FROM AUTHOR]

This review paper aims to look at silicon-based ceramic matrix composites and infiltration-based approaches for them. There are many different types of infiltration-based manufacturing processes, each with its own set of features. The best technique is chosen depending on the needs and desired attributes. With these considerations in mind, any type of infiltration might be selected to meet the requirements. Silicon-based ceramics has been highly used in the fields of aerospace, medical, automobile, electronics, and other various industries so it is important to study about their applications as well. This review outlines the evolution of composites from early 7000 BCE to composites today and discussed about various infiltration techniques for manufacturing silicon based ceramic matrix composites. This article also gives the comprehensive review of general characteristics and mechanical properties of silicon-based composites used in a variety of engineering sectors. The application section entails the wide range of engineering fields with consideration of infiltration techniques, which would be helpful for researchers to study and correlate the different infiltration techniques for end applications. [ABSTRACT FROM AUTHOR]

This research compares the reciprocating tribo-mechanical behaviour of functionally graded A333 (Al-9Si-3Cu) alloy, Al-9Si-3Cu/6wt%B4C mono-composite and Al-9Si-3Cu/6wt%B4C/4wt%TiB2 hybrid-composite. Cylindrical test samples of both alloy and composites were horizontal centrifuge cast. Metallography of alloy revealed grain refinement and throughout presence of B4C particles along the cross-section of both functionally graded composites. Whereas, a rising gradient of TiB2 particles were observed towards the outer zone of hybrid composite. Comparative analysis on micro-hardness and tensile strength, revealed an improvement of 37.4% and 17.6% respectively for outer hybrid-composite; 22.6%, and 12.2% respectively for outer mono-composite with respect to alloy. Reciprocating wear analysis confirmed superior anti-wearing at outer hybrid-composite. Worn morphological analysis confirmed predominant delamination wear mechanism for outer zones of alloy, mono and hybrid composites. Abrasive, adhesive and delamination wear in combination, led to oxide layer formation at intermediate sliding distances. Hybrid composite is functionally graded and developed for automotive engine component applications. [ABSTRACT FROM AUTHOR]

This study investigates the effect of Strontium (Sr) grain modifier addition on Al-9Si alloy and B4C reinforced composite fabricated by two step gravity casting technique. The optimum level of Sr was identified as 0.08 wt.% for complete modification. The modified cast components were thermally treated by T6 temper to enhance the tribo-mechanical properties. Metallographic observation revealed the transformation of acicular Si grains to fine fibrous in as-cast condition, which later transformed to spheroidised eutectic Si after heat treatment. The combined effect of grain modification by Sr and the influence of spheroidised eutectic Si enhanced the mechanical properties. Heat treated modified composite exhibited superior tribological properties when compared to other components under varying applied normal loads and sliding distances. Worn mechanism of heat treated modified composite was observed to be minor delamination wear regime at high load (55 N) and sliding distance (1500 m). [ABSTRACT FROM AUTHOR]

Functionally graded (FG) Al8Si3Cu alloy and 8 wt% titanium carbide (TiC) reinforced composite (∅out100 × ∅56in × 100 mm) was fabricated through horizontal centrifugal casting, followed by T6 heat treatment. Metallographic analysis confirmed fine grain structure at FG alloy outer layers, whereas heat-treated alloy displayed spheroidised eutectic silicon. Gradient microstructure was observed for FG composite. Enhanced hardness for outer layer (10.31%) and tensile strength for outer zone (58.71%) were observed for heat-treated Al8Si3Cu/TiC composite owing to the high concentration of spheroidised eutectic Si and TiC particles, compared to as-cast composite. Linear reciprocating wear analysis performed on as-cast, heat-treated alloy and composite, respectively, at varying load (10–40 N) and sliding distance (500–2000 m) confirmed increasing wear rate, with heat-treated composite having superior wear resistance. Delamination wear was the predominant wear mechanism influencing wear behaviour of heat-treated composite. The alloy and composite were characterized using X-ray diffraction (XRD), energy dispersive spectrometry (EDS), optical microscopy (OM) and scanning electron microscopy (SEM). [ABSTRACT FROM AUTHOR]

This study investigates the tribo-mechanical behaviour of as-cast and heat treated A359/ 6 wt.% Ti-based particulate reinforced homogeneous composites (TiB2, TiO2, and TiC) processed through modified stir casting technique. Metallographical observation on as-cast homogeneous composites revealed a uniform distribution of reinforcements throughout the cross-section. In heat treated composites, the tribo-mechanical properties were enhanced by the formation of spheroidized alpha eutectic Si. TiB2 and TiO2 exhibited superior interfacial bonding with Al-matrix, whereas TiC showed marginal wetting. Linear reciprocating wear experiments were performed on all as-cast and heat treated components by varying loads (15–55 N) and sliding distances (500–2500 m). Results revealed superior hardness (182.5 HV), tensile strength (271.6 MPa) and wear resistance for heat treated A359/TiB2 composite than TiO2 and TiC reinforced composites. The wear rate and coefficient of friction was observed to be dependent on the applied load and type of reinforcement particle in the composites. Worn surfaces of composites exhibited severe delamination wear mechanism. [ABSTRACT FROM AUTHOR]

The current study focuses on improving the mechanical and reciprocating wear characteristics of centrifugally cast functionally graded A356(Al-7Si-0.3 Mg)/10 wt.% B4C composite through T6 heat-treatment. Comparative analysis was performed between as-cast and heat-treated composite. Metallographic analysis confirmed the presence of reinforcement particles alongside grain boundaries and spheroidised eutectic silicon particles in heat-treated composite. Outer layer of heat-treated composite displayed superior hardness (24.09%), ultimate tensile strength (44.8%) and tribological properties when compared to outer layer of as-cast composite. With increasing applied load (15, 25, 35 N), wear rate and co-efficient of friction increased whereas wear rate and co-efficient of friction decreased as sliding distance (500, 1000, 1500 m) increased. Worn morphologies confirmed extreme delamination wear and particle pull-out at high applied loads whereas traces of oxide formations were observed at high sliding distance. Heat-treated composites have superior characteristics due to the presence of spheroidised eutectic silicon particles and precipitate formation, which makes it an alternative material for reciprocating applications in aerospace and automotive industry. [ABSTRACT FROM AUTHOR]

The present study focused on strontium (Sr)-induced A383 alloy and composite reinforced with 6 wt% boron carbide (B4C) particles processed by stir casting technique. From metallographic analysis, it was confirmed that Sr addition modified needle structures of α-Si to fine α-Si. This grain refinement enhanced the hardness of A383-Sr alloy by 52.72% and A383-Sr/B4C by 73.6%, and tensile strength of A383-Sr by 69.93% and A383-Sr/B4C by 81% when compared to A383 unmodified alloy. Fractography analysis proved that both Sr-induced alloy and composite had brittle failure with clear formation of flakes and cleavages. Reciprocating wear test was conducted at various loads (15 N, 25 N, 35 N) and at sliding distances (500 m, 1000 m, 1500 m). It was observed that wear rate was proportional to the applied load. Wear rate increased with increase in sliding distance, but after 1000 m, there was decline in wear rate. Worn surface analysis revealed the presence of oxide layer after 1000 m which enhanced wear resistance. A383-Sr/B4C composite possessed superior wear resistance compared to other. [ABSTRACT FROM AUTHOR]

The key objective of the paper is to investigate the mechanical and wear Properties of functionally graded copper composite (Cu–11Ni–4Si) reinforced with 10 wt% graphite synthesised using stir casting followed by horizontal centrifugal casting technique. Microstructural analysis conducted radially from outer surface exhibited an increasing gradient of particle distribution and maximum hardness of 195 HV was observed at inner surface. Tensile strength of outer and (1–8 mm) and inner zone (9–15 mm) was determined and failure mechanism was analysed. Mechanical tests revealed better properties at inner surface and wear resistance of this layer was analysed using pin-on-disc tribometer based on Taguchi's L27 orthogonal array with three process parameters, applied loads (10, 20 and 30 N), sliding velocities (1, 2 and 3 m s−1) and sliding distances (500, 1000 and 1500 m). Optimum parameters were identified and confirmation of experiments was carried out. Worn surface was analysed using Scanning Electron Micrograph and oxide layer formation was noticed at increased velocities which enhanced wear resistance. [ABSTRACT FROM AUTHOR]

This research investigates the effect of heat treatment on mechanical and tribological properties of Cu–11Ni–4Si—10 wt% B4C functionally gradient composite, which is fabricated by the centrifugal casting method. The cast specimens are solutionized at 700 °C for 90 min, followed by air quenching/water quenching. The specimens are artificially aged at different temperatures (500 °C, 550 °C, and 600 °C) and time (1 h, 2 h, and 3 h). The optimum heat treatment condition is established based on the microstructure, microhardness, and tensile strength. The specimens that are heat-treated at optimum condition are subjected to tribological tests by varying the load between 15.8 and 44.44 N and sliding velocity between 0.8 to 2.2 m/s for a sliding distance of 1000 m and 1500 m. The surface morphology and topography of the worn surface are analyzed using FESEM and AFM, respectively. The influence of load and sliding velocity on the wear rate of the specimens is explored using the mathematical models, which are developed using a hybrid polynomial–radial basis function. The results indicate that the load has a direct influence on the wear rate, while the wear rate follows crest parabolic pattern with an increase in the sliding velocity. [ABSTRACT FROM AUTHOR]

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The research aims to fabricate LM25 alloy and composites reinforced with 15 wt% TiB2, 15 wt% ZrO2 and 15 wt% WC using squeeze casting technique. The fabricated cylindrical castings were of dimensions 50 mm diameter and 150 mm length. Microstructural analysis revealed better distribution of reinforcement particles for each composite, which provided better hardness and tensile properties. Physical and wear properties were studied comparatively to understand the influence of reinforcements, and tungsten carbide (WC)-reinforced composites showed better performance. Fractographic analysis revealed ductile mode of failure for LM25 and a combination of ductile and brittle mode for its composites. Dry sliding performance of both alloy and composites was analysed under different sliding conditions of applied load (10–50 N), slide distance (500–2500 m) and slide velocity (1–5 m/s) using pin-on-disc tribometer. WC-reinforced composite improved resistance to wear by 70% compared to alloy. Wear analysis of composite using scanning electron microscope showed change in wear features from mild to severe at high loads. The developed LM25/WC composite was found to be most suitable for non-lubricated slide applications. [ABSTRACT FROM AUTHOR]

The current study aims to synthesize copper alloy and functionally graded Cu-10Sn-5Ni/10Si3N4 composite using horizontal centrifugal casting method and compare their mechanical and adhesive wear characteristics. The fabricated castings have dimensions of Øout100 x Øin70 × 100 mm. Microstructural analysis revealed that inner region of composite possesses higher concentration of reinforcement particles, resulting in better hardness and tensile properties at this region compared to outer regions of both unreinforced alloy and composite. Analysis of dry sliding wear performance and frictional coefficient was performed at inner region of the composite under different sliding conditions using Taguchi's method on pin-on-disc tribometer. Signal-to-Noise ratio and Analysis of Variance results concluded that applied load had the most influence on wear rate and coefficient of friction followed by sliding distance and sliding velocity. Worn surface morphologies of composite specimens revealed a transition from mild to severe wear at high loads. The fabricated composites are well suitable for sliding tribological applications. [ABSTRACT FROM AUTHOR]

Cu-11Ni-4Si/10wt.% Si3N4 functionally graded composite of dimension Øout 100 mm × Øin 70 mm × 100 mm was fabricated via centrifugal casting and the mechanical and three body abrasive wear behavior were studied. Microstructural analysis along the radial direction revealed high concentration of Si3N4 particles at the inner periphery of the composite, and XRD analysis confirmed the presence of introduced reinforcement. Highest micro-hardness (207 HV) was observed at the inner periphery of composite having highest concentration (53 vol.%) of reinforcement particles and the inner zone displayed higher tensile strength (425.58 MPa). Abrasive wear test based on L27 orthogonal array, was performed only at inner periphery based on the mechanical behavior. Signal-to-Noise ratio and Analysis of Variance were performed to analyze the influence of parameters such as load, speed and time on wear rate. Results showed that applied load had the highest influence (60.45%) on wear rate followed by speed and time. Scanning electron microscopy analysis was carried out on worn samples and was observed that wear changed from mild to severe as parameters were increased. This composite is suited for automotive applications where the improved abrasive wear characteristics can be utilized to a greater effect. [ABSTRACT FROM AUTHOR]

LM13/12wt.%Si3N43wt.%Gr hybrid composite was fabricated by liquid metallurgy route and its tribological characteristics were tested using pin-on-disc tribometer. The experiments were conducted as per L27 orthogonal array to study the influence of process parameter at normal and elevated temperature (150 °C) by varying process parameters such as load (10, 20, 30 N), sliding velocity (1, 2, 3 m/s) and sliding distance (750, 1250, 1750 m). The results revealed that the wear rate at both temperatures was proportional to load due to the stress induced which fractures Si3N4 particles and stripes aluminium matrix. As the sliding velocity increases, wear rate showed an increasing trend due to three body abrasion from eroded Si3N4 grits. The wear rate was inversely proportional to sliding distance, because of MML (Mechanically mixed layer) formed from chemical reactions between tribo-layers. When load increases COF (Coefficient of friction) decreases then increases due to lubricating and tillage effect. As velocity and distance increases, COF decreases due to thermal softening, hardening of layer and also the lubrication effect produced by chemical reactions. Analysis of variance (ANOVA) and S/N ratio at room temperature and elevated temperature for both Wear rate and COF were developed to study the most significant parameters on corresponding responses. Confirmation experiments were conducted to validate multi-linear regression model. Worn surfaces were examined using scanning electron microscope (SEM) to investigate wear characteristics. Energy dispersive X-ray spectroscopy (EDAX) and X-ray diffraction (XRD) results confirmed the formation of MML and different phases formed during wear mechanism. The developed material can be used to fabricate cylinder liners, cylinder blocks and brake rotors. [ABSTRACT FROM AUTHOR]

Centrifugally cast functionally graded Cu-11Ni-4Si/10 wt% TiC composite of dimension Øout100 × Øin70 × 100 mm was heat treated to enhance the mechanical and tribological characteristics. Samples from inner zone (9-15 mm) were initially solution treated (850 °C/1 h), water quenched, and aged at varying temperatures (450, 500, and 550 °C) and ageing time (4, 6 and 8 h). The highest hardness (192 HV) displayed by the specimen aged at 550 °C/6 h was chosen for dry sliding tribological studies performed at varying applied loads (10-30 N), sliding velocities (1-3 m/s) and sliding distances (500-1500 m). An improvement of 65% was observed on comparing the micro-hardness values of heat-treated and non-heat-treated composites, while a decrease of 54.8% was observed on comparing the wear rate of heat-treated alloy and composite at optimum parameters. The wear rate increased with applied load, decreased initially and then increased with sliding distance and sliding velocity. Analysis of variance predicted applied load as the major influential parameter, followed by sliding distance and sliding velocity. Worn surface analysis revealed increase in delamination along with mild to severe wear transition with increase in applied load, and the formation of a mechanically mixed layer with increase in sliding velocity. This composite having high wear rate and hardness could be utilized for automotive load bearings, cylinder liners and brake drum applications. [ABSTRACT FROM AUTHOR]

The objective is to fabricate Cu-10Sn alloy and its composites reinforced with varying wt% of SiC (5, 10 and 15) to investigate its dry sliding wear behaviour. Microstructural analysis for composites revealed well dispersed SiC particles within matrix except for 15 wt% SiC composite, where agglomeration took place. Amongst all composites and alloy, 10 wt% of SiC composite had better hardness (144 HV). The tribological analysis using Pin-on-Disc tribometer for all alloy and composites revealed increase in wear rate with increase in load and distance for all combinations of parameters (load, sliding distance, and sliding velocity). Worn surface analysis concluded that the wear rate decreased with increase in velocity for both 5 and 10 wt% SiC composite due to formation of Mechanically Mixed Layer. The composite with 10 wt% SiC showed enhanced wear resistance and hence can be used for tribological applications like bearings and bushes. [ABSTRACT FROM AUTHOR]

Al 6060 alloy was coated with TiO2 by spray pyrolysis technique at 400 °C using Titanium isopropoxide as precursor. The adhesion of the coating with the alloy was enhanced by annealing at 450 °C for 1 h which increased the hardness by 50%. Dry sliding wear resistance was experimented based on Taguchi’s L27 array using pin-on-disc tribometer by varying parameters such as applied load (15, 25 and 35 N), sliding distance (500, 1000 and 1500 m) and sliding velocity (1.5, 2.5 and 3.5 m/s). Analysis of Variance predicted the major influence by load, followed by velocity and distance. Trend depicted an increase in wear rate with load and distance, whereas with velocity it decreased initially and then increased. Optimum condition for maximum wear resistance was determined from the Signal-to-Noise ratio. Experimental results were validated using regression equation with an error less than 3%. Scanning Electron Microscope analysis of the worn surfaces had revealed more defoilage and lay-off as the applied load was increased. [ABSTRACT FROM AUTHOR]

The objective of this work is to fabricate functionally graded unreinforced copper alloy (Cu-10Sn) and a Cu-10Sn/SiC composite (Øout100 × Øin70 × 100 mm) by horizontal centrifugal casting process and to investigate its mechanical and tribological properties. The microstructure and hardness was analysed along the radial direction of the castings; tensile test was conducted at both inner and outer zones. Microstructural evaluation of composite indicated that the reinforcement particles formed a gradient structure across the radial direction and maximum reinforcement concentration was found at the inner periphery. Hence maximum hardness (205 HV) was observed at this surface. Tensile test results showed that, the tensile strength at inner zone of composite was observed to be higher (248 MPa) compared to that of the outer zone and unreinforced alloy. As mechanical properties showed better results at inner periphery, dry sliding wear experiments were carried out on the inner periphery of composite using pin-on-disc tribometer. Process parameters such as load (10-30 N), sliding distance (500-1500 m) and sliding velocity (1-3 m/s) were analyzed by Taguchi L27 orthogonal array. The influence of parameters on wear rate was analyzed by signal-to-noise ratio and analysis of variance. Analysis results revealed that load (54%) had the highest effect on wear rate followed by sliding distance (18.2%) and sliding velocity (3.7%). The wear rate of composite increased with load and sliding distance, but decreased with sliding velocity. Regression equation was developed and was validated by confirmatory experiment. Worn surface of composite was observed using scanning electron microscopy and transition of wear was observed at all extreme conditions. [ABSTRACT FROM AUTHOR]

This paper studies the dry sliding wear behavior of Al-Si6Cu/Ni coated SiC metal matrix composite fabricated using stir casting technique. The SiC reinforcement particles coated with Ni by electroless coating were incorporated at 10-wt% into the metal matrix. The wear behavior was studied on unlubricated pin-on-disc tribometer based on design of experiments modelled using Response Surface Methodology for various sliding parameters such as applied load, sliding velocity and sliding distance. The minimum wear rate condition and optimum condition of the parameters were detected from the developed model. The analysis of variance showed the influence of each parameter on wear rate. The confirmation experiments were done to ensure the validity of the developed regression model. The worn-out surface morphologies of the metal composite were studied using scanning electron microscope analysis. From the experimental results it was found that the parameter which influenced the wear behavior was applied load followed by sliding velocity and distance. The confirmatory experiments confirmed the RSM’s design as precise statistical model in developing regression results with less error. The surface plot of wear characteristics showed that irrespective of the conditions of sliding velocity and distance the wear rate increased on increasing the load. The wear rate exhibited a non linear relationship with sliding velocity and distance. The scanning electron microscopy revealed that higher material deformation was observed at higher load resulting in severe wear of the composite material. [ABSTRACT FROM AUTHOR]

Centrifugal casting was adopted for fabricating AlSi5Cu3/10 wt% SiC functionally graded metal matrix composite under three different centrifugal speeds of 800, 1000 and 1200 rpm, and hollow cylindrical components (φout 150 × φin 132 × 150 mm) were obtained. Microstructures of outer and inner periphery of all composites were observed through optical microscope and micro hardness of outer, intermediate and inner region of composite was tested using Vicker’s hardness tester. Results revealed that outer region of the composites centrifuged at all speeds have particle rich region with higher hardness. Abrasive wear experiments were conducted only on surface of particle rich region based on Taguchi’s technique by varying parameters such as centrifugal speed of casting process, rotating speed and applied load of abrasive wear tester. Analysis of variance results revealed that, centrifugal speed had highest significance on wear rate. Abraded surfaces were examined using scanning electron microscope and the maximum wear resistance was observed on particle rich zone of composite centrifuged at 1200 rpm. [ABSTRACT FROM AUTHOR]

In this paper, the abrasive wear behavior of Al LM 25/10 wt% TiC metal matrix composite has been studied experimentally. The composite specimens were fabricated using stir casting technique. Microstructural evaluation revealed uniform distribution of reinforcement particles throughout the matrix. Abrasive wear experiments were designed for different values of load, speed and time through response surface methodology and were performed using three body abrasion tester. Surface plots for wear rate against all combinations of parameters revealed that wear rate increased with increasing load and time, but decreased with increasing speed. The generated regression equation established proper relation between parameters and wear rate, confirming the accuracy of the developed model. The results of optimization of process parameters revealed that a minimum wear rate of 0.00104 mm/Nm was obtained at 27 N, 139 rpm and 3 min. Scanning electron microscope analysis results substantiated that wear rate was comparatively more at higher loads. [ABSTRACT FROM AUTHOR]

l-Cysteine capped zinc oxide (CCZ) nanoparticles (NPs) were synthesized by the chemical precipitation method. They were immobilized onto a biodegradable poly(3-hydroxybutyrate- co-3-hydroxyhexanoate) [P(3HB- co-3HHx)] by electrospinning. ZnO, CCZ and immobilized CCZ were spectrochemically characterized using X-ray diffraction, photoluminescence and Fourier transform infrared spectra. The surface morphology of the catalyst was studied by scanning electron microscopy technique. The as-synthesized material exhibited excellent photocatalytic activity for the degradation of rhodamine B (RhB) dye under both UV and visible light irradiation. The higher photocatalytic activity of the immobilized CCZ in the degradation of RhB was mostly attributed to their web structure with small size. It was found that the immobilized CCZ retained its photocatalytic activity up to three successive catalytic runs, which was found difficult with bare ZnO. Thus, the P(3HB- co-3HHx) support would be useful in immobilizing metal oxide NPs for diverse applications owing to its biodegradability and biocompatibility. [ABSTRACT FROM AUTHOR]

The main objective of this paper was to fabricate Cu10Sn5Ni alloy and its composites reinforced with various contents of SiN particles (5wt%, 10wt%, and 15wt%) and to investigate their dry sliding wear behavior using a pin-on-disk tribometer. Microstructural examinations of the specimens revealed a uniform dispersion of SiN particles in the copper matrix. Wear experiments were performed for all combinations of parameters, such as load (10, 20, and 30 N), sliding distance (500, 1000, and 1500 m), and sliding velocity (1, 2, and 3 m/s), for the alloy and the composites. The results revealed that wear rate increased with increasing load and increasing sliding distance, whereas the wear rate decreased and then increased with increasing sliding velocity. The primary wear mechanism encountered at low loads was mild adhesive wear, whereas that at high loads was severe delamination wear. An oxide layer was formed at low velocities, whereas a combination of shear and plastic deformation occurred at high velocities. The mechanism at short sliding distances was ploughing action of SiN particles, which act as protrusions; by contrast, at long sliding distances, direct metal-metal contact occurred. Among the investigated samples, the Cu/10wt% SiN composite exhibited the best wear resistance at a load of 10 N, a velocity of 2 m/s, and a sliding distance of 500 m. [ABSTRACT FROM AUTHOR]

The cysteine capped ZnO/graphene oxide (CCZG) composite was successfully synthesized by co-precipitation method. The as synthesized CCZG was characterized by X-ray diffraction, diffused reflectance spectra, scanning electron microscopy, transmission electron microscope, Fourier transform-infra red spectral studies. The photocatalytic result reveals that the CCZG composite exhibited enhanced photocatalytic activity towards degradation of Rhodamine B (RhB) under compact fluorescent lamp (CFL) light irradiation. It is found that increase the graphene oxide content in the composite increases the photocatalytic activity which is higher than bare CCZ. The improved photocatalytic activity reduces the recombination of photogenerated charges and high dye adsorption ability of the composites. Further the mineralization of RhB dye has been confirmed by TOC analysis. A mechanism was also proposed for the degradation of RhB by CCZG under CFL light. [ABSTRACT FROM AUTHOR]

Mechanical properties and abrasive wear behaviour of functionally graded Al-Si12Cu/AlO metal matrix composite fabricated under centrifugal casting technique was investigated and compared with unreinforced aluminium alloy. Hollow cylindrical component with dimensions 150 × 150 × 16 mm was produced under the centrifuging speed of 1200 rpm by incorporating 10 wt% AlO particles of size 30-50 µm. The distribution of the AlO reinforcement particles at outer, middle and inner surfaces in matrix was examined through the microstructural analysis. Hardness and tensile strength of the aluminium alloy and functionally graded composite were tested through microhardness tester and universal testing machine respectively. Abrasive wear of aluminium alloy and functionally graded composite was tested through dry abrasion tester for various loads and speeds on outer, middle and inner surfaces of composite specimens. Scanning electron microscopy analysis was carried out on the fractured tensile specimens and worn out specimens. The results revealed that particles were segregated more on the outer periphery and less on the inner periphery. The mechanical properties and the abrasive wear resistance of the functionally graded material were found higher than the unreinforced alloy. The wear rate was found to increase with increase in load, speed and for the distance from the outer periphery of the casting. The worn out surfaces revealed more cutting and ploughing as a result of three body abrasion wear caused by silica sand particles. [ABSTRACT FROM AUTHOR]

Both inhibitory and activating forms of natural killer (NK) cell receptors are found in mammals. The activating receptors play a direct role in the recognition of virally infected or transformed cells and transduce activating signals into the cell by partnering with an adaptor protein, which contains a cytoplasmic activation motif. Activating NK receptors encoded by the mammalian leukocyte receptor complex (e.g., killer cell immunoglobulin-like receptors) and the natural killer complex (e.g., Ly49s) partner with the adaptor protein DAP12, whereas NK receptors encoded in the CD94/NKG2 complex partner with the adaptor protein DAP10. Novel immune-type receptors (NITRs) found in bony fish share several common features with immunoglobulin-type NK receptors. Nitr9 is a putative activating receptor in zebrafish that induces cytotoxicity within the context of human NK cells. One isoform of Nitr9, Nitr9L, is shown here to preferentially partner with a zebrafish ortholog of Dap12. Cross-linking the Nitr9L–Dap12 complex results in activation of the phosphytidylinositol 3-kinase→AKT→extracellular signal-regulated kinase pathway suggesting that the DAP12-based activating pathway is conserved between bony fish and mammals. [ABSTRACT FROM AUTHOR]

Symptoms of excessive shoot proliferation were observed in the Njallani cultivar of small cardamom accompanied by stunting of stalks with fewer degenerated capsules at Nedumkandam Panchayat of Idukki district of Kerala in 2017. Five symptomatic Elettaria cardamomum shoot proliferation (ECSP) plant samples were collected and processed for DNA extraction and PCR assays utilizing universal phytoplasma 16S ribosomal-specific primers pair, P1/P7 followed by R16F2n/R16R2. Sequence comparison analysis of the R16F2n/R16R2 region of 16SrRNA gene showed 100% sequence identity with the 'Candidatus Phytoplasma australasia'- related strain. Phylogeny and virtual RFLP analyses of 16S rRNA gene sequences confirmed the association of 'Ca. P. australasia' strain subgroup D with ECSP disease. The association of 16SrII group was further established and validated by amplifying phytoplasma-specific multilocus candidate genes by utilizing specific primers of secA, secY, SAP11, and tuf genes. The multilocus gene sequence comparison analysis again confirmed the association of 'Ca. P. australasia' with the ECSP phytoplasma isolate. This is the first report of phytoplasma association with small cardamom. [ABSTRACT FROM AUTHOR]

We report in this the development of nanocomposite rutin-reduced graphene oxide/titanium oxide (R-rGO/TiO2) through a chemical precipitation method to enhance the electrochemical detection and photocatalytic efficiency of the 2,4-dichlorophenol (DCP). The structural and morphological characterization of the as-fabricated nanocomposites were carried out by X-ray diffraction, Fourier transforms infrared spectroscopy (FT-IR), scanning electron microscopy, transmission electron microscopy, etc. The R-rGO/TiO2 electrochemical sensor was developed for 2,4-dichlorophenol (DCP) and rutin oxidation based on composite altered glassy carbon electrode (GCE). Moreover, R-rGO/TiO2/GCE composite exhibited accomplished electrocatalytic activity towards DCP in the linear range 5–150 μM and a low detection limit of 0.02 μM (S/N = 3). The TiO2 nanomaterial was well embellished on the surface of the graphene sheets, which helps in electron transfer from TiO2 to graphene and hence interruption by recombination method, to the foremost R-rGO/TiO2/GCE enhance the photocatalytic activity. The electrochemically sensed pesticide intermediate 2,4-DCP was the photo-catalytically degraded by the same R-rGO/TiO2 nanocomposite for water remediation. The nanocomposite exhibits higher degradation efficiency on 2,4-DCP when compared with the individual materials. After the degradation, the degraded water was studied for the animal survival study using Artemia salina as the model eco-toxicology model. [ABSTRACT FROM AUTHOR]