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In this study, Glow Discharge Plasma Nitriding (GD_PN) of C-300 maraging steel is conducted at 425 °C to 500 °C for 4 h using $$\text{H}_{2}$$ and $$\text{N}_{2}$$ in a ratio of 4:1. The GD_PN treated surface is characterized by XRD and SEM and assessed for micro-hardness, tensile strength, corrosion as well as wear resistance. The micro-hardness measurements show an improvement in the hardness of the samples’ surface by an approximate factor of 3.2. In the context of the case depth, it varies from 11.53 μm for 425 °C to 92.58 μm for 500 °C. The wear test results show improvement in wear resistance by a factor of 23.46 for treatment at 490 °C compared to the untreated sample. The tensile tests indicate that the ultimate tensile strength increases by a factor of 2.23 for treatment at 490 °C in comparison with the untreated sample. The XRD results depict that the plasma nitrided layer is incorporated with $${\gamma }^{^{\prime}}-\text{Fe}_{4}\text{N}$$ as well as $$\varepsilon -\text{Fe}_{2-3}\text{N}$$ phase. Finally, best corrosion resistance is observed for maraging steel sample treated at 490 °C.

Tailor welded blank sheets made of friction stir welding (FSW) process have found many applications in aerospace, automobile, marine, and other industries. In the present study, two different aluminum alloys AA5083-O and AA6082-T6 having 2 mm thickness were used. This research presents the multi-responses optimization of process parameters, i.e., rotation speed (R), travel speed (T), and shoulder diameter (S) in the FSW process using response surface methodology (RSM) based on gray relational analysis (GRA) coupled with principal component analysis (PCA) technique. For the optimization of the process, the face-centered central composite design technique with minimal design was used to get the optimum level of the parameter. The objective of this paper is to find out the optimum level of the process parameters which yields the maximum responses, i.e., ultimate tensile strength, total elongation, yield strength, dome height, and microhardness value. ANOVA technique was used to ensure the significant contribution of the individual and the combination of process parameters. The confirmatory run analyzed the optimized process parameters, and the experimental result was observed within 2.6% of error agreement with predicted values. GRA determined the optimum value of the input parameter with the PCA technique, a hybrid approach. The optimum value of R, T, and S was found at 1900 rpm, 40 mm/min, 12 mm, respectively. The microstructural study of variation in grain structure across the different zones of the FSW region was examined and tested by scanning electron microscope. The microhardness and formability tests for the optimized parameters were carried out. This research reveals that the multi-response optimization problem can be easily solved through RSM based GRA-PCA approach.

There are various types of reinforcements used in the development of aluminium based metal matrix composites. It was observed that by the use of ceramic particles, mechanical characteristics such as hardness and tensile strength were enhanced. However, density and cost was also increased. Groundnut shell is waste product that produces lots of soil pollution. By utilizing ground nut shell ash as reinforcement material with aluminium, mechanical properties can be improved. Further, density and cost of composite can be reduced. The aim of this review article is to study the influence of various types of reinforcements in the fabrication of composites with enhanced mechanical properties.

Matrix Composites (MMCs) and Metal Matrix Hybrid Composites (MMHCs) have transpired as leading materials. Keeping in view, the high specific strength and stiffness, superior wear and seizure resistance that these MMCs possess, they find application in automotive, aircraft and other engineering industries. The traditional reinforcement materials in Aluminium alloy improve the mechanical and wear properties but a high cost of creation is linked with them. Thus, agro wastes are a great alternative that can be contemplated for utilizing as the reinforcement. In this present work, the investigation of mechanical characteristics of biomass fly ash reinforced aluminium metal matrix composite has been performed. Biomass fly ash with different proportion (1%, 3%, 5%, and 7%) has been reinforced in the Aluminium alloy. Composites were synthesised via stir casting method. metallography, hardness, tensile and fracture toughness tests have been conducted to get a closer look on the properties of resulting composites. The results showed that an increase in the biomass fly ash content in the melted leads results in an increase in the, microhardness but decrease in tensile strength and impact strength.

Humanity depends (directly or indirectly) exclusively on agriculture for their survival. Due to the exponential growth in population, it is imperative to use new scientific tools and technologies such as nanotechnology in agriculture. The objective of this review is to provide an overview of the use of nanomaterials (NMs) and nanoparticles (NPs) in form of nanofertilizers (NFs) to enhance plant nourishment, reflecting their potential benefits and possible uses, and also assessing their potential impact on ecosystem. NFs possess an alternative approach as compared to biofertilizers, biopesticides and organic fertilizers that started from green revolution. NFs affect crop’s nutritional quality and stress tolerance in plants. There are both pons and cons of NPs and NMs when used in agriculture. These studies are necessary because NPs and NMs can be transferred to ecosystems by various pathways where they can cause toxicity to organisms, affecting the biodiversity and abundance of such ecosystems, and may ultimately even be transferred to consumers. The progress in the crop improvement processes such as implementation of nanodevices for genetic manipulation of plants depends on advanced techniques used in nanotechnology.

The present research work focused on Al 6061-Bagasse ash metal matrix composites are produced with stir casting process. The different mass fractions of bagasse ash particles (1, 3, 5 and 7%) under speed of 300 r/min. different mechanical properties such as hardness, tensile strength and toughness of fabricated aluminium metal matrix composites are tested. It was found that the mechanical properties were greatly affected with increasing percentage volume of reinforcement. The optical microscopy results affirmed the uniform conveyance of reinforced particles in the metal matrix combination.

In the present investigation, hybrid aluminium based composite material was developed by using two dissimilar aluminium alloys with Al2O3 and RHA reinforcement particles via Friction Stir Process. ...

In the traditional development of aluminum based composite materials ceramic particles such as SiC, Al2O3 and B4C etc. are customarily used as a reinforcement material for the aluminum matrix. Further, industries producing these ceramic particles emit huge amount of greenhouse gases which in turn cause a great amount of environment pollution. Moreover, the production of these ceramic particles is costly. Agro waste groundnut shell ash (GSA) is an agricultural waste product that produces soil and air pollution. In addition, its disposal is costly. In this study, an attempt was made to utilize agro waste GSA as a partial replacement for ceramic particles in the development of AA2024 aluminum based composite. Microstructure results showed a uniform distribution of GSA particles in the aluminum base metal matrix alloy. Maximum tensile strength and hardness were found to be 198 MPa and 64 BHN for 3.75 wt.-% reinforcement of GSA particles in the AA2024 aluminum base matrix material. Porosity and thermal expansion were found to be 12.96 % and 125 mm3, respectively for the AA2024/3.75 wt.-% GSA composite. Density, corrosion loss and the cost of the GSA reinforced composite continuously decreased by increasing the percentage of reinforcement. Specific strength and corrosion loss of the AA2024/3.75 wt.-% GSA green metal matrix composite were also found satisfactory.

Purpose This paper aims to produce hybrid reinforcement for the development of aluminium matrix composites using ball-billing technique to avoid or reduce the problem of agglomeration of the reinforcement during casting. Design/methodology/approach In the present investigation, a mixture of silicon carbide (SiC) and rice husk ash (RHA) powder in equal weight percentage ratio 4:4 (1:1) was alloyed mechanically in a ball-mill at distinct milling times of 15, 30, 45, 60 and 75 h. Morphological Characterization and density measurements of the ball-milled powder were carried out after different intervals of milling times. Findings The results revealed that the process of ball milling is a novel technique for the conversion of two or more powders in to an integer powder and reduces the problem of agglomeration also. The density measurement results revealed that an increasing trend of density initially and reduction of the density with the increase of milling time. The density value of the combined particles became comparable to the density of aluminium at the milling time of 75 h for the equal weight percentage ratio 4:4 (1:1) of SiC and RHA. Originality/value The manuscript highlights the research work related to the development of the reinforcement for the aluminium hybrid composites by ball milling process. The use of this process for the development of the reinforcement not only reduces the problem of the agglomeration but reduces the density mismatch of the reinforcement and matrix material also.

Porous carbon materials (PCM) hold great promise for multifarious applications (like energy conversion and storage devices, biological applications, photo-catalysis etc.) owing to their outstanding properties such as high surface area, accessible active sites, mass transport, diffusion etc. Interestingly, they appear as futuristic substitutes to replace the conventional and economically unviable Pt-based electrocatalysts for the oxygen reduction reaction in Fuel cells. PCM synthesized using biomass-derived sources have some clear advantages, vis-a-vis. their abundance in nature, characteristic sustainability, economic viability and environmental friendliness. Also, no harsh chemicals are being used for their synthesis, and they inherently contain variety of heteroatoms (N, P, S etc.) vital for the electrocatalytic activity. This review article will help researchers gain an in-depth understanding of bio-waste sources and composition; synthesis methods and their dependence on various parameters; templating methods and vital information like role of dopants and transition metals in influencing electrocatalytic activity, and will result in enabling biomass based PCM as electrocatalysts in future energy devices.

This paper explore the viability of novel microwave hybrid heating, Co-based coatings without CeO2 (unmodified) and with CeO2 (modified) in varying wt % (1, 2 and 3 wt %) were developed. The coatings were developed using domestic microwave oven of 2.45 GHz frequency, 900 W power and an irradiation time of 15 min. The characterization of unmodified and modified clads has been done in terms of microstructure, XRD, hardness and sliding wear behavior. The influence of sliding speed (1.2 and 2.4 m/s) and distance (3000 and 6000 m) on wear behavior were investigated. It was noticed that the wear resistance of coatings containing 1wt % of CeO2 was higher than other coatings. Further, it was found that modified coating with optimum addition of cerium oxide (1wt % CeO2) refined the microstructure, promotes the formation of hard carbides CeC2, Cr23C6 and Cr7C3, enhanced microhardness to 17% as compared to unmodified.

The dissimilar aluminium alloy sheets of 5xxx and 6xxx series are commonly used for the industrial applications in the marine, aerospace, and automobile sector due to its excellent physical and mechanical properties. In the present research, four dissimilar aluminium alloys (AA) such as 6082-T6, AA5083-O, AA6082-O, and AA5052-H32 having 2 mm thick sheets were used. The uniaxial tensile tests were performed to evaluate the plastic strain ratio (r), anisotropy (mean, normal, planar), strength coefficient (K), and strain hardening exponent (n) of materials. During the calculations of anisotropy, n, and K value, the samples were oriented at 90˚,45˚, and 0˚ with respect to the rolling direction of the sheet to determine the influence of material properties on sheet metal forming. It has been observed that the direction of the fracture line was completely dependent on the anisotropy ratio of blank in the tensile test. The comparative study has been made to evaluate the anisotropy, n, and K value of each aluminium alloys. It was found that these material properties were a good correlation with the formability effect of the sheets.

The research focus in almost all applications is currently high-entropy alloys (HEAs). HEAs comprise several main elements which can extend considerably more than conventional alloys by the possible number of HEA compositions. Different alloy structures with improved property combinations have been explored in the last 15 years to identify HEA systems, resulting in an extraordinary development of this area. This paper discusses a few essential topics in the field: core effects, phase development, mechanical features, high temperature, and corrosion behavior. It also outlines existing issues and future recommendations for product technology and research.

The objective of this present work is to the comparison of simulation and experimental results on the formability behaviour of dissimilar aluminium alloys such as AA6082-O, AA5083-O, AA5052-H32 and AA6082-T6 using limiting dome height (LDH) test. This research work is divided into four main parts. In the first part, experiment is performed on LDH test is used to predict the failure criteria of formability of all aluminium alloys. The experimental dome height values were measured and recorded. In second part, the uniaxial tensile test for all aluminium alloys was performed, and the combined curve of true stress–strain values and force-displacement was drawn. In third part, the simulation of LDH test is performed on simulation using Hyperform software to estimate the forming behaviour of used aluminium alloys. In simulation process, the comparative study of forming limit diagram (FLD), plastic, minor and major strain of used aluminium alloys was studied. With the help of simulation result, the forming limit curves (FLC) were drawn to develop the minor and major strain paths. In last part, the comparison of simulation and experiment result of dome height was prepared when localized necking occurs. It is showed that the simulation results have a good agreement with the experimental result at 93% accuracy for all aluminium alloys. Both the result shows that the AA6082-O has better formability followed by AA6082-T6, AA5083-O and AA5052-H32.

Electromagnetic stir casting is one of the simplest ways of producing defect free aluminum matrix composites. This work focuses on the fabrication of aluminum matrix composites reinforced with various weight percentages of SiC particulates and Fly-ash by modified electromagnetic stir casting route. The distribution of SiC and Fly-ash particles in the matrix was improved by providing externally argon gas into the melt during electromagnetic stirring. Five samples of hybrid composite with different combination of Fly-ash and SiC (25 μm) were prepared by electromagnetic stir casting method. Mechanical properties (tensile strength, hardness, toughness and fatigue strength) and microstructure of all five samples were analyzed. Microstructure presents that the reinforcements (SiC particulates and Fly-ash) are uniformly distributed in the matrix (A356). The results reveal that sample of A356/15 %SiC/5 % Fly-ash shows best result among all the selected samples. Density, porosity, specific strength and thermal expansion were also calculated to see the effect of Fly-ash addition.

Green tribology plays important role in the field of saving energy and development of sustainable material. The coefficient of friction and wear of the material at the interface of two mating surfaces exists according to the application methodology. The effective lubrication at the interfaces of materials having relative motion reduce friction and wear and impart major role in achieving energy saving, increase of operational life of material. Thus, the emerging trend is to design interface profile to achieve better and efficient surface. The mathematical model has been employed for the analysis of performance parameters at the lubricated interface developed between plain surface and another had either exponential or cubical face profile. The result of the performance parameters has been numerically investigated and discussed. Based on the numerical analysis, it was observed that exponential face profile has proved much energy efficient than cubical face profile Thus, exponential face profile has better Tribological performance than cubical face profile.

Ni-based alloys are being widely used to improve the wear resistance of various industrial components in normal and severe environments and addition of rare earth elements to these alloys further improves the various mechanical and tribological properties of the coatings. In the present work, commercially available MEC 86 (NiCrBSi/WC–Co = 65/35) powder was modified with the optimum addition of 0.4 wt.% La2O3. The coatings were deposited by high velocity oxy-fuel (HVOF) spraying process. Rare earth addition refines the microstructure and increases the microhardness of the coatings. The increase in microhardness with the addition of La2O3 is approximately 22%. Sliding wear resistance of the coating modified with La2O3 is higher than of that without La2O3. The average wear resistance increases by approximately 14%. Further, the addition of La2O3 to the coating reduces the friction coefficient as compared to the one without the rare earth element. The coefficient of friction was found lower with the addition of La2O3, which is approximately 18%.

AA6082 matrix hybrid composites reinforced with different weight percentages (wt. %) of (SiC + Gr) ceramic particulates by conventional stir casting process is manufactured. The weight percentage of ceramic powder is varied from 4 wt. % to 12 wt. % in a stage of 4 wt. %. The microstructures, physical properties such as density and porosity, as well as mechanical properties like hardness and tensile strength of the fabricated hybrid composites, are analysed. The optical micrographs reveal the uniform distribution of (SiC + Gr) ceramic particulates in the aluminium matrix. Density and porosity of hybrid composite increases from 2.69 to 2.75 g/cm3 and 0.37% to 1.23% with increase in weight percentage of (SiC + Gr) ceramic particulates in the aluminium matrix from 0 wt. % to 12 wt. % respectively. Both the hardness and ultimate tensile strength have enhanced from 52 to 84 VHN and 163 to 189 MPa, respectively, with a reduction in percentage elongation from 8.6 to 5.2 with rise in weight percentage of (...

The use of industrial-agro wastes as reinforcements in the development of composites can be considered as a new inclination in the field of material research. The present investigation involves the development of AA6351 mono-composites with various weight percentages (2wt.%, 4wt.%, 6wt.% and 8wt.%) of silicon carbide (SiC) and rice husk ash (RHA) as reinforcement using stir casting technique. The physical, microstructural, mechanical and tribolological behaviour of the developed composites were examined for the both type of the composites. An increase of 1.08% in density, 37% in hardness and 39% in tensile strength was recorded for the composites developed with silicon carbide as reinforcement and a decrease in density of 3.9%, an improvement of 16% in hardness and 21% in tensile strength was indicated for the composites reinforced with rice husk ash as reinforcement. The results also revealed a uniform distribution of the reinforcement and improved wear resistance for the both set of the composites. The characterization results exhibited that even the performance of the composites with SiC as reinforcement is better than the performance of the composites with RHA as reinforcement but RHA can be suitably applied as reinforcement for the development of low density AA6351/RHA green composites

The effect of waste carbonized eggshell and silicon carbide (SiC) wt.% on the dry sliding wear behavior of AA2014 alloy green composites produced by electromagnetic stir casting method was investigated. The percentage of waste carbonized eggshell particles and SiC particles varied from 2.5% to 12.5%. The tribological behavior of AA2014/waste carbonized eggshell/SiC hybrid green metal matrix composites (MMCs) was investigated on a pin-on-disc apparatus. The weight percentages of waste carbonized eggshell and of SiC, normal load, and sliding speed and distance were taken as input process parameters, and wear rate was taken as a response. Response surface methodology was used to plan and analyze the experiment. Minimum wear rate was found to be 8.89×10−5mm3/m with desirability one at optimum parameters of 1.75 m/s (sliding velocity), 6.5 (carbonized eggshell wt.%), 34.24 N (normal load), 1219.63 m (sliding distance), and 11 wt.% (SiC wt.%). In the confirmation experiment, the experimental wear rate of the hybrid green MMC at optimum parameters was found to be 9.5×10−5. Results showed that the experimental wear rate and density of the hybrid green MMC were reduced by about 36.66% and 0.35%, respectively, compared with the matrix.

In this Present work dry sliding wear tests on specimens of Mild Steel, WC-12Co and WC-10Co-4Cr coated specimens were performed against a hardened EN32 steel disc under dry sliding conditions. High Velocity Oxy-Fuel flame spraying technique (HVOF) was used to deposit the coating on 1020 grade steel then theses coated sample characterized using scanning electron microscopy, X-ray diffraction (XRD), coefficient of friction (COF), hardness The experiment result show MS specimen suffered high wear loss, but the WC-Co and WC-Co-Cr specimen showed negative wear and higher friction coefficient .Hardness is higher in the WC-12Co coating than in the WC-10Co-4Cr coating. The SEM image shows the bright and dark grey regions corresponding to tungsten carbide and cobalt binder phase XRD result shows that decomposition of WC (into W2 C and W) cases lower wear

The application of natural fibers such as Jute/bagasse with glass fiber hybrid advanced composites has gained increasing interest both in many areas of engineering and technology. Hybrid plates of two compositions, i.e., Jute fiber mat-chopped glass fiber and Chopped Bagasse-glass fiber mat with epoxy as a matrix were fabricated using hand lay-up technique and their mechanical properties were evaluated. Tensile strength (TS), tensile modulus (TM), elongation at break (Eb%) and hardness of the composite samples were evaluated as per ASTM standards. Moisture absorption capacity for the above two compositions have been found out by hygrometric principle and it was concluded that the water absorption increased as the weight% of natural reinforcement increased. Degradation test has been carried out by burying the samples for different period (15–30 days) in the soil and it was found that as the weight% of natural fiber reinforcement increased the degradation rate increased. Tensile strength was found to be increased (11%) by alkali (NaOH) treatment of the natural fiber. The composite specimens were also immersed in the water for 24 hours and decrement in the tensile strength was noted. Microscopic examinations were carried out to analyse the interfacial characteristics of materials, internal structure of the fractured surfaces and material failure morphology by using Scanning Electron Microscope (SEM).

Ultrathin porous carbon nanosheets (PCNs) with large aspect ratio and hierarchical porous layered structure provide numerous catalytic active sites along with chemical stability, large surface area and high electrical conductivity that is ideal for energy conversion and storage devices. The doping of PCNs with nitrogen and other heteroatoms improves the electrocatalytic properties needed for energy applications. However, routine synthesis methods based on molecular assembly or templates yield only small samples that restricts the use of PCNs in flexible electronics and energy devices and moreover, the use of toxic etching agents to remove templates is not environment-friendly. Therefore, the scalable and low-cost production of highly active and robust biomass-derived PCNs is of paramount importance and it can be achieved by the use of low-cost, abundantly available, sustainable biomass. In the present article, biomass-derived PCNs and their N-doping has been reviewed for energy applications, primarily as oxygen reduction reaction catalysts in fuel cells and as electrodes in supercapacitors. The synthesis of PCNs from twenty biomasses, ten for each application, and their N-doping by conventional (using ammonia or urea) and self-doped green (using biomass) approach has been discussed. In the green approach, same biomass is used as C as well as N (or heteroatom) precursor for N or heteroatom-doping of PCNs and it has recently emerged as a very promising green strategy for the scalable synthesis of N-doped PCNs from biomass. It can be further tuned to develop advanced carbon nanomaterials from diverse biomass materials for various sustainable energy related applications.

Heteroatom-doped carbon materials, despite showing excellent performance as oxygen reduction reaction (ORR) catalysts, are not commercially viable in fuel cells due to their high cost and use of hazardous materials during synthesis. The earth-abundant renewable and sustainable biomass can be a low-cost carbon precursor for the synthesis of activated porous carbons with high surface area, ordered porosity and tunable pore sizes and could provide a good alternative to platinum-based catalysts. Coconut shell is one of the best-known biomass for the production of high quality porous activated carbon, owing to its unique cellular structure. Further, the surface area and porosity of biomass-derived porous carbons can be fine-tuned and optimized by controlling synthetic parameters during the pyrolysis, carbonization, and activation. Nitrogen doping of porous carbons can further enhance their ORR activity. The review focuses specifically on the activation and tuning of coconut shell-derived porous carbons as ORR catalysts, a topic not yet thoroughly evaluated in other reviews of biomass-derived activated carbons. In this review, (i) various activation methods, including self-activation to avoid the use of harsh chemicals for developing desired pore structures, (ii) control of porosity and nitrogen doping to improve ORR catalytic performance, (iii) use of microwave heating to reduce synthesis time, energy and cost, and (iv) scalable production of porous carbons for different applications are discussed.

The use of metal–matrix composites are increasing day by day as compared to the alloys, on account of their superiority in terms of properties like hardness, tensile strength, wear resistance and corrosion resistance etc. Reinforcement plays a very important role in deciding the properties of the composites produced. This paper focuses on the literature review of monolithic and hybrid metal–matrix composites produced using a variety of industrial-agro wastes as reinforcement materials and the effects of these reinforcements on the physical, microstructural, mechanical and tribological properties of the developed composites. The literature results revealed that the utilization of these industrial-agro wastes as reinforcement materials improved the overall performance of the developed composites and helped in reducing the overall cost of reinforcement also. The concluding part of the paper discusses the applications and the potential utilization of these wastes as reinforcement materials for the future research work.

The AA2014/5 wt. % carbonized eggshells metal matrix composite used in this study was fabricated by electromagnetic stir casting technique and immediately extruded on universal testing machine at 60 MPa using cylindrical H13 tool steel die coated with graphite to avoid upper flow of eggshells particles and to improve wettability of eggshells with AA2014 alloy. Microstructures of composites show some agglomerations in non-extruded samples while uniform distribution of carbonized eggshell particles. Optimum combination of precipitation hardening parameters achieved using response surface methodology to further improve the properties of AA2014/5 wt. % eggshell composites. Optimum values of solutionizing time, aging temperature and aging time were found to be 4.5 h, 250℃ and 13.5 h, respectively. More grain refinement of extruded AA2014/5 wt. % eggshell composites were observed after heat treatment at optimum precipitation hardening parameters. After heat treatment, fractographs of the AA2014/5 wt. % eggshells composite showed that fracture is dominated by trans-granular type. Density of the AA2014 is 5% higher than AA2014/5 wt. % eggshells metal matrix composite. It is observed that mechanical properties improve when carbonized eggshell particles are reinforced in matrix AA2014 aluminium alloy. After the heat treatment at optimum precipitation hardening parameters, mechanical properties are further improved.

Nickel base alloys are being widely used to improve the abrasive and adhesive wear resistance of various industrial components. In the present investigation, commercially available Ni-base (nickel-base) powder (MEC 1260) was used for coating deposition. The coating was deposited by flame spraying process. The microstructure of the flame sprayed coating mainly showed Ni-cells surrounded by eutectic. The Ni (nickel), Cr (chromium) and Fe (iron) were uniformly distributed in the coating while the distribution of boron was found along the grain boundaries. The Rockwell hardness of the coating was found as 56±8 (HRc). Sliding wear resistance of coating is 3-4 times higher than substrate.

The current research work scrutinizes aluminium alloy 6101-graphite composites for their mechanical and tribological behaviour in dry sliding environments. The orthodox liquid casting technique had been used for the manufacturing of composite materials and imperilled to T6 heat treatment. The content of reinforcement particles was taken as 0, 4, 8, 12 and 16 wt.% of graphite to ascertain it is prospective as self-lubricating reinforcement in sliding wear environments. Hardness, tensile strength and flexural strength of cast Al6101 metal matrix and manufactured composites were evaluated. Hardness, tensile strength and flexural strength decreases with increasing volume fraction of graphite reinforcement as compared to cast Al6101 metal matrix. Wear tests were performed on pin on disc apparatus to assess the tribological behaviour of composites and to determine the optimum volume fraction of graphite for its minimum wear rate. Wear rate reduces with increase in graphite volume fraction and minimum wear rate was attained at 4 wt.% graphite. The wear was found to decrease with increase in sliding distance. The average co-efficient of friction also reduces with graphite addition and its minimum value was found to be at 4 wt.% graphite. The worn surfaces of wear specimens were studied through scanning electron microscopy. The occurrence of 4 wt.% of graphite reinforcement in the composites can reveal loftier wear possessions as compared to cast Al6101 metal matrix.

In the present investigation the microwave hybrid heating process was used to develop coatings on P20 tool steel substrates. The experiments were carried out in a domestic microwave oven of 900 W and 2.45 GHz frequency for a duration of 360 s. Ni-based clads/coatings without cerium oxide (CeO2;unmodified coating) and with the addition of CeO2 (modified coating) with varying wt.% of 1–3 were developed by the microwave hybrid heating process. The effect of CeO2 addition on the microstructure, X-ray diffraction, and Vickers hardness, and the abrasive wear behavior of the developed clads was studied under varying sliding speeds and grit sizes. Investigation showed that the optimal addition of CeO2 (1 wt.%) can effectively improve the microstructure, hardness, and abrasive wear behavior of the coatings. The Vicker’s microhardness of the modified coating with 1 wt.% of CeO2 was 30% higher than the unmodified coating. Abrasive wear resistance of the modified coatings was found higher with an optimal addi...

This paper deals with the fabrication and characterization of thermo-mechanical properties of boron carbide reinforced aluminum matrix composites. The effective elastic moduli and effective coefficients of thermal expansion (CTEs) of 4, 8 and 12 vol% boron carbide reinforced aluminum matrix composites were measured experimentally. Object oriented finite element method (OOF) is used next to determine the effective material properties and the effects of microstructure morphologies, i.e., shape, size and orientation of reinforced particles and the presence of voids is analyzed. Different microstructures are constructed for finite element analysis using scanning electron microscopic images of composites. The results obtained from finite element modeling are compared with the experimental values.

Springback effect is the most sensitive feature in sheet metal forming. There are many input process parameters of die and press, which affect the springback/go. In the present study, three different aluminium alloys (AA), namely AA6082-T6, 5083-O and 5052-H32, are used. The objective of this work is to compare the effect of process parameters of V-bending die on springback by using Taguchi method. Bending angle (BA), punch load (PL) and punch velocity (PV) were taken as input process parameters. Taguchi approach and ANOVA (analysis of variance) were applied to find the most significant parameter(s) which affects the output response, that is, springback/go in V-bending process. The experiments were performed on V-bending die using a blank size 40 × 100 × 2.0 mm3 and the springback/go value was calculated using optical microscope. Taguchi L9 orthogonal array design of experiment was applied to all aluminium alloys AA6082-T6, AA5052-H32 and AA5083-O and the experiments were performed separately. The result shows that the bending angle is the most significant parameter affecting the springback/go value with a contribution of approximate 99% for all aluminium alloys. The optimal values obtained for springback/go for AA6082-T6 at 120° BA, 4 KN PL and 8 mm/s PV, for AA5083-O at 120° BA, 2 KN PL and 24 mm/s PV and for AA5052-H32 are 120° BA, 4 KN PL and 8 mm/s PV.

Micromilling is one of the preferable micro-manufacturing process, as it exhibits the flexibility to produce complex 3D micro-parts. The cutting forces generated in micro end milling can be attributed for tool vibration and process instability. If cutting forces are not controlled below critical limits, it may lead to catastrophic failure of tool. Cutting force has a significant role to decide the surface roughness. Therefore accurate prediction of cutting forces and selection of suitable cutting parameters mainly feed, is important while micro end milling. In present study, finite element method (FEM) based model has been developed by using ABAQUAS/Explicit 6.12 software. Von-Misses stresses and cutting forces are predicted while micro end milling of Ti-6Al-4V. Further, cutting forces were measured during experimentation using dynamometer mounted on micro-milling test bed. Cutting forces predicted by FEM model are in good agreement with the experimental force values. Obtained FEM results have been used to study the size effect in micro end milling process. Moreover, the effect of uncut chip thickness to cutting edge radius ratio (h/rc) on surface roughness (Ra) has been studied. It is found the feed 2.5 µm/tooth is suitable value to produce optimum surface roughness and cutting forces.

The mechanical behavior, physical behavior, microstructural characteristics, and corrosion behavior of AA2014/silicon carbide (SiC)/carbonized eggshell hybrid green metal matrix composites (MMCs) were investigated. Twenty-five samples of hybrid composite with different combinations of SiC and carbonized eggshell particles in AA2014 matrix alloy were prepared. Microstructure presents that the reinforcement particles (SiC and eggshells) are uniformly distributed in the matrix AA2014 alloy. Transmission electron microscope image shows proper wettability between SiC, carbonized eggshell, and AA2014 aluminum alloy. The tensile strength and the fatigue strength for the composites containing 2.5 wt.% SiC up to 7.5 wt.% carbonized eggshell were observed to be higher than that of the other selected composites. The hardness values for the composites containing 12.5 wt.% SiC and 2.5 wt.% carbonized eggshell were in all cases higher than that of the other composites. The results show that toughness decreases with the increase in the weight ratio of SiC and carbonized eggshell in the composites. The results reveal that the sample of AA2014/2.5% SiC/12.5% carbonized eggshell shows minimum corrosion rate among all the selected samples. Density, porosity, and overall cost of hybrid metal matrix composites were also calculated to see the effects of carbonized eggshell and SiC addition in AA2014 matrix alloy.

The aim of the present study is to investigate the effect of microwave energy on the structural and electrical properties of yttria-stabilized zirconia (YSZ) electrolyte for solid oxide fuel cells (SOFC). Five different compositions of Zr1−x Y x O2−x/2 (x = 0.06–0.14) were prepared by a co-precipitation method and were then sintered by microwave as well as conventional heating at 1400°C for 20 min and 240 min, respectively. The structural and electrical properties of the samples sintered by both the methods were compared. The x-ray diffraction (XRD) results revealed that YSZ samples sintered by both methods had either a tetragonal crystal structure or a cubic structure depending on its composition. Almost the same degree of densification as well as conductivity of same order was found from impedance analysis for both microwave- and conventionally sintered YSZ products, which showed that microwave sintering is the better alternative for material processing in terms of saving energy and time without compromising the product quality.

Three AA2014 alloy metal matrix composites containing reinforcing particles of eggshell, carbonized eggshell and CaCO3 (powder) were processed. The influences of different particle percentage of eggshell were compared with commercial calcium carbonate. The electromagnetic stir casting technique followed by hot extrusion was employed to fabricate metal matrix composite. The results revealed that the tensile strength, hardness and fatigue strength increased by the addition of eggshell particles up to 12.5 wt.% in AA2014 matrix alloy for both carbonized and uncarbonized reinforced composites. Toughness, ductility and corrosion rate decreased by the addition of eggshell particles up to 12.5 wt.% in AA2014 matrix alloy for both carbonized and uncarbonized reinforced composites. Mechanical properties decreased in the addition CaCO3 in AA2014 matrix alloy. After the heat treatment process, mechanical properties further improved for both carbonized and uncarbonized eggshell particles reinforced composites. However, corrosion rate increased. These results showed that using the carbonized eggshell as reinforcement in the AA2014 alloy gave better physical and mechanical properties at lower cost as compared to uncarbonized ES particles and CaCO3. Apparent interfacial reaction layer and minimum corrosion were observed at AA2014/12.5% carbonized eggshell particulate composite. No reaction product was observed at AA2014/CaCO3 particulate metal matrix composite.

The present work aims to investigate the influences of thermal residual stresses and material properties on the thermomechanical deformation behavior of Al–B4C composites. Boron carbide-reinforced aluminum matrix composites having 4, 8, and 12 vol% boron carbide were fabricated using squeeze liquid stir casting method for experimental characterization of their microstructure, effective elastic moduli and effective CTEs at room temperature as well as elevated temperatures. Next, the thermomechanical behavior of fabricated composites was investigated using finite element modeling. The effects of thermal residual stresses on the effective material properties were examined by simulating the cooling process of MMCs from processing temperature to room temperature. The effective elastic moduli and the effective CTEs were predicted considering linear elastic as well as elastoplastic deformation of aluminum matrix, and the results obtained were compared with the experimental values. The effects of voids on effective material behavior are studied by simulating the void growth and nucleation using Gurson–Tvergaard–Needleman model.

The influences of weight percentage of different reinforcement particles such as SiC particles, waste uncarbonized eggshell particles, carbonized eggshell particles, and CaCO3 powder were compared in the processing of aluminium-based metal matrix composite. The results revealed that by the addition of SiC particles up to 10 wt.% and waste eggshell particles up to 12.5 wt.% in AA2014 matrix alloy, the tensile strength, hardness, and fatigue strength increased. Toughness and ductility decreased by the addition of SiC and eggshell particles in AA2014 matrix alloy. Corrosion rate decreased by the addition of SiC particle up to 7.5 wt.% and eggshell particles up to 12.5 wt.%. Results showed that hardness and heat-treatable properties are improved after the addition of SiC reinforcement particles in AA2014 aluminium alloy as compared to eggshell particles. However, porosity and overall cost increased after addition of SiC particles in AA2014 alloy. Corrosion rate increased after the heat treatment for all reinforced metal matrix composite. These results showed that using the carbonized eggshell as reinforcement in the AA2014 alloy gave better physical properties at lower cost as compared to SiC particles. Proper wettability was observed between matrix and reinforcement material for both carbonized eggshell particles and SiC particles. No wettability was observed between AA2014 alloy and CaCO3 reinforcement particles. Poor wettability reduced the mechanical properties of AA2014/CaCO3 metal matrix composite.

Chicken eggshell (ES) is an aviculture byproduct that has been listed worldwide as one of the worst environmental problems. The effective utilization of chicken eggshell (ES) biowaste is strongly encouraged in our society for environmental and economic reasons. The present work deals with development of AA2014/carbonized eggshells particulate composites by electromagnetic stir casting process at optimized parameters using RSM. The predicted tensile strength of 239 MPa of the composite was found at optimum parameters of 60 MPa (Squeezing Pressure), 12 ampere (Current), 180 s (Time) and 700°C (Pouring Temperature) respectively. There was about 2.79% error in the experimental and modeled results of tensile strength. Obtained result shows that as stirring current and stirring temperature increases, tensile strength also increases. While increase in pouring temperature of matrix decreases tensile strength of composite. Density of the metal matrix composite decreases 5%, when eggshells particulate is added 5% by wt. to matrix alloy. Hardness, toughness and fatigue strength were also carried out of the AA2014/eggshell composite. Results show an improvement in these properties with the addition of eggshell in the matrix alloy. Microstructural study show uniform distribution of eggshell in the composites.

In the present investigation, joining speed, laser power and stand-off distance were took up as joining process parameters in determining the laser transmission joining between PET films and 316 L stainless steel plates. The laser transmission joining process parameters were optimized using response methodology for obtaining maximum joint width. The Box-Behnken Design has been used to plan the experiments and response surface methodology (RSM) is selected to develop mathematical relationships between joining parameters and desired response (joint width). From the ANOVA (analysis of variance) it was concluded that stand-off distance is contributing more and it is followed by joining speed and laser power. In the range of process parameters, the result shows that joining speed increases, joint width decreases, while with the increase of laser power and stand-off distance, joint width increases. Optimum values of joining speed, laser power and stand-off distance was found to be 100 mm/min, 18 watt and 3 mm to get the maximum joint width (Predicted 2.232 mm). Corresponding average tensile strength of joint was found to be 84.38 MPa. There was approximately 6.61 % error in the experimental and modeled results of joint seam width.

In this paper an elastoplastic finite element model for studying the thermomechanical behavior of Al/Al2O3 particulate composites is proposed. 3D representative volume elements (RVEs) are created to model the microstructures of Al/Al2O3 composites and the finite element models generated from RVEs are used to study the mechanical and thermal expansion properties. In order to study the effect of thermal residual stresses, first the RVEs are simulated for cooling process from sintering temperature to room temperature and thermal residual stress are estimated for different mechanical behaviors of Al matrix. Next, the thermomechanical properties are examined with existing residual stresses. The predicted effective elastic moduli and the coefficient of thermal expansion are compared with the experimental results reported in literature. The FE results have good correlation with the experimental data and the effects of microstructural parameters, voids and properties of the constituents are further discussed. In order to study the influence of voids on the elasto-plastic behavior of composites, the Gurson–Tvergaard–Needleman (GTN) model is applied. The nucleation and growth of voids in composites, under uniaxial tension, is studied.

Co-based alloy modified with La2O3 is deposited by high velocity oxy-fuel (HVOF) spraying rocess. The microstructure, porosity, hardness, and abrasive wear of the coatings are investigated. The La2O3 addition refines the microstructure, forms new phases, and increases hardness and abrasive wear resistance of the modified coating. The abrasive wear behavior of these coatings is investigated under normal loads 5 and 15 N against 220 abrasive grit size. The abrasive wear is carried out using 30 and 50 m/min sliding rates. The abrasive wear is found to increase with the increase in normal load and sliding rates. Analysis of the worn surfaces by scanning electron microscope images revealed cutting and plowing as the material removal mechanisms in these coatings under abrasive wear conditions used in this research.

The present research work emphasizes the development of hybrid aluminum (AA6082) matrix composites (HAMCs) reinforced with different weight percentages (wt.%) of ball-milled (silicon nitride (Si3N4) + graphite (Gr)) ceramic particulates by conventional stir casting process. Si3N4 and Gr are ball milled to obtain a definite density of combined powder. The weight percentage of ball-milled ceramic powder is varied from 0 to 12 wt.% in a stage of 3%. The microstructures as well as mechanical properties of the fabricated hybrid composites are analyzed. The scanning electron micrograph reveals the uniform distribution of ball-milled (Si3N4 + Gr) ceramic particulates in the aluminum matrix. The distribution of ball-milled (Si3N4 + Gr) ceramic particulates has also been analyzed with x-ray diffraction (XRD) technique. Both the hardness and ultimate tensile strength have enhanced with a reduction in percentage elongation with increase in weight percentage of ball-milled (Si3N4 + Gr) ceramic particulates in...

The effect of graphite particles on the dry sliding wear behaviour of Al6082 alloy composites produced by conventional stir casting method has been investigated. The percentage of reinforcement was varied from 0% to 12% in a step of 3. The result showed that with the addition of graphite particles micro- and macro-hardness reduced by 11.11% and 10.44%, respectively. The tribological behaviour of composites was investigated by pin on disc apparatus. Percentage reinforcement, load, sliding speed and sliding distance were taken as the process variable. Response surface methodology has been used to plan and analyze the experiment. Results showed that sliding distance is the most influential factor and load is the factor which affects the wear least.

In this study, copper plates were welded using the microwave technique, and brass material was used as an interface. The response surface methodology was used to optimize the microwave parameters for maximum joint strength, which resulted in a value of 264 MPa in 350 s. The welding temperature was maintained at 1,100°C for maximum joint strength using a single microwave oscillator with a rated power of 890 W. A Hardness test was carried out, and the tested parameter was 79 BHN, which is a better result compared with traditional welding. The corrosion behavior of the copper welded joint was also observed to be an effect of brass when used as an interfacial material between the copper plates. Weight loss of the heat-affected zone in salt solution (5 % NaCl + 95 % water) after 96 hours was found to be zero. This result indicates that brass as a filler material also enhances the corrosion resistance of the welded joint.

The energy dissipation potential of a metallic damper largely depends on the hysteretic response achieved due to the inelastic deformation of plates under either axial or flexural or shear loading. In this study, a passive energy dissipation device consisting of a series of steel plates capable of yielding in both flexure and shear has been experimentally investigated under cyclic loading. Two end plates of X-configuration are allowed to yield under flexural action, whereas a rectangular web plate of the device is allowed to dissipate energy through shear yielding. Three shear-and-flexural yielding damping (SAFYD) devices are studied by varying the size of both flexure and shear plates. The main parameters investigated are load-carrying capacity, hysteretic response, energy dissipation, equivalent viscous damping, and ductility. A finite element analysis has been carried out to predict the ultimate resistance and hysteretic response of the test specimen. The predicted results matched reasonably well with the test results. Finally, a design procedure has been proposed to proportion the flexure and shear plates of SAFYD devices for a given lateral load demand.

Commercially available multiwall carbon nanotubes (MWCNTs) have been functionalized with poly(diallyl dimethylammonium) chloride (PDDA), a nitrogen containing polyelectrolyte by a simple on-off ultrasonication method. The results obtained from Raman and X-ray photoelectron spectroscopy (XPS) studies confirm the functionalization of MWCNTs with PDDA. An up- shift in the positions of C1s XPS peak and a down-shift in the positions of the N1s XPS peak, has been observed along with an up-shift in the G-peak position in the Raman spectra, which suggest the occurrence of inter-molecular charge transfer from carbon atoms in MWCNTs to N + centres in PDDA. The preliminary linear sweep voltammetry (LSV) results show good electrocatalytic activity of MWCNTs functionalized with nitrogen containing polyelectrolyte, which is comparable to the results with platinum based electrodes. Thus, MWCNTs non-covalently functionalized with a nitrogen containing polyelectrolyte (PDDA) by a simple on-off ultrasonication method could be advantageous for developing efficient metal-free electrocatalysts for the oxygen reduction reaction (ORR).

This work focuses on the effect of graphite particle addition on the properties of AA6082 metal matrix composites fabricated by conventional stir casting method. The percentage of reinforcement was varied from 0% to 12% in a step of 3%. The results revealed that with the addition of graphite particles, the micro- and macro-hardness decreased by 11.11% and 10.44%, respectively. The ultimate tensile strength also decreased by 5.88% with a reduction in percentage elongation from 8.7 to 6.8. The density decreased by 4.1% with an increase in porosity from 0.37% to 2.27% as the weight percentage of graphite particles increased from 0% to 12%.