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It is very difficult to handle composite material using cutting edge process. The surface defects, fibre – matrix delamination, fibre pullouts and bulk material removal are some of the common effects while machining composite material. To reduce such machining effects, an advanced machining processes are suggested for difficult to cut composite materials. In this research, a hybrid natural fibre composite material is developed inhouse to study the performance of machinability through abrasive water jet cutting process. The natural composite material is developed with two filler materials such as palm and coconut shell powder. During machining the water jet pressure, nozzle traverse speed and standoff distance are varied to predict the optimal process condition. Further the unit production cost for two different combination of material is optimized using a natural evolutionary based genetic algorithm. It was found that the unit production cost for 10 wt% filler reinforce natural fibre composite yields maximum production cost compared to 7.5 wt% filler material reinforcement for nearby machining process parameters. The variation in production cost is due to the influence of mechanical cum metallurgical quality, distribution and densification of filler material reinforced. The level of experiments is also validated using regression analysis.

Surface technology is making emerging trends in engineering environment. Wax-epoxy coatings are one of the surface improvers, which are also found in nature and appear on plant leaves, such as lotus leaf and some insect wings. The present study was focused on this stream line where the effect of the fumed silica addition into the rice bran (RB) wax-epoxy coating on aluminum substrate. The main aim of the present study was to find how the addition of RB wax modified the base properties of epoxy resin and what could be the significant of adding fumed silica as strength booster. The coatings were done using spray coating technique at ambient temperature. According to the results, the addition of RB wax into the resin along with fumed silica improved the mechanical, hydrophobic nature, thermal stability, and wear resistance. A highest flexural strength of 102 MPa, lap shear strength of 21.65 MPa, microhardness of 88 shore-D, Sp. wear rate of 0.003mm3/Nm, and the lowest COF of 0.38 were noted for composites made using rice bran and fumed silica particle. The density remains same due to low density wax material addition with noticeable improvement in surface hardness. The SEM micrographs revealed flat fractograph for pure epoxy and high wavy structure for wax mixed fumed silica dispersed epoxy coating. The surface roughness of coated surfaces explicated less surface roughness than uncoated one. These eco-friendly coatings could be used in automobile, medial, and biological applications.

Thermal barrier coatings are widely used as surface modifications to enhance the surface properties of the material and protect from surface degradations such as erosion and corrosion. Ceramic-based coatings are highly recommended to increase wear resistance in the industrial sector. In this paper, an alumina-titania ceramic powder was deposited on an aluminum alloy using an atmospheric plasma spray technique. Experimental investigations were performed to study the behavior and erosion rate of the material. Solid particle erosion studies were performed by varying the particle velocity and particle flow rate. The angle impingement and stand-off distance were constant for comparison. The base metal has a clinging effect and the mass change was negative at a maximum particle flow rate of 4 g·min−1. Under the same process conditions, the coated sample had a reduced lifetime and reached a maximum erosion rate of 0.052 (Δg/g). The solid particle erosion studies confirmed that the base metal aluminum alloy had severe surface damage with erodent reinforcement when compared to the coated samples. The influence of the particle velocity, particle flow rate, and input process parameters were also identified.

In this investigation, electroless Ni-P was deposited on mild steel in presence of magnetic field, a modified coating technique. Degree of crystallinity was measured through integrated intensity, Full Width at Half Maximum and integral breadth with the help of profile fitting. The data which are taken from the x-ray diffraction profile was used to find the crystallite size and microstrain using the in-house software ‘PROFAN’. The presence of the magnetic field modified the Crystallization behaviour of the Electroless Ni-P both in as coated and heat treated conditions.

As per the survey of the World Energy monitor issue 2019 portrait that since 1975, there was a rapid growth in the energy demand around the world till now and it is mainly satisfied by fossil fuels and centralized power generation. In the future, there should be varied energy transition need to happen to decrease the usage of fossil fuel. In this regard, much research work had been going on to ensure proper energy consumption without wasting much energy. Nowadays research on coating techniques was evolved to control the waste heat emission and to reduce corrosion reduction in pipes to conserve the most energy-releasing as an unused. In that, the usage of nanoparticles as a coating material in the area of heat transfer applications were evolved to enhance its working capacity. This review paper depicts the results obtained by various researchers with the usage of nanoparticles as coating materials over the other materials to enhance the thermal and corrosion properties by exploring with diverse nanoparticle size, coating thickness, morphological characteristic detecting instruments and usage of nanoparticles in diverse applications were studied. This paper may give the researchers a basic idea to pick the valid coating materials with their properties and applications for their study in heat transfer equipment.

This review paper aims to portray the work done by various researchers in the domain of thermal barrier coatings. Thermal barrier coatings (TBCs) are provided to minimize the temperature of components in the field of aviation and power generation sector to increase the components performance and efficiency. The review was made in the aspects of methodology adapted for the coating process, thickness of various coatings, materials chosen for coating, anatomy of TBC and mechanism of thermally grown oxides (TGO). Based on the survey, majority of the articles are found employed the process of spray coating for TBC. On the hand, literatures depicts that the preferred materials for TBS is ceramics due to lack of thermal conductivity and high corrosion and wear resistance. The review expose that the TBCs are more resistant to oxidation, corrosion, erosion and it act as a good thermal insulator to protect the material high temperature environment.

This study aims to understand the electrochemical behavior of the Wire Electro Spark Eroded Ni55Ti45 alloy. The WESE machining process had been performed by considering the spark on time, spark off time and applied voltage as process parameters. The response chosen for the valuation of the machining process is surface quality. The surface properties of machined specimen were studied through the Scanning Electron Microscopy (SEM) and surface roughness meter. Then the maximum and minimum surface roughness samples were exposed to the electrochemical corrosion studies considering NaCl as the electrolyte medium. The outcomes of the corrosion result are projected in form of corrosion rate found from the TAFEL plot. Further, the surface of corroded specimens was studied using the imaging techniques.

In current scenario, the engineering materials are profound their application towards Bio-Medical field. The human implants caught the eye of researchers in the field of materials and metallurgy. After meeting the accidents, aged people’s bone crack and other factors for replacing bones is a major problem faced by the medical society. Considering the fact, researchers have found some viable alternative for the bone material which is positive towards biocompatibility. The alternative implant materials are manufacturing without compensate biocompatibility. This paper covers the trends happening in the machining of implant material through the non traditional approaches such as EDM, WEDM and some other advance technologies.

In this investigation, electroless Ni-P with diamond particle was deposited on carbon steel in presence of magnetic field, a modified coating technique. Degree of crystallinity was measured through integrated intensity and integral breadth with the help of profile fitting. The coatings were evaluated using an In-House developed software 'PROFAN. The presence of the magnetic field modified the crystallization behaviour of the composite coatings with nickel – phosphorus – diamond through electroless coating process. The treatment of composite coating is performed with different technique at different temperatures. Further, the mechanical wear of the coating is evaluated.

In this paper, the Ni – P is deposited on steel through electrolytic process. During deposition the magnetic field is used to control the deposit and the same was performed with conventional concept. The difference in magnetic field found better than the conventional process. Efficiency of the coating and the crystallinity of the coating evaluated through a standard procedure. In the case of annealing, the decrease in microstrain and the corresponding increase in crystallite size is associated with the decreasing defect content of the lattice as a consequence of recovery and recrystallization processes. This behavior of increasing both crystallite size and microstrain is distinctly different. The strains which are produced by the magnetic field by constraining the movement of atoms as mentioned earlier could be the reason for this trend.

Composite dielectrics and insulators are emerging as replacement of neat epoxy because of their superior characteristics. However, methods of composite preparation, type and size of filler and stresses such as temperature and mechanical stresses influence these characteristics. In addition, inorganic oxides-based epoxy composites are expected to have good dielectric characteristics. In this work, effect of compression and silica on the dielectric properties of epoxy composites with reference to neat epoxy is explored. Epoxy microcomposite (15% by weight silica loading) and nanocomposites (2.5% and 5% by silica loadings) are prepared, and their dielectric properties are investigated before and after compression at 15 MPa. Overall epoxy nanocomposites with 5% nanosilica performed best having 0.09 dissipation factor and dielectric constant of 6.23. After compressing the samples at 70 °C and 15 MPa, dramatic increase in the dissipation factor of microcomposites was recorded where the average $$ \kappa $$ increased by a factor of 1.53–8.27 in comparison with 5.40 in the uncompressed form.

This investigation reports the effect of mechanical deflector during coating on the mechanical properties of the Electroless Ni-P deposits. Micro hardness of the electroless Ni-P deposits was measured using shimadzu micro hardness measuring unit employing a diamond indenter and pin-on-disc wear tester was used to measure the wear resistance of the deposits. The characteristics of deposits produced in presence of mechanical deflector are found to be superior from those produced using conventional deposition techniques. Enhancement in properties are correlated with modified crystallinity and the conversion of Ni-P in to possible phosphides in the presence of mechanical deflector. It has been noticed that the coating efficiency has 30% hike with mechanical deflector. Annealing at 350ºC has reached the maximum hardness of 950 Hv and subsequent increase in wear resistance.

In this research, the austenitic stainless steel human implant materials are machined using wire electrical discharge machining process (WEDM). The machining process is controlled with optimised process parameters such as pulse on / off time and applied voltage. The responses on machining are assessed from surface quality. At the same machined surface are metallurgical evaluated for the quality of surface topography through electron microscopy (SEM) and atomic force microscopy (AFM). Further the machined surfaces are subjected to study bio-compatibility using the medium simulated body fluid (SBF). The body fluid was prepared using standard reagents and regular process followed by Kokubo procedure. The outcomes of the results are in the form of corrosion rate calculated from TAFEL plot. Surface degradation of the exposed samples are further analysed using SEM for discussion

Surface modification is a broad term which is associated with various technologies that can be exploited to achieve high reliability and performance capability of industrial components. The increasing usefulness and benefits of surface engineering has resulted in significant recent advances in the field. Among the various coating techniques, Thermal coating technique of Plasma spray process has been embraced in this work. Surface properties are enhanced with Tungsten Carbide (WC) coating over Austenitic Stainless Steel (SS316). The Plasma Spray Coating is the deposition coating technology in which solid feed stock in form of Tungsten Carbide powder of 50 µm size is introduced in hot plasma jet to form liquid droplets which are accelerated toward a substrate (SS316). The surface morphology of Tungsten Carbide (WC) coating over Austenitic Stainless steel (SS316) using Scanning Electron Microscope is discussed in this paper. Erosion wear tests and corrosion tests for Tungsten Carbide (WC) coated Austenitic Stainless Steel and uncoated Austenitic Stainless Steel has been conducted. The comparison studies are carried out and it is found that the coated Tungsten carbide (WC) over Austenitic Stainless Steel (SS316) gives longer life in corrosion environment and better resistance in erosion of surface materials in the exposure of high velocity air mixed with Al2O3 abrasive particles. Scanning Electron Microscope images analysis gives better improvement in surface behaviour of coated material when compared to uncoated material.

A product design and development process has been adopted to study and improve the performance of unit cleaner system. A hair trimmer with liquid detergent in cartridge is fixed as a cleaner system to design and analyse. The 3D model of the system is designed with NX CAD software. The modification is cartridge unit is made on counter face to increase the turbulence of the fluid in the wash zone. The file has been extracted and imported in LS Dyna for meshing the model for detergent liquid flow analysis. The velocity vector and pressure magnitude of the fluid flow is analysed through a StarCCM+ higher fluid analysis software. The input process condition of the pump in cartridge assemble unit has a speed 2000 rpm and velocity of the liquid as 1 m/s. From the analysis, the suction pressure noticed at the pump zone is 950 Pa and the discharge of fluid in the pump is 850 – 900 Pa at wash zone. Difference in fluid velocity found decreased and it is in the range of 0.8 to 0.95 m/s. The predominant factor in the design is alternate openings in case baffle has increased the turbulence in pressure and the velocity of the fluid found same.

Silicone rubber is a promising insulating material that has been performing well for different insulating and dielectric applications. However, in outdoor applications, environmental stresses cause structural and surface degradations that diminish its insulating properties. This effect of degradation can be reduced with the addition of a suitable filler to the polymer chains. For the investigation of structural changes and hydrophobicity four different systems were fabricated, including neat silicone rubber, a micro composite (with 15% micro-silica filler), and nanocomposites (with 2.5% and 5% nanosilica filler) by subjecting them to various hydrothermal conditions. In general, remarkable results were obtained by the addition of fillers. However, nanocomposites showed the best resistance against the applied stresses. In comparison to neat silicone rubber, the stability of the structure and hydrophobic behavior was better for micro-silica, which was further enhanced in the case of nanocomposites. The inclusion of 5% nanosilica showed the best results before and after applying aging conditions.

This investigation reports the effect of magnetic field during coating on the mechanical properties of the electroless Ni–P deposits. Magnetic field strength has been varied between 0 and 3A. The heat treatment was found to be more responsive for the sintering temperature between 300 and 400 °C. Micro hardness of the electroless Ni–P deposits was measured with a diamond indenter. Magnetic method produced more hardness (above 1250 VHN) than the conventional method (below 1000 VHN). The amorphous phase to crystalline transformation happens at this range of sintering. The pin-on-disc wear tester was used to measure the wear resistance of the deposits. The coated sample has a maximum weight loss of 0.077 mg at the end of the wear test (after 35 min) and 0.052 mg for magnetic field sintered sample at the same condition. Subsequently, with respect to increase in sintering temperature, the weight loss found decreased from 0.077 to 0.051 mg for as coat to 350 °C, respectively. It is also noticed that, the specific wear rate is 0.062 (kg/Nm3) for magnetic field sintered sample and 0.119 (kg/Nm3) for conventional sample. The characteristics of deposits produced in presence of magnetic field were found to be superior from those produced using conventional deposition techniques. Magnetic field has doubled the performance than the conventional techniques. Enhancements in properties were correlated with modified crystallinity and the conversion of Ni–P in to possible phosphides in the presence of magnetic field.

The recent research in biocompatible materials has been useful in replacing and supporting the fractured natural human bones/joints. Under some condition, negative reaction like release of ions from the bare metal toward the human body fluid leads to corrosion. In this proposed research paper, the biocompatibility of the laser surface-modified austenitic stainless steel (SS316L) and nickel-based superalloy (Inconel 718) was studied. The investigation on laser-modified surfaces is evaluated through electrochemical polarization analysis using simulated body fluid (SBF). The samples subjected to electrochemical polarization analysis were characterized by optical image analysis, SEM, EDS, and XRD analysis. It was inferred that laser surface-modified materials provided enhanced corrosion resistance and bare nickel alloy is more susceptible to corrosion by SBF.

Surface texturing by micro dimple formation is adopted in many applications to improve the tribological properties of materials. This work investigates dimple formation in titanium (TiAlSiZr) alloy using micro-electrical discharge machining (μ-EDM). Circular dimples were formed by varying the EDM parameters, that is, the capacitance (1000 and 10,000 pF), pulse-on time (100, 150, and 200 μs), and voltage (180, 200, and 220 V). The output responses such as burr height, burr width, and aspect ratio of the dimples were analyzed. The experimental results show that an ideal output response is obtained by simultaneously using a lower capacitance and a higher pulse-on time and voltage. The reason is the influence of these parameters on the spark energy and material removal rate, which determine the micro dimple geometry. Regression analysis was performed to predict the values, and the developed model showed goodness of fit. Further, desirability analysis was used to predict the optimal conditions (a capacitance of 1000 pF, pulse-on time of 178 μs, and voltage of 220 V), and the results were validated using confirmation experiments. The results were found to be in good agreement at the 95% confidence and prediction levels. Micrographs of the dimples and the three-dimensional micro dimple geometry were also analyzed.

Additive manufacturing and its process involved during manufacturing of engineering components are thriving areas in current researches. The usage of Direct Metal Laser Sintering (DMLS) process, can resolve the difficulties involved in the manufacturing of components used with turbine engines. The commercially available alloy Incone1718 is compatible with DMLS based Su-718 material. This investigation examines and experiments the effect of heat treatment process, using a combination of solutionizing at 1100 °C (2h) and aging at 845 °C for 24h, followed by air cooling. The metallurgical changes were observed with the help of optical imaging, to perceive the phase/structural transformation. Further, the heat treated samples were subjected to electrochemical polarization studies with 1.0 M H2SO4 as an electrolyte. The influence of alloying elements, before and after the heat treatment process of samples were analysed through scanning electron microscope and energy dispersive spectroscopy. The experimental results prove that, corrosion resistance was found to be much better while following the sequence of DMLS HT > Bare DMLS > Bare Commercial > Commercial HT alloy. However, the heat treated DMLS sample obtained during experimentation had lower current density and more positive corrosion potential than the commercial alloys.

Development on austenitic stainless steel and nickel-based superalloys have played vital role in the field of manufacturing of engineering components. The selection of materials depends upon working environment and operating conditions. In some cases, the combination of two different materials is used to join and apply them for specific working conditions. Joining of stainless and super alloys for turbine power shaft and high temperature steam pipe lines are the two major examples of this. Challenges in current research are to join dissimilar materials without disturbing the properties of parent metals. Materials joining process either may be at fusion state or solid state. Extensive research articles are available to discuss about the joining process of similar materials. While considering the dissimilar materials, individual conditions has to be satisfied depending upon the choice of joining process. Sample thickness, weld energy required, filler material, weld speed, weld design, etc. are the pre-requisite for completion of the process. The weld zone heat transformation (thermal gradient) thickness and its metallurgical quality are the major outcome in welding process. In this chapter, the research is focused on joining of two different metals using laser and electron beam welding (EBW) process. The metallurgical changes in the weld zone are studied. Further, the electrochemical behaviour of austenitic stainless steel and nickel-based superalloy dissimilar weld has been studied using 3.5% NaCl solution. The samples exposed to corrosion medium are followed with metallurgical characterization techniques such as: Optical imaging, SEM, EDS and XRD. Results from the investigation indicate that the EBW sample is superior than laser beam welded sample. The heat convention under laser welding has induced the samples to metallurgical deficiency.

Challenge has been taken to develop nickel – based superalloy SU718 through additive manufacturing process. The novelty of this research is to develop the SU718 alloy through direct metal laser sintering (DMLS) process for investigation. In this technique, powder bed is exposed to the laser energy to sinter and build the formation of alloy. Thus, formed alloys are not in isentropic structure and vary with dendrite morphology. In order to explore the behavior of alloying elements and to concurrently increase the mechanical properties, as-built alloys were heat-treated at different combinations with a plan of solutionizing, annealing and aging process. The dendritic structure from the as-built alloy was diffused through the HT plan to form austenitic structures. The mechanical properties and metallurgical qualities of the alloy were examined through different standard heat treatment (HT) cycles. The strengthening phase of γ’ and γ” was found to be increased after the solutionizing heat treatment process with a small amount of improvement in the δ phase. The mechanical properties of the as-built and HT SU718 alloys were evaluated. The evaluation results show the improvement in tensile strength and bulk hardness with less impact strength. Also, elongation of alloy was observed to be slightly higher in solutionizing than homogenization treatment.

In this paper, the sliding wear behaviour of nickel based superalloy pin was investigated on disc with two different coatings. The plasma sprayed NiCr–Cr2O3 coating and Al2O3+40%TiO2 (A40T) coating were used on the disc for wear studies. The sliding wear tests were performed on dry conditions at room temperature for a constant sliding velocity for two different applied loads (5 and 10 N). The mass loss, wear resistance and coefficient of friction between the pin and disc were studied during investigations. The wear mechanism involved in the NiCr–Cr2O3 coatings is three-body abrasion and Cr2O3 being the third body between pin and disc. The wear rate is high due to the applied load and suppressed cracks. In A40T coating, the minute debris collected on the surface of the coatings acts as a solid lubricant and reduces friction and wear rate. The SEM and energy dispersive spectroscopy analysis were also carried out for characterisation studies on pin after wear studies. The life of nickel pin on A40T coatings ...

The filler materials are reinforced along with natural fibers in the composite to improve the quality and property of the component materials based on the requirements and its applications. In this paper, hybrid natural fiber composites were developed with and without filler materials as reinforcement. The developed hybrid natural fiber composites are machined using abrasive water jet cutting process with three different cutting parameters. The influences of cutting parameters are evaluated with respect to the kerf wall inclination, material removal rate, and surface roughness. The surface morphology was also studied to infer the basic mechanism involved during composite machining. The hybrid fiber composite with filler has proved that it can produce good engineering component without delamination and fiber pullouts during machining.

The plasma-sprayed NiCr–Cr2O3 and Al2O3–40 % TiO2 powders are deposited as coating on nickel-based superalloy. The electrochemical polarisation studies were carried out with 1.0 M H2SO4 solution as a corrosive medium. The corrosion current density of the coated sample was found to be decreased and exhibits better corrosion resistance than bare metal. The characterisation studies on the exposed sample result reveal that the bare metal has undergone severe intergranular attack and segregation on austenitic phase. The corrosion products formed are in the form of sulphides, and contribution of sulphur was noticed through EDS analysis.

Nickel based superalloys are difficult to manufacture in conventional production process. Laser based fusion bed method is adopted to develop metal. Direct metal laser sintering (DMLS) is one of the best to produce difficult to produce metal component. The developed alloy was planned to perform heat treatment process and the metallurgical properties are enriched. To investigate initial effects of microstructure, the material as deposit and treated material under are studied in detail. To compare the result of DMLS and commercial alloy were also heat treated at same condition. In this research, corrosion behavior of DMLS alloy and commercially available Inconel 718 are tested with 1.0 M H2SO4 solution at room temperature. The electrochemical results of DMLS and commercial alloy are compared for corrosion rate. It was found that the DMLS sample give good corrosion resistance than the commercial IN718 alloy due to the precipitation γ” is high. The segregation of iron element is more in commercial alloy and nickel element is high in DMLS alloy was found in the EDS analysis.

This paper reports some results of experimental investigation conducted on abrasive water jet machining (AWJM) of medium carbon low alloy (EN24) steel. EN24 steel samples of different thickness have been machined at various combinations of AWJM parameters. Three important AWJM parameters namely water jet pressure, nozzle traverse speed, and stand-off distance have been varied at three levels each. Three important responses i.e. material removal rate, kerf wall inclination, and surface roughness (average roughness) have been considered as the machinability indicators. The variation of these machinability indicators with a range of thicknesses of EN24 steel samples has been investigated. It is found that AWJM is capable to machine EN24 steel at very high MRR even at the increased thickness. But, surface finish deterioration is prominent with sample having higher thickness. Moreover, nozzle traverse speed is identified as the most significant parameter. It is concluded that the jet pressure of 240MPa with traverse speed of 20mm/min can produce good machinability for AWJM of EN24 Steel.

The Inconel 617 with plasma sprayed Al2O3–40%TiO2 (A40T) and NiCr–Cr2O3 coatings were investigated for the hot corrosion behaviour at 1000°C for gas turbine applications. The behaviour of the alloy under the mixed salt environment with and without V2O5 in Na2SO4 and NaCl was analysed by means of mass change per unit area, optical and SEM images along with X-ray diffraction and EDAX. Microstructural and EDAX analyses revealed presence of oxides, rich in Ni and Mo on the surface of the samples. The coated sample exhibited better corrosion resistance in A40T and NiCr – Cr2O3 coatings than bare alloy.

In this paper, two different evolutionary algorithm-based neural network models were developed to optimise the unit production cost. The hybrid neural network models are, namely, genetic algorithm-based neural network (GA-NN) model and particle swarm optimization- based neural network (PSO-NN) model. These hybrid neural network models were used to find the optimal cutting conditions of Ti(C,N) mixed alumina-based ceramic cutting tool (CC650) and SiC whisker-reinforced alumina- based ceramic cutting tool (CC670) on machining glass fibre-reinforced plastic (GFRP) composite. The objective considered was the minimization of unit production cost subjected to various machine constraints. An orthogonal design and analysis of variance was employed to determine the effective cutting parameters on the tool life. Neural network helps obtain a fairly accurate prediction, even when enough and adequate information is not available. The GA-NN and PSO-NN models were compared for their performance. Optimal cutting conditions obtained with the PSO-NN model are the best possible compromise com- pared with the GA-NN model during machining GFRP composite using alumina cutting tool. This model also proved that neural networks are capable of reducing uncertainties related to the optimization and estimation of unit production cost.

The development on composite materials has a tremendous role in the place of metals and alloys for different engineering applications. On the other hand, the material selected for specific applications are prone to fail in bulk with surface defect and shear based on working conditions. Hence, the challenges convince the researchers to modifying the materials with different reinforcement. In this paper, glass fibre composite material was developed with and without fillers to investigate on solid particle erosion test rig. From the experiments, the surface wear and parameter influencing air jet erosion are studied in detail. The parameters involve are jet pressure, volume of erodent and exposed time at constant angle of impingement. Based on mass change erosive wear rate are empirically calculated. The surface topography of the sample are observed with electron microscopic analysis for superficial studies. Influence of process parameter is evaluated using 2k factorial design. It is confirmed that erodent behaviour and composite with filler material are dominating the erosive wear rate. The sample with polyester resin has an affinity to hold the abrasive particle as inclusion during striking of solid particle. Therefore the proposed model with natural filler in fibre reinforced surface has resistance toward erosion.

Composite is one of the predominant material for most challenging engineering components. Most of the components are in the place of automobile structure, aircraft structures, and wind turbine blade and so on. At the same all the components are indulged to mechanical loading. Recent research on composite material are machinability, wear, tear and corrosion studies. One of the major issue on recent research was solid particle air jet erosion. In this paper hybrid composite material with and without filler. The fibre are in the combination of hemp – kevlar (60:40 wt.%) as reinforcement using epoxy as a matrix. The natural material palm and coconut shell are used as filler materials in the form of crushed powder. The process parameter involved are air jet velocity, volume of erodent and angle of impingement. Experiment performed are in eight different combinations followed from 2k (k = 3) factorial design. From the investigation surface morphology was studied using electron microscope. Mass change with respect to time are used to calculate wear rate and the influence of the process parameters. While solid particle erosion the hard particle impregnates in soft matrix material. Influence of filler material has reduced the wear and compared to plain natural composite material.

Alumina-based ceramic cutting tools can be operated at higher cutting speeds than carbide and cermet tools. This results in increased metal removal rates and productivity. While the initial cost of alumina based ceramic inserts is generally higher than carbide or cermet inserts, the cost per part machined is often lower. Production cost is the main concern of the industry and it has to be optimised to fully utilize the advantages of ceramic cutting tools. In this study, optimization of machining parameters on machining S.G. iron (ASTM A536 60-40-18) using alumina based ceramic cutting tools is presented. Before doing the optimization work, experimental machining study is carried out using Ti [C,N] mixed alumina ceramic cutting tool (CC 650) and Zirconia toughened alumina ceramic cutting tool (Widialox G) to get actual input values to the optimization problem, so that the optimized results will be realistic. The optimum machining parameters are found out using Genetic algorithm and it is found that Widialo...

Traffic congestion is a growing problem in urban areas nowadays. In this paper, a system is developed to control and monitor the congestion of traffic. The main motivation is to detect the presence and absence of vehicles on the road using statistical approach integrated with conventional image processing techniques. For this purpose, we have develop a “Probability Based Vehicle Detection (PBVD)” algorithm based Vehicle Detection System (VDS) integrated with post - processing subsystems to form a complete traffic control system. The system has the capability to obtain vehicle statistics during controlling traffic. Simulations are performed by developing complete prototype traffic architecture. Comparison is done using the result acquired from prototype system and processing a real time video of traffic scene. Simulation results show the effectiveness of the proposed scheme.

Annealing after hot rolling or extrusion produces anisotropic shape changes in 18 pct Ni maraging steel. It has been observed that the material contracts along the longitudinal direction but expands perpendicular to it. This peculiar behavior has been studied in situ by means of a dilatometer. The dimensional anisotropy (DA) was found to decrease with an increase in the annealing temperature. The metallographic investigations have led to the conclusion that DA is related to the presence of banding in the material.

Fatigue failure in the central main bearing (CMB) of the compressor shaft of an aero-engine resulted in an air-crash. The cage of the CMB broke due to fatigue, got stuck between the bearing balls and the outer race, misaligned them resulting in severe wear of the components and damaged the function of the engine. Simulated laboratory tests are conducted and the source of cyclic stresses is discussed.

Titanium nitride coatings have been deposited using cathodic arc physical vapor deposition technique on the commercially available steels. Effect of nitrogen partial pressure was studied keeping bias voltage, arc current and deposition time constant. Phases formed during coating were identified by x-ray diffraction. Microhardness was also determined using Vickers microhardness tester. The study revealed that only Ti2N was formed as a function of nitrogen partial pressure. The enhancement in hardness was found to be dependent on substrate material. The deposited coatings exhibited variation in colors (from light golden yellow to greenish golden yellow) which were attributed to the nitrogen partial pressure and the substrate material.

Samples of 18%Ni 350 grade maraging steel were repeatedly thermal-cycled between ambient temperature and 800°C (above the austenizing finish temperature, A f ). This heat treatment produced retained austenite in the microstructure, the volume fraction of which increased and decreased alternatively in relation to the number of thermal cycles. It was observed that the retained austenite (γ), after having grown to a certain extent transformed back to the martensite phase (α 2 ) and had the following orientation relationship with the parent martensite matrix (α 1 ): (110) α1 //(110) α2 (112) α1 //(110) α2 . This may be explained on the basis of the Nishiyama-Wassermann (N-W) and Kudjumov-Sachs (K-S) orientation relationships between austenite (γ) and martensite (α) phases.

Austenite reversion was studied in 18% Ni 350 grade maraging steel. The samples were heat treated from room temperature to the austenite phase field and, without holding, they were cooled again to ambient temperature. The reverted austenite which was retained after this heat treatment was examined using a scanning transmission electron microscope equipped with an energy dispersive spectroscopic system. Two morphologies of the austenite were observed. The first forms at the martensite lath boundaries and the other nucleates inside the martensite laths in the form of Widmanstatten plates. These Widmanstatten plates mostly appear as coupled twins. The coupled twins have a distinct midrib which was found parallel to (1 1 1)γ and (1 1 0)α planes. The latter morphology of austenite appeared only after the formation of Ni3Ti precipitates. Growth of Fe2Mo precipitates was not observed in this heat-treatment cycle. Both Nishyama–Wassermann and Kurdjumo–Sachs orientation relationships were found between the austenite and martensite phases. On the basis of these results, it can be suggested that intra-lath-reverted austenite is formed on or by the local dissolution of Ni3Ti precipitates. © 1998 Kluwer Academic Publishers

Austenite and martensite textures were studied in 18 pct Ni 350-maraging steel as a function of various degrees of cold rolling. The austenite phase in the samples was produced by repeated thermal cycling between ambient and 800 °C. The austenite phase thus formed was mechanically unstable and transformed to the martensite phase after 30 pct cold rolling. The texture developed as a result of cold rolling, and its effect upon microstructure and hardness has been studied.

The cause of the fatigue failure in the retaining ring of the compressor region of an aero-engine turbine was found to be the presence of a high concentration of nonmetallic inclusions. The results of chemical analysis were used to estimate the phases present. The most frequently observed inclusions were spinel solid solutions of the type MO · N2O3, where M=Fe, Mn, or Mg and N=Cr or Al. The detrimental inclusions were corundum, calcium aluminates, cristobalite, and silicates. The most detrimental phases were traced on the surfaces of the specimens fractured using impact loading; the comparison is being made with the polished surfaces and the tensile specimen fracture surfaces. The inclusions in the failed retaining ring were compared with the ones in a similar component obtained from a used engine. In the case of the latter, a large number of fine and elongated (Mn, Cr, Fe)S inclusions were present along with spinels. The nondeformable, rigid oxide particles are considered more undesirable than the sulfides as far as fatigue life of the component is concerned. It has been reported that the presence of sulfides may eliminate the stresses due to oxides.

Chemical inhomogeneity results in the formation of banded structure in high-strength maraging steels. Segregation of titanium and molybdenum was found to be the primary cause of banded structure formation. When the concentrations of these elements increased beyond certain critical levels, bands comprising different grain sizes formed. The inclusions existed preferentially along the interface of the bands. A high-temperature homogenization treatment substantially reduced or eliminated the banded structure. The large grain size resulting from the homogenization treatment was subsequently reduced by a grain refinement treatment. The mechanical properties of the steel substantially improved following homogenization and grain refinement.

Wear-resistant, hard surfaces of high-speed tool steel were synthesized on mild steel specimens. Discs of mild steel were subjected to carburization to a depth of 2.5 mm. Thin strips of tungsten were spot welded and the specimen was subjected to electron beam surface melting. The beam power was varied from 60 kV, 10 mA to 60 kV, 20 mA. Oscillation frequency and the specimen translation velocity were kept at 1000 Hz and 2 cm s-1, respectively. The width of the modified layer was 10 mm while the depth varied from 0.7–2.3 mm. A concentration of up to 30 wt% tungsten could be achieved in the surface layer by varying the thickness of the foil spot welded prior to electron-beam melting. Tungsten concentration was uniform along the depth. The hardness achieved in the as-solidified layer was uniform along the depth and reached 800 Hv. The reprocessing of the alloyed layer with the beam promoted fine carbide precipitation which then resulted in refinement of martensite plates.

This paper examines the causes of the catastrophic failure of a gas-turbine aero engine which led to an air crash. The failure was traced to the fatigue failure of a 1.5 mm diameter retaining ring made from AISI 304 stainless steel.

Changes in the lattice parameter of martensite phase in a maraging steel is measured as a function of ageing temperatures. A decrease in the lattice parameter is observed when aged between 400–650°C which is attributed to the depletion of alloying elements in the martensite matrix as a consequence of precipitation and austenite formation. An increase in the lattice from 650 to 710°C was characteristic of enrichment of alloying elements in the martensite matrix due to dissolution of austenite phase. A minimum value of the lattice parameter of martensite is observed at 650 °C which coincides with the maximum vol % of retained austenite. Electrical resistivity, hardness measurements, andin situ high temperature dilatometry was also carried out to delineate various precipitation reactions that occur in this steel.[/p]

When aluminium alloys are exposed to different chemical environment at high temperature, corrosion is a life-limiting factor. In this investigation, nano composites of double layer CSZ and SiAlON thermal barrier coating were deposited on the aluminium alloy substrate using atmospheric plasma spraying technique. The anti-corrosion behaviour of the CSZ and SiAlON double layer coating as well as substrate were investigated in 3.5% NaCl solution and H2SO4 solution by potentiodynamic polarisation method. The results reveal that the coated sample shows highest corrosion resistant than the bare metal. To understand the degree of corrosion behaviour in coating, SEM analysis is carried out. On the other hand, the structural integrity and hardness of the surface of coatings were investigated by using scratch test. The scratched surfaces were inspected by SEM and phase analysis was carried by EDX and the results were characterised. The scratch test shows a better hardness resistance even at high load.

The texture incorporated during cold rolling of maraging steel persists even when the samples are annealed at temperatures close to the melting point. The texture influences the microstructural developments observed following aging, which in turn affects the magnetic properties of maraging steel. The maximum coercive field, observed after aging at about 700°C, increased from about 11 140 A m−1 in the as rolled and aged condition to about 14 720 A m−1 in the specimen annealed at 1000°C before aging. The corresponding saturation magnetisation values also increased from about 1·040 to about 1·300 T. The prior annealing affects the morphology of the precipitates as well as the reverted austenite.MST/3129

Austenitic alloys have been produced by additional alloying in maraging steel grade 18 Ni at 2400 MPa. The concentration of Mo, Ni and Co was increased individually until the martensite start temperature Ms, was suppressed below ambient value. Charpy impact strength, tensile strength and magnetic properties were determined. The impact strength in the annealed condition ranged between 260 to 294 J. In alloys where martensitic transformation occurred following quenching in liquid nitrogen, the impact strength dropped appreciably and was found to be in the range 120–216 J. The tensile strengths of the austenite and martensite phases ranged between 680 to 890 and 1030 to 1100 MPa, respectively. It was observed that the austenite phase transformed to martensite in the region that under went plastic deformation during Charpy and tensile testing. The degree of transformation incorporated, varied as a function of composition. The magnetic properties of the austenite phases were typical of a very weak magnetic material. The coercive field and saturation magnetization values were in the range 1034–2387 Am−1 and 1.6–2.9 T, respectively. In contrast to the general observation, the austenite phase containing high Co exhibited ferromagnetic behaviour. The coercive field and saturation magnetization of ferromagnetic austenite was 1034 Am−1 and 11 T, respectively.

The possibility of gainfully utilizing grade 18Ni(350) maraging steel scrap has been investigated, along with the effect of additional alloying with niobium. A vacuum induction melting and casting furnace was used for melting and additional alloying. The cast ingots were hot forged and their properties compared with those of the stock material. The composition of the reprocessed material was found to be within the prescribed range for 18Ni(350) steel, except for some loss in titanium content. The hardness and tensile strength of the recycled steel were similar to those of the stock material. A slight decrease in hardness in the aged condition could be attributed to loss of titanium during remelting. Charpy V- notch impact test-ing indicated significantly higher toughness in the remelted material; this has been attributed to a homo-geneous, refined microstructure and a lower level of inclusions. Additional alloying with 2% Nb not only improved the mechanical properties but also affected the amount of reverted austenite obtained after ag-ing.