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Laser-induced forward transfer (LIFT) is a non-lithography, nozzle-free printing technique widely used to transfer different materials with high resolutions. It can deposit functional material without phase change to fabricate actuators, transducers, and other MEMS devices. In this work, LIFT is deployed to deposit NiTi shape memory alloy using CO2 laser (λ = 10.6 µm) in the form of the solid phase. The silicon wafer is used as the donor substrate since it is transparent to the CO2 laser wavelength, while the silica glass is used as an acceptor substrate. The donor substrate is coated with the Polydimethylsiloxane (PDMS) as a sacrificial layer that absorbs the laser energy and induces a thrust force for the transfer mechanism. Over the sacrificial layer, NiTi Shape memory alloy thin film is deposited with DC sputtering technique at working pressure 2 × 10–3 mbar and standoff distance 5 cm. After the donor preparation, the LIFT is deployed at various laser fluences and SOD to transfer NiTi on the silica glass substrate. The deposited geometry’s surface morphology has beenanalyzed using a scanning electron microscope (SEM) and optical microscope. The functionality of the deposited materials has been analyzed using Differential Scanning Calorimetry (DSC).

Glass material has sophisticated mechanical and physical properties and is widely used in various industrial fields such as optics, biomedical and electronics. However, due to its brittle nature, glass is hard to process material. In order to produce a part with a good surface quality, glass is processed in liquid or viscous state. Conventional machining results in poor surface quality and sometime fracture of the part. This paper investigates applicability of micro milling method in processing glass material. The effect of cutting parameters, such as cutting speed, feedrate and depth of cut, on generated surface quality is evaluated via surface examination under optical microscope. Experimental results showed that selection of right cutting parameters is extremely important, and it has direct effect on cutting mechanism and generated surface quality.

The present work investigated, the effect of heat treatment on tribological behaviour of 0.6% C steel. Samples were austenitized at 910 ℃ for 1 h in a muffle furnace and then cooling was done at different cooling rate, like furnace cooling (annealing) and air cooling (normalizing). Followed by microstructural characterization was carried out using optical microscopy and XRD analysis. Vickers hardness tester was used to evaluate hardness of the samples. Wear behavior of the as-received and heat treated samples were evaluated by pin on disc wear tester. The microstructure showed that presence of predominantly pearlite grains and less ferrite grains in as received and heat treated sample. Phase analysis showed the ferrite and carbide phase in as received and heat treated sample. Micro-hardness value decreased from 548 HV for as received 0.6% C steel to 256 HV for annealed sample and 412 HV for normalized sample. The more wear resistance of as received sample as compared to annealed and normalized sample. The wear depth was 20 µm for as received, on the other hand, 390 µm for normalized sample and 410 µm for annealed sample. The coefficient of friction of as received sample varies from 0.052 to 0.062, on the other hand, coefficient of friction varies from 0.052 to 0.062 for normalized sample and 0.062 to 0.073 for annealed sample.

The objective of the present work is to investigate the microstructure evolution in Fe-12 Mn-13 Al-4.8 Ni-0.8 C wt.% steel after two-phase heat treatment, followed by different cooling regimes. The alloy was homogenized at 1200 ℃ for 3 h followed by forging and water quenching to room temperature. Thereafter it was heat-treated in a two-phase region and cooled to room temperature through different cooling modes viz. water quenching (WQ), air cooling (AC) and furnace cooling (FC). The microstructure of the heat-treated and cooled samples was investigated through optical microscopy, scanning electron microscope (SEM), energy dispersive spectrometry (EDS), X-ray diffractometry (XRD) and electron back-scattered diffraction (EBSD). The WQ sample was found to have a duplex microstructure consisting primarily of δ-ferrite and austenite, however, a minor α-ferrite (fine grain) phase was also detected inside austenite. In the AC sample, a small amount of α-ferrite and intragranular k-carbide was formed, along with δ-ferrite and austenite as the major phases. The α-ferrite formed within austenite in the WQ and AC samples was found to nucleate and grow at austenite twin boundaries and triple junctions. While in the FC sample, a significant amount of α-ferrite and k-carbide was found to form due to the decomposition of austenite. Interestingly two types of k-carbide viz. modulated intragranular type and lamellar type were found to form in the FC sample.

Using the Raman spectroscopic analysis system that gives the chemical information of the biomaterials, classification is performed through the acquisition of fingerprint signals for each cell line, and the basis of the diagnosis is provided. The origin of diagnosis can be clarified by precise analysis through comparison of local signals and morphology in cells, including measurement at tissue level. In this result, normal breast cell line (MCF-10A) and breast cancer cell lines (MDA-MB-231, MDA-MB-453) were characterized using Raman spectroscopy, atomic force microscopy (AFM), and optical microscopy. These three modalities were combined in order to not only separate cancerous and noncancerous cell lines but to analyze their morphological and optical properties. From the results, the inherent optical properties of cancer cells separated from normal cells in terms of local variation were observed. Bright-field (BF) transmission imaging is also compared to the morphological height difference obtained from AFM and is correlated with surface Raman spectra.

Aluminium alloys are mostly used in marine, defence, aerospace, automobile industrial sectors, etc. which are increasing at all times due to their good corrosion resistance and high strength compared to weight ratio. In this research work, the corrosion behaviour of plasma melted LM6 alloy was carried out. For the study of the corrosion behaviour, the prepared alloy is held on seawater for 6 weeks, and weight loss/gain in each week was measured. The corrosion mechanism is prominent by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and optical microscope. The microstructure shows that on the surface, isolated pits are formed and the number and size of pits are increased continuously with increasing number week reveal to seawater. The highest hardness value of 81.12 VHN is seen in 3rd week corroded sample. Hardness is found to be the lowest in non-corroded samples, and it increases up to 3rd week reveal in seawater and then decreases due to corrosion phenomena. The main reason is clear to obtain from the XRD, EDX and SEM analysis. The most predominant corrosion mechanism is seen to be pitting corrosion phenomena from the experiment.

This project involves the use of friction stir processing with a change in the number of passes on grain refinement of pure copper. FSP is a rising metal processing technique for manufacturing fine-grained structures. The project’s main goal was to determine the outcome of change in the number of passes and pass direction on the grain size and microstructure. The change in microstructure is accompanied by changes in properties like grain structure, tensile strength, and hardness. FSP has been done on 3-mm-thick pure copper plates, using a tungsten carbide tool of 18 mm diameter shoulder with a tapered pin of diameter 3 mm, a tool rotation speed of 1500 rpm, 2° tilt angle and tool traverse speed of 20 mm/min with the variable being the number of passes and pass direction. The optical microscopy, grain size measurements of the nugget region, and time–temperature plot is presented. The specimen with smaller grain sizes are further tested for tensile strength.

Visible light can interact efficiently with the vibronic and electronic systems of a sample and fetch rich information about the intrinsic features, such as the chemical, physical and biological properties of the sample. Optical techniques have therefore been convenient tools for a long time to analyze and image various materials. However, the spatial resolution in optical microscopy is restricted by the diffraction limit of light, making it impossible to study samples much smaller than the wavelength of the probing light. This restriction can be overcome if a conventional optical microscopy, such as Raman microscopy, is combined with near-field techniques. Tip-enhanced Raman spectroscopy (TERS) is such a technique. It utilizes a sharp metallic nano-tip to intensely enhance and strongly confine light within a tiny volume near the tip-apex and enables characterization of samples at the nanoscale. In this Chapter, we discuss the details of this technique and explain how light can be tightly confined into a nanometric volume for true nanoscale exploration of samples. TERS is still a young technique and has been going through a rapid development in the past two decades, which has not only made it more reliable and sturdier over the period, but has also brought this apparently complicated technique out from the laboratories of the veterans to the market for researchers who are experts in different fields. This has obviously happened with improved adaptability, flexibility and robustness with possibilities of a wide range of applications. We will discuss some interesting applications and related instrumentations for TERS.

Attempt has been taken towards carrying out detailed investigation about the relevance of using fabricated crystalline silica-aluminium metal-based hybrid composite as biomedical implants, in vitro. In vitro corrosion study has carried out into simulated body fluid (SBF), and corresponding changes of surface morphology have found out and reported. In addition, bactericidal analysis and cytotoxicity study have carried out and reported for the same fabricated metal matrix composites as per available standards.

This work aims to investigate the performance of different cobalt-based coatings such as Stellite 6 (St6), WC-Co (W1) and Stellite 21 (St21) on the different grades of boiler steel. The different grades of boiler steel chosen for this purpose are SAE213-T91(BS1), SAE213-T12 (BS2) and SAE 208 (BS3). Coating powders were deposited on the selected substrate materials under different impact angles (30o and 90o) using the detonation gun spray method. The properties of the coatings were assessed using an optical microscope, microhardness tester and surface roughness tester. In addition, an erosion and oxidation study of the coating was also carried out for quality check of the coatings. The erosion test was performed at room temperature as well as an elevated temperature of 400 oC. The cyclic oxidation of different coated samples was carried out in air at 900 oC for 50 cycles of 1 h duration. The result shows that at room temperature, the erosion resistance of W1 coated boiler steel substrate is higher than that of steel substrate coated with St6 and St21 powder. But, at an elevated temperature of 400 oC, their resistance to erosion resistance decreases significantly which may be due to the phase softening. St6 and St21 coatings are found to be successful in lowering the oxidation rate of SAE 213-T91 boiler steel. This may happen due to the formation of a protective Cr2O3 phase along with CoCr2O4 phase in the oxide scale.

Renewable resources of lubricant are dominating the metalworking industry applications since chemical modification of vegetable-based oil enhanced the tribological properties of the bio-based lubricant. Nevertheless, refinement of lubricant on physiochemical quality is insufficient to inhibit friction and wear, thus additives are acquired to enhance the based-oil features. This study was aimed to evaluate the surface morphology properties induced by the friction from tribology test of modified RBD palm oil (MRPO) mixed with bamboo activated carbon (ACB) as an additive. In this work, the concentration of bamboo activated carbon is varied at 0.05 and 0.1 wt%. Four ball test was conducted to measure the tribological characteristics of lubricant samples. The steel/steel contact surfaces were analyzed using several type of analytical techniques; optical microscope, and profilometer. Results appointed that MRPO have good surface protection due to the chemical modification of triesters. However, MRPO + 0.05% ACB shown better improvement on wear and friction, due to bonding of triester with proper ratio of additives. Tribology analysis revealed that steel/steel contacts cause worst worn scars and frictional force on MRPO + 0.1% ACB. Surface morphology analyses described an excellent performance of MRPO and MRPO + 0.05% ACB. Predominantly, MRPO with mass concentration of 0.05 wt% ACB contributed to the improvement of morphology structure of sliding contact surfaces which complementary to sustainable lubrication.

The present study compares the weld performance of the two variants of activated tungsten inert gas welding (A-TIG) process known as, Flux Bonded TIG (FB-TIG) process and Flux Zone TIG (FZ-TIG) process on modified 9Cr–1Mo (P91) Steel. Bead-on-plate welding samples were prepared using TiO2 flux with FB-TIG and TiO2 and ZnO flux combination was used in FZ-TIG process. For systematic comparison, bead-on-plate welding samples were also prepared for A-TIG and conventional, i.e. Normal TIG (N-TIG) process with the same set of process parameters. Metallurgical characterization of all the bead-on-plate weld samples was conducted using optical microscopy, and comparison of weld dimensions was made amongst all the weld samples, prepared understudy. Experimental results showed that the FZ-TIG variant had offered the highest depth of penetration (Dp) and least bead width (Bw) and highest depth-to-width (Dw) ratio, compared to the rest of the variants, which is desirable.

An experimental investigation was undertaken to develop a heat shield by depositing lanthanum phosphate (LaPO4) in powder form on AISI 316 grade stainless steel of six mm plate using plasma process in the presence of argon gas to create an inert environment. Lanthanum phosphate has high melting point and non-reactive towards metal surfaces having low thermal conductivity with superior corrosion resistance. These superior physical properties are imperative for the material for corrosion and temperature barrier applications. Cross-weaving technique was adopted in depositing the powder in metallic plate. Characterization of the coating thickness was done at different thickness of coating using plasma spray technology and adopting layer on layer and weaving methodology. Microstructure of the metal and homogeneity of the deposit was evaluated using an optical microscope. Phase of the metal deposition was investigated in X-ray diffraction instrument. The coating thickness and its interface were examined using optical microscope (OM). The coating thickness was also optimized using a buffer layer on the stainless steel plate. The LaPO4-coated stainless steel plate was subjected to heat on the uncoated side. Temperature of both coated and uncoated sides was measured to assess the heat retention using infrared thermography technique. A thermal differential in excess of 10% was observed between coated and uncoated side of the stainless steel plate.

Al-alloys are always used increasing in marine environments because of their better resistance, low density, good mechanical properties, excellent castability and fluidity. In this work, the study on the corrosion behaviour of LM6 alloy is prepared by the plasma melting method. Some of the alloy samples were heated at temperature 350 and 450 °C for 2 h then water quenched. All the alloy samples (both H.T and non-H.T) are exposed to seawater for 42 days, and then every 7 days measured the weight gain/loss. The microstructure, hardness and corrosion behaviour of the H.T and non-H.T corroded samples comparative study were carried out. The composition and morphology of corrosion products were examined with the help of an optical microscope, SEM and XRD. The results indicated that 450 °C H.T samples have lower corrosion rate values and higher hardness value than 350 °C H.T and non-H.T samples. Optical micrographs show that the size and number of isolated surface pits formed on H.T 450 °C alloy samples are less as compared to H.T at 350 °C and non-H.T alloy samples. 450 °C H.T samples exhibit more corrosion resistance than 350 °C H.T and non-H.T samples due to the heat treatment effect on the alloy samples. The pitting corrosion mechanism gets from the experimental investigation.

With the decrement of non-renewable resources, the researches of energy materials become more and more necessary and important. Many imaging methods have been employed to investigate the operation mechanism of energy materials. In this chapter, we would like to focus on the synchrotron-based transmission X-ray microscopy, due to its high resolution compared with optical microscopy and high penetration in contrast to electron microscopy. Moreover, the combination of transmission X-ray microscopy and X-ray absorption near-edge structure spectroscopy can provide element mapping. With the transmission X-ray microscopy, the morphology and element mapping of the energy materials can be obtained to explain many phenomena and reveal some mechanisms. To show the outstanding characterization capacity, we review parts of interesting and significant research works in the domain of battery materials here. On the basis of these researches, the future development of hardware and software of transmission X-ray microscopy is also discussed.

The purpose of this paper is to present the results of an investigation on the straightness achievable on three cavities: channel, square and cross-channel (square pillars). The steps included machining of cavities in series of three having a nominal dimension of 1000 µm on a steel sample using 200 µm tungsten carbide electrode in micro-electrical discharge-milling (µ-ED-milling). An Olympus optical microscope was utilized to examine the geometry of micro-cavities. The Least Square Method (LSM), which is commonly used in metrology for fitting reference elements, has been used. The LSM solutions for the primary set of data points obtained through Olympus Analysis Five software measurements were calculated to find the achievable straightness. It was found that straightness tolerance of square pillars (19.19 μm) is better than microchannels (31.33 μm) and far better than square geometries (50.66 μm).

In this study, a relatively new manufacturing process - friction stir welding (FSW) was used to join 3 mm thick AZ91D plates. The process was conducted at a traverse speed of 50 mm/min and rotational speed of 1000 rpm; and the weld sample’s microstructural and mechanical properties were evaluated. The microstructural analysis was conducted with an optical microscope. The mechanical properties evaluation includes tensile and microhardness tests. The microstructural analysis shows a defect-free sound joint of the materials with absence of voids and wormholes. The tensile strength of the weld was enhanced significantly and a joint efficiency of 109% was achieved. However, there was no substantial effect on the ductility and hardness properties of the weld sample. In conclusion, the FSW process is an efficient and sustainable technique to join and enhance the tensile properties of similar AZ91D alloys.

Heat input during welding is the controlling factor for weld bead geometry (bead width, reinforcement height, and depth of penetration). Heat input plays an important role to evaluate the quality of the joints. Present experimental investigation aims to determine the effect of heat input on weld bead geometry. Gas metal arc welding of creep strength enhanced ferritic (CSEF) steel P91 with filler wire ER90SB9 using pure argon gas has been done. It has been found out that with increasing heat input, depth of penetration increases. However, variation of bead width and reinforcement with heat input is not so much clear. Based on bead-on-plate experiment, heat input of 1.337 kJ/mm was recommended for joining of 6 mm thick P91 steel plate. For weldments characterization, optical macroscope, optical microscope, Vickers microhardness tester were used.

The present investigation reveals the preparation, microstructural characterization, and hardness evaluation of functionally graded aluminium alloy SiC particulate metal matrix composite. Metal matrix composite developed by liquid stir casting method accompanied by vertical centrifugal casting to produce 240 mm outer diameter and 28 mm thick A356-20 wt.% SiCp functionally graded metal matrix composite (FGMMC) ring. 2 wt.% of magnesium is added for improving the wettability of SiC particulates during the mixture. Optical microscopy was used to evaluate the gradient distribution of the reinforced SiC particulates and microstructure of prepared FGMMC. The centrifugal action created a gradation of denser SiC particulates along the radial direction in the cast ring, forming outer chilled zone, particle rich, transition, matrix rich, and the innermost zone with porosities. The variation in hardness values also confirms the formation of the functional property along the radial direction.

Advance engineering applications demand new generation materials that are stronger, lighter and cheaper that can withstand extreme service loads for higher performance components in aerospace, aircraft and automotive industries. The present study investigates the effect of TiO2 reinforcement to an AA2014. Four aluminum composites samples were developed through multi-step stir casting by reinforcing varying amounts of TiO2 (1.0–4.0 wt.%). The metallurgical characterization was done by optical microscope. The evaluation of tensile properties such as ultimate tensile strength (UTS) and yield strength (YS) was carried out using Vickers hardness and universal testing machine, respectively. The microstructures were correlated to the corresponding mechanical properties. The results revealed that mechanical properties improved constantly with the addition of TiO2. The microstructure of composite samples revealed that the distribution of TiO2 in the matrix is uniform and grain refinement was also observed due to multi-step stir casting.

In order to clarify the profile control plugging mechanism of polymer microsphere in the low permeability reservoir, and improve the recovery of low permeability reservoir and prolong the stable production time. The swelling property of polymer microspheres are tested and studied by optical microscope and laser particle size analyzer, and through the physical simulation experiment of heterogeneous reservoir was analysed the flooding effect of injecting microspheres with dynamic moisture content of 60%, 80% and 90%. The experimental results showed that, with the prolongation of hydration time, the particle size of the polymer microspheres increases gradually, the long chain molecules are intertwined with each other, and the size of the microspheres is graded. The final recovery was 57.68%, 73.01% and 66.01% respectively. When at the three kinds of dynamic water cut, injected the polymer microspheres into the heterogeneous reservoir. The increase of recovery was 33.74%, 17.98% and 22.29% respectively. According to the optimum injection time, the polymer microsphere flooding is carried out when the dynamic water cut of the reservoir is 60%. The research results provide theoretical and technical support for enhancing oil recovery in low permeability reservoirs.

The aim of this study is to investigate mechanical and microstructural properties of 2024 aluminium tubes (2024 AA) which are produced by flow forming technique and make comparisons between the flow formed 2024 AA, full annealed (2024-O) and solution heat treated then artificially aged (2024-T6) temper aluminium tubes. For this purpose, 70% reduction rate was applied on the 2024-O tempered samples by the flow forming process. The 2024-T6 samples demonstrated higher mechanical properties than 70% thickness reduced 2024 AA due to formation of Al2Cu precipitation. However, it was found that the mechanical properties of the flow formed 2024 AA was almost two times higher than that of the 2024-O sample. Furthermore, grain orientations of these three samples were investigated by the optical microscope. Although any grain orientations were not seen in 2024-O and 2024-T6 aluminum samples, severely grain orientations were observed after the flow forming process.

This paper investigates the impact toughness of low carbon steel weldments produced by the WAAM technique along with the microstructure analysis and hardness survey. The properties are compared with the properties of AISI 1018 steel which is the conventionally rolled steel plate with matching chemical composition. Additive welded specimens were made by GMAW additive welding technique using ER70S-6 electrode (Copper-coated MS wire). The conventional Charpy impact test was performed on the specimens extracted from the additively manufactured bar as per ASTM E23-18 and the microstructure analysis was carried with optical microscopy. Microstructure and chemical composition of both the additive welded and as received specimens indicate relatively homogeneous material properties. An interestingly predominant variation in toughness and hardness was observed between the specimens, though a significant variation in the microstructure is not observed. In general, the results indicate that the additive welding process is capable of producing components with good toughness property when compared to the conventional steel counterpart.

Components of metal matrix composites influence its strength and stability of structures fabricated through them. Aluminium boron carbide (Al 4043/B4C) composite filler rods with varying (0, 2, 4, 6, 8 and 10) wt% of B4C microparticles and 2 wt% of B4C nanoparticles were fabricated successfully by stir casting. The required size of filler rods was produced using electrical discharge machine. TIG welding of Al 6061 plates were carried out using B4C reinforced composite filler rods under optimized conditions. The mechanical and microstructural properties of fabricated weldments were analysed. The optical microscope, FESEM, and TEM images revealed the uniform dispersion of particles and grain refinement of reinforced weldment. The presence of B4C particles in the weldment was also confirmed using X-ray diffraction technique. The obtained results proved that the inclusion of B4C particles into the weldment improved the tensile strength and microhardness of the reinforced weldment by 117% and 21%, respectively.

Generally, defects by word have been determined as abnormality, imperfection, shortcoming, and flaw that impairs quality, function or utility of the materials or system. In manufacturing, the defects or specifically called manufacturing defects are very significant influence for many other properties and performance of the material or system. In literature, manufacturing defects in natural fibre reinforced composites that normally occur during fabrication are classified as misaligned fibres, pockets of undispersed cross-linker, poor wetted resin, resin-rich zone, and voids. The knowledge and determination on manufacturing defect occurrences is important and helps the researcher or manufacturer improve the quality of fabrication process of material and materials performance. This chapter discusses manufacturing defects that have been recognized occurred during the manufacturing process of natural fibre reinforced composite materials by using a non-destructive technique as Optical Microscope (OM) and Scanning Electron Microscopy (SEM). The comeback of manufacturing defects to internal and external fields dictate in many ways of the material properties and performance of final product.

Porosity plays a significant role in concrete strength and durability. It also imparts the randomness in paste and aggregate bonding in cement concrete composite. The paper presents the optical evaluation and analysis of pores in cement mortar sample. The analysis has been done using microscopic images of a thin section of the cement mortar obtained from optical microscope. The mortar samples were prepared by varying its water–cement ratio, different batching process and substituting supplemental cementious material. The microscopic images have processed through ImageJ software for pore size evaluation and its distribution the surface of cement mortar sample. The classification of pores has been made based on its size and their formation for different water–cement ratio, batching processes and usage of cementious material. The overall results obtained through optical evaluation have satisfactory variation and significance in order to understand the progress of hydration and its conductive properties through non-destructive ways.

The influence of hardening on mechanical properties of the low alloy steel grinding balls was investigated. The as received low alloy steel samples were austenitized at 950 ℃ for three different austenitization times and then quenched in oil media. Spectrometer was used to determine the chemical composition of as received alloy steel and optical microscope was used to observe microstructural features. Hardness and Charpy impact tests were performed to measure mechanical properties of the alloy steel samples. The results showed hardness profiles of the as-received steel ball considerably varied from surface to the center. The steel ball exhibited poor hardenability with the thin hardened band at the surface. Compared with the Rockwell hardness of the as received steel samples, the hardness of the as quenched steel at 30 min austenitization time increased while the impact energy decreased. At the higher time, the hardness of as quenched sample decreased, whereas the impact energy remained unchanged. Samples austenitized at 950 ℃ for 30 min. would obtain a maximum hardening and can be used as a baseline for further tempering process.

Friction stir spot welding is a novel single-point solid-state joining process for difficult to weld metals by conventional spot welding processes. In the present study, AA2014-T6 (1.7 mm) and AA7075-T6 (2.5 mm) aluminum alloys were friction stir spot welded using optimized process parameters and computer numerical controlled milling machine. The microstructural and mechanical characterizations of developed welds were completed by optical microscopy and tensile tests. The weld joint showed microstructural features typical to friction stir spot welding. The grain size in weld nugget zone, thermo-mechanically affected zone and heat-affected zone was changed significantly as compared to base metals. The maximum shear load on weld joints was found to be 4.15 kN. Fractography was performed using scanning electron microscopy to identify the mode of failure.

In the present investigation, aluminium matrix-based hybrid composites are developed with the following set of combinations such as n-Al2O3 (2 wt%), n-Al2O3/MoS2 (2 wt% each), n-Al2O3/WS2 (2 wt% each), n-Al2O3/MoS2/WS2 (2%, 1%, 1%, respectively) by using simple and cost-effective stir casting route. Through this study, the self-lubricating aspects of the developed hybrid composites were ascertained. Microstructure and particulate distribution were studied using optical microscope and scanning electron microscope. XRD analysis was used to test the phase present and possible interaction of powders with aluminium matrix. Tensile specimens were made according to ASTM E8 standard and tested on Instron tensile testing machine. Vicker’s micro-hardness was tested by applying a load of 50 kgf for a dwell period of 15 s. Dry sliding wear tests were performed on pin-on-disc tribometer at room temperature using 8 mm diameter and height of 35 mm cylindrical pin samples with a rotating circular disc made of EN31 as counter material at constant sliding speed of 0.5 m/s and at different normal loads of 10, 20, 30 and 40 N. Worn surfaces after dry sliding wear were then analysed under SEM for possible wear mechanism. Results have shown improved density, micro-hardness and ultimate tensile strength of composites. Wear rate and coefficient of friction are observed to decrease with addition of solid lubricants (MoS2 and WS2). The improved wear performance is attributed to high hardness of cast composites and formation of low shear strength tribofilm at the interface.

This study shows the effect of Fe-based hardfacing alloy deposited by GMAW on low carbon steel substrate on the microstructure and wear resistance. Optical microscopy and scanning electron microscopy were performed to examine and evaluate the microstructure of hardfacing alloy. Also, pin-on-disc wear test was performed on the weldment and wear resistance of the weldment was found to increase, due to the formation of carbide. The optical micro-graph of weldment shows the formation of carbide leading to increase in the hardness. No discontinuity and crack were in the weld zone.

The microstructure of a material is its inner morphological features. The microstructure of steel can be diverse and complex depending on the composition, heat treatment, and processing of the alloy, making it difficult to accurately predict the material’s property and composition without physically analyzing the microstructure. Since the microstructure of steel can determine its physical and chemical properties as well as its performance, cost, and efficiency, it is crucial to accurately classify the microstructure. Although microstructure characterization is widespread and well known, it is mostly conducted manually by human experts analyzing pictures taken by either a scanning electron microscope or a light optical microscope. This research aims to automate this processing using state-of-the-art Machine Learning architectures and models to train and learn to differentiate, classify, and interpret the microstructure pictures, employing a pixel-wise segmentation method via U-NET architecture built upon FCNN, Fully Convolutional Neural Network. The method employed several techniques ranging from data augmentation, Amazon computing service, to semantic segmentation. The system achieved a maximum classification accuracy of 98.689%, and predicted the mechanical property with 10% error, providing a robust, accurate approach for the difficult task of microstructure classification.

Micromachining with laser is an established technique used in different industries such as aerospace, automobile, electronic and medical industry. Compared with other processes of drilling holes, laser drilling has the ability to drill very precise micro holes with no tool wear. In the present work, an attempt is made to micromachine straight micro holes using the gas-assisted laser machine on 2 mm thickness steel workpieces. Effect of the input parameters such as laser power and assist gas pressure are studied on the output responses viz. entrance hole diameter, exit hole diameter and taper length. Laser-machined hole surface morphology is analyzed with the help of an optical microscope and scanning electron microscope. Surface metallurgical characterization is carried out to differentiate the recast layer, heat-affected zone (HAZ) and conversion layer by the material elemental composition.

In this study, the erosion wear behaviour of AA5083 aluminium alloy is investigated by slurry pot erosion method. Various sizes of silica sand particles are used to evaluate the erosion wear behaviour of AA5083 alloy by measuring the mass loss. By employing Taguchi L9 orthogonal array, experiments were conducted and optimum process parameters are identified by analysing results of erosion test. Based on the ANOVA, the significant contribution of input parameters is identified. The dominant material removal mechanisms are observed through an optical microscope images, and reasons are discussed in detail.

The objective of the present work is to investigate the formation of intermetallic compounds such as iron aluminides and oxides during the formation of an alloy by melting commercially pure aluminium (Al) billets and adding iron powder (Fe) at 750 °C in the molten aluminium. The exothermic reaction during the addition of ‘Fe’ in the molten ‘Al’ resulted in the formation of more amounts of intermetallic compounds because of the rise in temperature. The composition of the ‘Al’ and ‘Fe’ powder was varied to obtain various alloys. The optical microscopy examination revealed the presence of various intermetallic compounds and oxides in the matrix. The Rockwell hardness survey performed on various samples exhibited a maximum hardness value of 79 in ‘B’ scale for the alloy composition of 60% Al and 40% Fe. A maximum shear strength of 288 Mpa was obtained for the samples containing 65% Al and 35% Fe.

In this investigation, the tensile behavior of laser beam welded 316LN austenitic stainless steel was studied by infrared thermography (IRT) and compared with the base metal tensile behavior. Initially, microstructural characterization of base metal and weld bead was carried out by optical microscopy (OM). Base metal comprises an average grain size of 60 µm and LBW exhibited refined grains at the fusion zone. Very narrow HAZ around 15 µm was recorded at LBW interface. Tensile samples were prepared as per ASTM standard E8, and the test was conducted at room temperature of 26.5 °C. A strain rate of 4.4 × 10−4 s−1 was used during the tensile test of the base metal and LBW samples. Temperature variations of the base metal and weld bead were recorded by an infrared camera at different stages of deformation. Compared to LBW sample base metal sample deformed more and displayed the percentage of elongation as 64.14%, whereas LBW sample displayed less percentage of elongation around 53.2% due to lesser deformation as compared to the base metal. This is attributed to grain refinement during rapid solidification of LBW process at fusion zone. High temperatures were recorded on the base metal (39.2 °C) and center of the LBW fusion zone (30.8 °C) before just the time of fracture. This high temperature of the base metal over LBW sample indicates that the base metal deformed more compared to laser beam welded sample.

This paper presents the effect of different dimple size and dimple distribution on the reduction of surface friction and to produce dimple surface texture using ball-nose milling method. The dimple is a geometrical feature created on flat steel as surface texture to improve tribological performance. The dimple surface texture produced by using ball-end-nose 3-axis CNC milling method. The dimple shape is circular with size varies between 0.5 mm to 3.0 mm. The height of dimples was set constant at 0.25 mm. Dimples were distributed with two arrangement which is linear and radial. Five samples with different dimple size produce for each dimple arrangement. The geometry of dimples then measured using optical microscopy and image analysis. The samples than tested for surface friction with and without lubricant using Universal Testing Machine (UTM) equipped with ASTM D1894 complied apparatus. The lubricated friction test conducted under the constant volume of hydraulic-oil ISO-68 with the face-to-face condition. The results show that the size and distributions of dimple have a significant impact on the friction performance of the textured surface. The friction reduction behaviour was significantly observed on samples with surface texture compared with untextured one, the specimens. When the test load increases, the effect of friction reduction from all forms of dimple size decreases. This study provided insight on improving life of moving parts in machinery and automotive components.

In the present work, particulate reinforced aluminium metal matrix composite has been developed by stir-casting processing technique in which AA5052 is reinforced with 5 wt% B4C-p of 63 µm particles size. The density and abrasive wear of B4C-p reinforced AA5052 MMC were investigated and compared with that of the AA5052 alloy. Abrasive wear test was carried out by pin-on-disc wear test method at different applied loads (5–15 N). The worn out surfaces are analysed by using optical microscopy. The results show that at all applied load, B4C-p reinforced AA5052 MMC gives good tribological properties as well as lower density as compared to the unreinforced AA5052.

The corrosion and electrochemical behavior of high-strength steel AISI 4340 with or without nitrocarburizing heat-treated conditions was studied using salt spray test under 5% NaCl for 24 hours. Electrochemical experiments were also carried out under corrosive environment of a 1N H2SO4. Without heat-treated results obtained by electrochemical test between potential and log of ampere, it yields the value of corrosion potential to 269.2 mV, and in case of heat-treated sample, value obtained is to be −431.918 mV. For heat-treated samples, the rate of corrosion (Icorr) shows a continuous shifting of graph toward a positive direction, whereas in case of without heat-treated sample, the rate of corrosion (Icorr) for HT sample is higher. In salt spray test, the more corrosion product was found to be deposited on surface of heat-treated specimen. Surface morphology of the salt spray specimen is observed under SEM and optical microscope. It reveals large numbers of corrosion pits, with heavily corroded surface. It was caused due to the decrement of the chromium content in high-strength steel with an increase of nitrocarburizing heat treatment temperature. It was observed that with an increase in heat treatment time, Vickers hardness values of 4340 steel increases from 310.8 to 468.2 HV due to increase of nitrogen (N) content over the compound layer.

This chapter describes samples and analytical techniques used for studying the mineralogy and the shock-induced effects in the Yanzhuang meteorite. These techniques are optical microscopy (OM), scanning electron microscopy (SEM) with energy-dispersive X-ray analysis (EDXA), electron probe microanalysis (EPMA), Raman microprobe analysis (RMA), X-ray micro-diffraction analysis (XRMD), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM), instrumental neutron activation analysis (INAA), proton-induced X-ray emission analysis (PIXE), and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS).

In this study, AA6061 plates of 6 mm thickness were subjected to friction stir processing with 50% pin overlapping to produce bulk area fine grain structure using three different tool geometries. Post-processing heat treatment was carried for all samples to investigate the effect of different tool geometries on microstructure and micro-hardness of AA6061. 3D optical microscope and Vickers micro-hardness tester were employed to examine the microstructure and micro-hardness, and results have been reported. From an analysis, it was observed that post-processing heat treatment improved the properties and among three different tool geometries, the samples processed with the hexagonal pin profile yield the best results.

The photoisomerization between an open-ring isomer (1o) and a closed-ring one (1c) in diarylethene 1 film and the needle-shaped microcrystal growth subsequent to photoisomerization were in situ measured with an optical microscope. The 1o film was exposed to UV light on the stage of an upright-inverted microscope and optical and spectroscopic images were in situ observed in order to clarify the mechanism of microcrystal growth in the film. 1o films were prepared on a glass slide and an aluminum (Al) plasmonic chip, which is the Al-coated substrate with a wavelength-size periodic pattern and can provide the enhanced electric field to the chip surface. A plasmonic chip was expected to promote a photoisomerization and a microcrystal growth. Crystal growth of needle-shaped crystal of 1c was observed at the center of a film under the UV irradiation from upright side, but not observed under irradiation from inverted side. On the other hand, crystal growth was found at the film edge by the UV exposure even from the inverted side. Therefore, a high mobility of 1c molecules near the film surface or edge is essential for crystal growth of 1c. Further, alignment of 1c molecules also requires the platform of 1o. The conversion rate from 1o to 1c was larger on the Al grating. By the plasmonic enhanced electric field, when the attenuated UV light was exposed to the film edge from inverted side, the needle-shaped crystals were observed only inside the grating at the conversion rate above 60%. Conversion rate to 1c controlled crystal growth and therefore, crystal growth was promoted inside the grating. In summary, the conversion rate to 1c above 60%, a mobility of 1c near the film surface or edge, and the 1o underlayer platform are required for crystal growth after 1c alignment.

In the present work, laser welding of PWC-11 alloy has been tried in bead-on-plate (BOP) configuration. Experiments have been carried out to determine the range of input parameters for full penetration welding. Laser power (P) and scanning velocity (V) are selected as the input parameters for BOP experiments. Weld width, penetration depth and micro-hardness are the outputs for BOP experiments. The weld profile is analyzed using optical microscope to calculate the aspect ratio and relate its dependence on laser power and scanning velocity. The fusion zone is characterized by scanning electron microscope (SEM) and X-ray diffraction (XRD). Laser power and scanning velocity are to be maintained on the higher level to obtain full penetration weld and to avoid the formation of laser plume. The micro-hardness test has showed that the fusion zone has high hardness value in comparison to the base metal. The increment in the micro-hardness of the fusion zone is due to the formation of phases of oxides and nitride, which is confirmed by the XRD phase analysis. The SEM micrographs reveal the increase in grain size of the fusion zone and EDAX analysis of fusion zone indicates the presence of nitrogen and oxygen. From the present study, it is obvious that the key challenge is to re-establish the present methods of fabrication by laser to avoid the contamination of the future joint by oxygen, nitrogen, carbon dioxide at the time of welding along with weld geometry optimization with a focus on minimization of weld width.

Short fibers are effective reinforcements in strengthening and toughening geopolymer materials. In this chapter, random-dispersed short carbon fiber (fiber length ≤1 mm) or sheet-like carbon fiber preform (fiber length = 2, 7, 12 mm) was developed as starting materials and are used to prepare geopolymer matrix composites. Mechanical properties, fracture behavior, microstructure, and toughening mechanisms of the as-prepared composites were investigated by three-point bending test, optical microscope, and scanning electron microscopy. Effects of fiber surface treatment and high-temperature treatment on the mechanical properties of the composites were also studied. The results show that Csf/geopolymer composites exhibit apparently improved mechanical properties and an obvious non-catastrophic failure behavior. The predominant strengthening and toughening mechanisms are attributed to the apparent fiber bridging and pulling-out effect based on the weak fiber/matrix interface.

Al LM13 alloy reinforced with MgO particulates of 0–10wt% in terms of 2wt% were developed by the stir casting technique and the prepared samples were characterized on the basis of microstructure, Brinell hardness, XRD, and SEM. The hardness test indicated increased hardness of the MMC as the MgO particulate percentage increased. Optical microscope studies indicate the MgO particulate distributed randomly in the Al LM13 matrix. The presence of MgO was also identified in XRD. The wear performance of Al-LM13/MgO composite was examined on pin-on-disk equipment. The experimental studies on the MgO particulate increased the wear rate and decreased proportionately indicating the active role of the MgO particulate in reducing the wear. SEM suggests the presence of adhesive and abrasive wear mechanism with evidence of transfer films. The development in the wear resistance is due to the presence of MgO particulates in the Al LM13 matrix alloy.

The aim of this investigation is to characterize the effect of process parameters applied to the laser metal deposition of Al–Cu–Ti coatings on titanium substrate (Ti–6Al–4V). After the deposition process was completed, a new hybrid coated surface emerged with improvements in the following areas: improved thermal, mechanical, and metallurgical properties. During the laser metal deposition procedure to obtain a hybrid coating on Ti–6Al–4V, certain process parameters were employed to achieve the optimum results which are the scanning speed (1.0 m/min) and the laser power of the procedure, which was varied between 900 and 1000 W. The microstructural analysis was carried out using the scanning electron microscope (SEM) and an optical microscope (OPM). The mechanical properties of the samples were characterized using microhardness test.

In this article, the investigation on the tolerances achievable on two cavities, circular and straight channels, are presented. In the case of circular cavities, circularity has been evaluated while in the case of straight channels, straightness has been evaluated, respectively. The investigation begins by fabrication of cavities in series of three having a nominal dimension on polymethyl methacrylate (PMMA), also known as acrylic using CO2 laser. After that, the Olympus optical microscope was used to examine the geometry of the fabricated microcavities and their tolerances have been evaluated after analyzing these geometries by profile projector and Olympus Analysis Software. It was found that the average circularity tolerance of circular micro-geometries was estimated as 1.34 μm and the average straightness tolerance of microchannels was estimated as 8.66 μm.