Search

Bioceramics have been widely utilized for orthopaedic applications in which the biocompatibility and mechanical properties of the materials are vital characteristics to be considered for their clinical use. Till date, extensive studies have been devoted to developing a range of scientific ways for tailoring the microstructure of bioceramics in order to attain the trade-off of mechanical properties and biocompatibility of the final product. Owing to low reactivity, earlier stabilization and longer functional life of bioceramic, the developed implants are capable of replicating the mechanical behaviour of original bone. As the safety of the patient and its ultimate functionality are the ultimate goal of the selected implant material hence, the present literature survey investigates and brings forth the important aspects associated to the mechanical, biological and microstructural characteristics of bioceramics employed in orthopaedic applications. The review paper majorly focuses on effective utilization of various materials as an additive in bioceramics and processing techniques used for enhancement of properties, enabling the use of material in orthopaedic applications. The influence of various additives on the microstructure, mechanical properties and biological performance of developed bioceramics orthopaedic implants has been elaborately discussed. Furthermore, future prospects are proposed to promote further innovations in bioceramics research.

Over the past few decades, consistent efforts have been made by numerous steel and ironmaking industries in the direction of reutilizing the “by-product” of rolling mill i.e. the mill scale in wake of ever rising cost of superior quality lump ores and its unavailability. Also, utilization of low-grade coal composing higher content of volatile matter has constantly been another concern for the researchers. Rajasthan has a vast reserve of low-grade coal. The objective of the study undertaken is to utilize both of the aforestated raw materials (of Indian origin) in a solid gas reactor. It is devoted to assess and study the reduction of mill scale in the presence of single gaseous reductant (i.e. CO gas). The optimal process parameters (i.e. reduction temperature, mill scale size, reduction time and mill scale to coal ratio) were also analysed during the reduction. Current study investigates the impact of mill scale size (300 to 825 µm), reduction temperature (800 to 1100 °C in steps of 100 °C), reduction time (60–240 min), and mill scale to coal ratio (1:1, 1:2, 1:3 and 1:4) on accomplishable Fe (metallic iron) percentage and its metallization. Lower mill scale size (300 µm) particles, higher reduction temperature (1100 °C), higher reduction time (240 mins), and mill scale to coal ratio (1:3) yielded higher percentage of metallic iron content (76.28%) and metallization (96.75%). During the entire study the flow rate of CO is maintained at 4.5 LPM (litres per minute). The chemical analysis of mill scale is carried out using X-ray fluorescence (XRF), and mill scale particle size and dispersion of mill scale is analysed by scanning electron microscope (SEM). The presence of bright and dark phases in the FE-SEM micrographs confirm the presence of metallic and not metallic elements. It became apparent that reduction of mill scale using low-grade coal presents the most promising results with the solid gas reactor yielding a greater degree of metallization as compared to the rotary kiln and RI-RDI furnaces.

ZnO thin films were fabricated by an RF-sputtering deposition technique on Si and Glass substrate and then was used as the active semiconductor material in thin-film transistors (TFTs). The TFTs were fabricated in a bottom gate with top contact electrode structure with high-k TiO2 as the gate insulator and Au used for the source and drain electrodes but Al for the gate electrode. TFTs were annealed at 500 °C for 1 h using sputtering inside the substrate heating facility. The TFT with a W/L (4/1) channel ratio found high field-effect mobility of is 5.19 cm2/Vs and drain current on–off ratio at 107 with a low threshold voltage.

Present investigation envisages kinetics involved in solid state reduction of mill scale surrounded by lean grade coal powder in static and dynamic processes. Research aims to evaluate the reduction potential of economically available lean grade coal from Rajasthan in the reduction of mill scale. Experiments were carried out by mixing equal proportion of mill scale and coal and charging into the rotary kiln furnace. The variables studied are time and temperature. The reduction was done at temperatures ranging from 950 °C to 1050 °C. The degree of reduction of mill scale was calculated at 60 to 240 min. The experiments were statistically designed to assess each variable quantitatively and compared. The results indicated an increase in the degree of reduction with time and temperature. With the increment in temperature up to 1000 °C and holding time 240 min, 77.71% of metallization is achieved. The results showed a definite relation between reduction with time and temperature. Using the technique of empirical relation of transformation, the kinetics involved in solid state reduction of iron is studied for the processes. It is empirically calculated that the kinetics of reduction for the process of reduction in rotary kiln using the experimented setup. The Taguchi method, and analysis of variance (ANOVA) for the selected parameters to investigate the major effects and to assess the optimal process parameters show that, temperature is the most significant parameter amongst all whereas the mill scale size is the least affecting parameter. Based upon the analysis the optimized parameters obtained were temperature (at 1000 °C), mill scale to coal ratio (minimum 1:3), time (minimum 180 min), and mill scale size (minimum 425 to 600 µm). The microstructural characterization (XRF, XRD and FE-SEM. FE-SEM) conforms the formation of porous mass due to the solid state reaction between mill scale and coal.

The performance of thermoelectric generators (TEGs) besides depending on material’s figure of merit, is also a function of the module design like the heat exchanger design, thermoelectric leg size, configuration, and contact resistances. Optimizing these parameters using conventional experimental methods is quite time-consuming and inconvenient. Taguchi optimization method could be used an efficient technique to predict the performance of a TEG module with less number of experimental runs as compared to the customary techniques. The most commonly used materials in thermoelectric applications in the medium temperature range (400–900 K) are the PbTe alloys and Mg2(Si-Sn) based alloys. N-type Mg2(Si-Sn) alloys often being integrated with higher manganese silicide (HMS) for fabricating TEGs, pose problems in maintaining the long-term stability of such generators owing to the imperfectly matched thermomechanical properties between these materials. Therefore, it is required to evaluate a TEG system that is completely made out of magnesium based thermoelectric alloys (both p- and n-type). The current study examines the scope of Mg2(Si-Sn) thermoelectric generators based on the numerical modeling technique along with employing Taguchi and ANOVA techniques for improving the overall system output. A TEG system comprising of 36 modules is built using numerical modeling which is followed by optimization of pivotal design parameters through the Taguchi and ANOVA methods. Optimal control factor settings obtained from the Taguchi method result in output power and conversion efficiency values of 90.04 W and 9.08% respectively. The predicted optimal output Ypredicted is also calculated, the respective values obtained for output power and conversion efficiency are 59.9 W and 9.12%. From ANOVA analysis, it is observed that the most significant variable for power output is the cross-sectional area with a percentage contribution of 35.22% and that for the conversion efficiency is the temperature difference between the two ends of the TEG having a percentage contribution of 97.73%.

Martensitic steels possess higher strength and toughness as the carbon content is minimum and strengthened by precipitation hardening. Hence various factors such as chemical composition, production techniques, heat treatments influencing the properties of martensitic steel were chosen for review. An attempt has been made to understand various available microstructural characterization techniques with their unique features and also predictions as made with the help of thermo-kinetic simulations for microstructure evolution. It is witnessed that vacuum induction melting is preferred for steels to achieve the highest purity. For understanding the evolution of microstructures during heat treatments, studying precipitation kinetics through micrographs has emerged very important for identifying strengthening mechanisms. Professional software can be used for prediction purposes, which also saves a lot of time, effort, and cost. Including Atomic Probe Tomography for microstructural characterization, helps in identifying nano-sized coprecipitation mechanisms.

This paper reviews the basic understanding of Mg-based thermoelectric materials and various approaches for increasing their thermoelectric efficiency. Recent developments in terms of enhancement of electrical properties and reduction of thermal conductivity of Mg2(Si,Sn) materials through experimental investigation and applying modeling approaches are discussed in detail. Further, the role of deformation and heat treatment analysis for achieving optimum thermoelectric properties in this material system and its prospects for further developments as a commercially viable solution is enumerated. The solid solutions of Mg2X (X = Si,Ge,Sn) thermoelectric material are identified as the most favorable alloy class of thermoelectric materials for application in the intermediate temperature range (400–800 K). The reason for Mg2X alloys becoming the preferred choice over others is because they are cheap, abundant and non-toxic. Improving the efficiency of magnesium-based thermoelectric materials through various advancements in experimental methods has appeared as a matter of great commercial importance. However, theoretical understanding of the phenomenological issues confronting the attainment of desirably high thermoelectric properties has not been widely touched upon; this leads to enormous opportunities for optimizing the figure of merit of thermoelectric materials through numerical modeling and simulation techniques. Also, deforming the alloys has been proved to be favorable for the thermoelectric performance of the material; a lot of work has been carried out for other classes of thermoelectric materials, but there is a disparity in interpreting the deformation behavior of Mg2Si1−xSnx alloys and its impact on thermoelectric properties due to lack of adequate efforts to conduct systematic investigations in the area of concern.

The paper reports synthesis of graphene oxide (GO) using modified Hummer’s method and its hydrothermal assisted reduction to produce reduced graphene oxide (rGO) for supercapacitor applications. Synthesized GO and rGO were characterized using Raman spectroscopy and their Id/Ig ratio was found to be 0.94 and 0.87, respectively. Scanning Electron Microscopy (SEM) was also performed on samples for detailed surface morphology information. UV-Vis spectroscopy was employed to investigate optical properties. FT-IR spectroscopy was utilized to get the information of attached functional groups and electrochemical characterization (cyclic voltammetry) was used to test the charging discharging behavior of the material. The specific capacitance of synthesized rGO was found to be 105F/g.

Mg2Si based thin films are a promising candidate for thermoelectric applications in the mid temperature range. The main advantages of these films are their low density, abundance of the elements used, good stability and environmental friendly nature. Nano structuring is considered to be useful tool to enhance the properties and hence thin films have been studied; although fabrication of Mg2Si thin film has been difficult due to difference in properties of magnesium and silicon. Semiconducting Mg2Si thin films were deposited on silicon substrate by radio frequency magnetron sputtering at low substrate temperature following a distinct approach. X-ray diffraction (XRD) and Field – Emission Scanning Electron Microscopy (FE-SEM) with EDS were done to study the phases, elemental composition and microstructure of these films. XRD results showed single phase Mg2Si formation. SEM results revealed granular nature of films and no cracks were observed. XPS was employed to study the chemical composition of films. The thin films were studied for their electrical transport behaviour through I-V and Hall measurements. Maximum conductivity of Mg2Si thin films was found to be ∼ 103 S/m and a carrier concentration of 5.14 + 19/cm3 was obtained for 300 nm thick film. The films showed n type nature.

This paper reports the results of investigation on 0.1C-17Mn-5.5Ni-1.8Al-2.7W-4.6Mo-2.3Cu-0.002B steel designed to assume excellent combination of strength and toughness. The air induction melted steel was subjected to hot forging at 1200 °C followed by hot rolling in six passes from 1100 °C. The rolled samples were reheat-quenched from 1050 °C in iced water. The quenched samples were isochronally aged at temperatures within 500-650 °C at interval of 50 °C. The mechanical properties were determined by hardness measurement and tensile testing. Structural characterization was accomplished by x-ray diffraction, optical and electron microscopy. Differential scanning calorimetric study was conducted to understand the precipitation kinetics. A typical age-hardening behavior was noted in the aged samples due to the precipitation of M2C and Ni3Al. Strain hardening of martensite, precipitation hardening due to the presence of nanosized precipitates and Orowan hardening were found to be instrumental in attaining a maximum hardness of 723 HV. The microstructure of aged samples consists of retained austenite, e-martensite, α′-martensite and uniformly distributed nanosized precipitates of Ni3Al and M2C, lying broadly within two different size regimes. The sample peak aged at 550 °C attained a strength of 1.4 GPa at a total elongation value of 25%. The combination of high strength and high ductility has resulted from precipitation strengthening, TRIP phenomenon and high degree of structural fineness.

The effect of multiwall carbon nanotube (MWCNT) content on the physical and mechanical properties of Fe-MWCNT composites has been studied. High-energy ball milling (HEBM) is employed to produce the composite powder; following this, spark plasma sintering (SPS) process has been adopted for powder consolidation. The composite powder and the sintered products were subjected to structural characterization by XRD. Microstructural studies were carried out by optical, field-emission scanning and high-resolution transmission electron microscopy. While Fourier transform infrared spectroscopic study of composites was done to understand the bonding characteristics, Raman spectroscopy was employed to assess the structural damage of MWCNT after HEBM. The effects of processing on the behavior of C-C, C-O and Fe-O bonds are studied by x-ray photoelectron spectroscopy. Microhardness and compressive strength of composites are also determined. Finally, magnetic and electrical properties of the composites were characterized. It was observed that optimized ball milling conditions help to preserve the structural identity of MWCNT. Consolidation by SPS insured good interfacial bonding. The microhardness and compression strength are significantly improved in MWCNT-reinforced iron matrix composite. MWCNT has appreciably improved the electrical conductivity of the composites. Tethering of MWCNT by iron oxide has led to appreciable improvement in saturation magnetization till 3 wt.% MWCNT.

Copper metal embedded fullerene C60 thin films are deposited on various substrates via resistive heating co evaporation technique. Rutherford back scattering simulated spectrum confirms the thickness and composition of thin film to be ~ 32 nm and ~ 18 at%, respectively. The deposited thin films are irradiated by 120 MeV Ag ion beam for different fluences within the range, from 1 × 1012 to 3 × 1013 ions/cm2. UV–vis absorption spectroscopy study reveals the appearance of surface plasmon resonance (SPR) band in pristine thin film at ~ 622 nm; this phenomenon is ascribed to the presence of copper nanoparticles in C60 matrix. The SPR band intensity increases with rising fluences, which is suggestive of the growth of Cu nanoparticles. Growth of Cu nanoparticles is further confirmed by transmission electron microscopic (TEM) and X-ray diffraction (XRD) study. Whereas the conversion of C60 into amorphous carbon (a-C) is confirmed by Raman spectroscopy, XRD results of pristine Cu–C60 thin film record the presence of Cu2O within the nanocomposite thin film. However, both X-ray photoelectron spectroscopy (XPS) and XRD studies on irradiated thin film samples authenticate the growth of Cu metal nanoparticles with concurrent removal of oxygen.

In this paper, we investigated the effect of film thickness on structural, surface morphology and optical properties of ZnO thin films grown by pulsed laser deposition (PLD) method. Thickness of the films was varied by keeping all other PLD parameters same to investigate thickness dependence on the structural and optical properties of ZnO thin films. The prepared thin films have been characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), UV- visible (Uv–Vis) and photoluminescence (PL) spectroscopy. XRD confirms the formation of crystalline c-axis orientated hexagonal wurtzite structure of ZnO thin films. AFM depicts that roughness and grain size of the ZnO films increase with increase in the films thickness. The direct optical band gap of the ZnO films calculated using Tauc's plot increase from 3.28 eV to 3.34 eV as the thickness of the films varies from 55 nm to 220 nm. The high quality c-axis orientated ZnO thin films with minimum strain and tuneable optical properties could be used as a transparent conducting oxide (TCO) for optoelectronic applications.

Introduction: Asymptomatic bacteriuria (ASB) is the presence of actively multiplying bacteria within the urinary tract with absence of any symptoms, resulting in adverse pregnancy outcomes. This research study was done in order to review prevalence, antimicrobial susceptibility profile, and factors associated with ASB occurring in female patients who are pregnant and being treated at a tertiary care hospital in Lucknow, India. Method and Materials: This is a cross-sectional study done among 216 pregnant women attending a hospital for antenatal check-ups. Clean catch midstream urine samples were collected and examined microscopically, and semi-quantitative culture was done on blood agar and MacConkey agar. Isolates were identified by colony morphology and biochemical tests, and antimicrobial susceptibility testing was done by using the Kirby-Bauer method. Results: Of the 216 pregnant women, 36 (16.7%) tested positive for ASB. The female gestational period, haemoglobin level, and BMI were significantly associated with ASB. Logistic regression also showed that higher haemoglobin level was less likely to ASB (AOR = 0.42, 95% confidence interval: 0.202–0.88, p = 0.021). The predominant and usual isolates were E. coli (n = 22, 61.1%), followed by Cons (n = 6, 16.7%), and S. aureus (3, 8.3%). All Gram-negative isolates were mostly sensitive to most of the drugs like piperacillin-tazobactam, cefepime, nitrofurantoin, and meropenem but were 100% resistant to ampicillin. Similarly, Gram-positive isolates were sensitive to ampicillin, vancomycin, linezolid, and nitrofurantoin but 100% resistant to co-trimoxazole. Conclusion: The present study shows the existence of ASB was 16.7% among women who are pregnant. Pregnancy duration, haemoglobin level, and BMI were significantly associated with ASB. The isolates identified more frequently were E. coli (61.16%), Cons (16.7%), and S. aureus (8.3%). All isolates which were Gram-negative were mostly sensitive to most of the drugs but were 100% resistant to ampicillin. Similarly, Gram-positive isolates were sensitive to most of the drugs but 100% resistant to co-trimoxazole.

In the present work, a ternary Heusler alloy of composition Ni50Mn40Sn10 with a high martensitic transformation temperature has been prepared by arc-melting technique. The crystal structure of the obtained alloy is investigated by X-ray diffraction. The microstructure of the specimen sintered at 950°C for 72 h followed by ice-water quenching shows needle-like martensitic structure. Energy dispersive spectroscopy is utilized for compositional study. The differential scanning calorimetry result shows that the alloy undergoes a martensitic transformation at 190°C upon cooling. The M–H curve suggests paramagnetic nature of the martensite phase at room temperature. The present alloy system has a great potential to be used for high-temperature shape memory applications. Experimental data of this study may be useful for developing Ga-free high-temperature shape memory alloys.

High-energy ball milling (HEBM) of mixtures of iron powder and multi-walled carbon nanotube (MWCNT) has been performed in an attempt to synthesize nano-grained steel. Even after exposure to a harsh HEBM conditions, the MWCNTs are seen to have retained their structural identity, and therefore, an MWCNT-reinforced steel matrix composite could be finally produced. Moreover, the study has revealed that the minor addition of copper leads to a significant reduction in grain size of ferrite in the so-produced steel matrix–MWCNT composite. It is also noticed that the fine grain structure of ferrite remains intact even after consolidation of the powder composite by spark plasma sintering, followed by hot forging. The micro-hardness values obtained for the composites (with/without copper) are observed as comparable with the submicron-grained steels, so far reported in the literature.

Iron-Multiwalled Carbon Nanotubes (iron-MWCNT) were synthesized using varied durations of optimized high-energy ball milling (HEBM) of powder mix. Characterization and furthermore structural stability of these nanotubes were ascertained using state-of-the-art techniques such as Scanning and high resolution Transmission Electron Microscopy, X-ray Diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared Spectroscopy (FTIR), Raman Spectroscopy, and Differential Scanning Calorimetry (DSC). Additionally, magnetic properties were measured by Vibrating Sample Magnetometer (VSM). Our results indicate that structural integrity and therefore characteristic properties of MWCNTs such as (magnetic, electrical and mechanical properties) are retained up to 60 min post ball milling. Expectedly, HEBM led to partial destruction of C C bonds, however, the amount of carbon atoms released by bond disruption is insignificant and heavy super saturation of iron with carbon and extensive precipitation of carbides during heating is untenable. Optimal ball milling ensures the formation of smooth and continuous interfaces between the matrix therefore reinforcing the MWCNTs. The excellent interfacial structure so achieved has significantly improved the magnetic properties of iron-MWCNT nanocomposites synthesized in this study.

Evolution of microstructure in the patented near-eutectoid steel, forged under varying situations, is critically examined in the present investigation. Steel with 0.74 wt.% carbon is isothermally annealed at 500 °C to obtain fine pearlite microstructure. Steel samples, so patented, are subjected to mechanical deformation by forging at various temperatures with different amount of thickness reduction. Microstructural analyses have revealed that mechanical deformation by forging at lower temperatures brings about partial dissolution of cementite, which is followed by the formation of e-carbide in the microstructures. In contrast, cementite is precipitated within ferrite matrix upon warm or hot forging at higher temperatures. It is further observed that increasing deformation percent during low-temperature forging reduces interlamellar spacing of pearlite, whereas an opposite trend is noticed in case of deformation at higher temperature; moreover, deformation induced the change in interlamellar spacing and formation of fine carbide phases in microstructures has caused appreciable enhancement in hardness of the steel.

Thermoelectric generator (TEG) that works in medium and high temperature ranges has appeared as a necessity in combating with the waste heat management from various industries. Therefore, design of TEG with thermoelectric materials capable to exhibit high capacity for thermoelectric power generation is of emerging technological interest. It is known that alloys based on Mg2(Si, Sn) and PbTe thermoelectric materials are best suited for the intermediate temperature scale (400–900 K). For constructing a TEG, higher manganese silicides (HMS) are often used for integration with n-type Mg2X (Si, Ge, Sn) alloys. The thermo-mechanical property-mismatch reasons out the option for such a combination in fabrication of a sustainable thermoelectric generator. This makes one focus on evolving a generation system that comprises of both n- and p-type thermo elements prepared from suitable Mg2X (Si, Ge, Sn) alloys. The present research analyses the feasibility of designing a Mg2 (Si, Sn) alloy based thermoelectric generator by modeling approach. It presents a comprehensive take on the effect of thermoelectric leg dimensions and contact resistances on the output voltage, output power and efficiency, with alteration in the operating temperature span. The COMSOL modeling results indicate that the power output reduces considerably with increment in the thermoelectric leg length, while the conversion efficiency enhances. Contrarily, augmenting the cross-sectional area of a thermoelectric leg follows an opposite trend i.e., it increases the power output and decreases the conversion efficiency. The power output and the conversion efficiency values diminish when contact resistances are considered in the modeling study. This study also incorporates an efficient heat exchanger system including contact resistances and conductive and convective heat losses for accurate estimation of power output and efficiency of the optimized TEG module.

Nanocrystalline thin films of Ni–Ti shape memory alloy are deposited on an Si substrate by the DC-magnetron co-sputtering technique and 120 keV Ag ions are implanted at different fluences. The thickness and composition of the pristine films are determined by Rutherford Backscattering Spectrometry (RBS). X-Ray diffraction (XRD), atomic force microscopy (AFM) and four-point probe resistivity methods have been used to study the structural, morphological and electrical transport properties. XRD analysis has revealed the existence of martensitic and austenite phases in the pristine film and also evidenced the structural changes in Ag-implanted Ni–Ti films at different fluences. AFM studies have revealed that surface roughness and grain size of Ni–Ti films have decreased with an increase in ion fluence. The modifications in the mechanical behaviour of implanted Ni–Ti films w.r.t pristine film is determined by using a Nano-indentation tester at room temperature. Higher hardness and the ratio of higher ha...

Fullerene C60 thin films with a thickness of ∼120 nm were synthesized by thermal evaporation method on glass substrate. The deposited thin films are irradiated with 90 MeV Ni ions in the fluence range from 1 × 109 to 3 × 1013 ions/cm2. The pristine and irradiated fullerene C60 thin films are examined to study the effect of energy deposition by 90 MeV Ni ions on the optical and structural properties by UV–visible absorbance spectroscopy and Raman spectroscopy, respectively. UV–visible absorbance spectroscopy study reveals that the absorbance peaks decline with the fluence and at particular fluence (∼3 × 1013 ions/cm2) all the absorbance peaks disappear. Apart from this, a decrease in band gap has also been observed with increasing fluence. Raman study confirms that the effect of 90 MeV Ni ion irradiation is observed in two phases. In the lower fluence region, polymerization of C60 molecules is observed and in higher fluence region, destruction of the molecules comes into picture. At fluence 3 × 1013 ions/cm2, fullerene C60 thin film transformed into amorphous carbon (a-C). The transformation of fullerene into a-C is also confirmed through conductivity measurement.

Cu-C60 nanocomposite thin films are synthesized by co-deposition restive heating method on glass, silicon, and TEM grid substrates. Rutherford backscattering spectroscopy (RBS) analysis is used for determining the composition of Cu and thickness of thin film which one found to be ∼13 at% and ∼28 nm, respectively. The deposited thin films are irradiated with 100 keV Ag ion at different fluences ranging from 1 × 1014 to 3 × 1016 ions/cm2. Being of low energy, Ag ions got implanted in SiO2 substrate up to a depth of 30–40 nm that results in wide surface plasmon resonance (SPR) band in combination with SPR of Cu nanoparticles. UV-visible absorption spectroscopy demonstrates the SPR peak arises due to copper nanoparticles embedded in fullerene C60 matrix on irradiation of nanocomposite thin film and its variation under implantation of Ag nanoparticles in SiO2 substrate. Structural modifications due to ion irradiation are analyzed by Raman and transmission electron microscopy (TEM). Raman spectroscopy study reveals the transformation of fullerene C60 into amorphous carbon (a-C) with increasing fluence. Variation in particle distribution is observed under TEM. The average particle sizes are found to be ∼4 ± 0.7 and ∼6 ± 0.4 nm for pristine and 100 keV Ag ion-irradiated thin films, respectively. Atomic force microscopy (AFM) confirms the increase in grain size with increase in roughness of nanocomposite thin films under the effect of implantation. X-ray photoelectron spectroscopy (XPS) confirms the presence of Cu and C from their chemical bonding in Cu-C60 nanocomposite thin films.

In present investigation, warm working characteristics of ferrite were studied for 0.044C-1.51Cu-1.52Mn-0.064Ti steel by Scanning Electron Microscopy images, Energy-dispersive X -ray spectroscopy and Transmission Electron microscopy. The specimens were subjected to multi-pass hot rolling at 800 °C and 850 °C with holding time of 10 minutes. The result shows that Cu precipitation take place during the formation of warm worked ferrite and there is evidence of formation of Cu precipitates at the boundaries of newly born ferrite grains. This has the implication of inhibition of grain boundary movement; hence ferrite grains of size 1-4 micron are formed. It is also observed that the intra-granular fine precipitates of titanium carbosulphides/ sulphides, copper particles at the boundaries and irregular and massive oxysilicates at the large angle grain boundaries.

The primary aim of the present investigation is to study the effect of temperature and strain rate on dynamic re-crystallization behaviour in 0.05C-1.52Cu-1.51Mn steel. The flow diagram for single hit compression as well as double hit compression with a pre-strain of 0.4 using thermo-mechanical simulator (Gleeble) in plain strain compression is obtained. It is found that single hit compression shows dynamic re-crystallization behaviour while double hit compression shows dynamic recovery. There is an indication of serrations in flow diagram at lower deformation temperature and strain rate is observed in case of double hit compression. The Cu precipitate of size 10 nm is found in the process adopted in the experimentation. It is also observed that high deformation temperature

In this work, low carbon of extremely fine grain structure was produced by mechanical alloying of powders of iron and activated charcoal with minor addition of copper (Cu); mechanically alloyed powder was consolidated by spark plasma sintering to obtain a high-density compact. The steel so produced was subsequently subjected to forging followed by normalizing. The characterization was carried out by means of nanoparticle size analyzer, X-ray diffraction, optical microscopy, scanning electron microscopy, transmission electron microscopy, and Vickers microhardness testing. The microhardness value obtained for the steel was found to be significantly high and comparable with that of nanocrystalline/ultrafine grained steels produced by other routes. The increased hardness resulted from the smaller grain size and presence of finely dispersed ultra small sized copper and cementite precipitates.

This article highlights the usefulness of nickel as a metal. Discussion is made about the global sources of this metal in context of its abundance and suitability of extraction. The processes of extraction from nickel ores are mentioned. Narrating its major physical properties, enumeration is made of different nickel alloys and their uses. Finally the novelty of nickel alloys as immune to chemically and mechanically aggressive service condition is discussed in consideration of austenitic stainless steels as benchmark.

This paper reports the beneficial effect of silver addition (~0.1 wt%) on the structural stabilization of multiwalled carbon nanotube (MWCNT) reinforced in iron matrix by way of high energy ball milling (HEBM) and spark plasma sintering (SPS). Silver added Fe - x wt% MWCNT (x = 1, 2, 3 and 4) composites were prepared by HEBM followed by SPS. Structural characterization of silver bearing composite powder and its sintered mass was carried out by XRD. The structural damage of MWCNT after HEBM was assessed by Raman Spectroscopy. As a support, Fourier Transform Infrared (FTIR) spectroscopic study was used to look into the bonding characteristics. Detailed microstructural studies by optical, field emission scanning (FESEM) and high-resolution transmission electron microscopy were employed to further assess structural stabilization and evolution of micro constituents during processing. Finally, magnetic and electrical properties of the composites were determined. It was revealed that minor addition of silver aids in restoration of the structural integrity of MWCNT in iron matrix composite. Moreover, it was noted that silver added composite could achieve a contamination free matrix–reinforcement interface. It is propounded that silver atoms tether MWCNT surface and behave like coating over MWCNTs. Conductivity of silver doped iron-4 wt% MWCNT composites exhibited a conductivity value higher than that of electrical conductivity grade (EC grade) aluminum. Saturation magnetization of silver doped Fe-MWCNT composite was increased by 25% over pure iron at 3 wt% MWCNT. The observed improvement in properties of composite is ascribed to tethering of silver particles at MWCNT surface; this gave rise to better interfacial bonding and the physical properties.

In the present study, efforts have been made to assess and study the reduction of mill scale in the presence of single gaseous reductant (i.e. CO gas) in RI-RDI (reducibility index (RI) and reduction degradation index) equipment. While conducting this study optimal process parameters like reduction temperature, mill scale size, reduction time and mill scale to coal ratio were analysed. An exceptional experimental profile is maintained inside the furnace to attain the optimum metallization. The mill scales are reduced inside the furnace and the extent of reduction is evaluated from the weight loss. Post conducting reduction in the RI-RDI test apparatus, the reduced mill scale is characterized for the microstructural and morphological studies using SEM, EDS, XRD. The most optimum results of the reduction were attained in RI-RDI apparatus giving iron content of (metallization) 89.15 % at the reduction temperature of 1050°C for 240 mins holding time. During the entire study on RI-RDI apparatus, flow rate of CO is maintained at 4.5 LPM (litres per minute) and N2at 10.5 LPM. Finally, the degree of metallisation in the sample as well as the product material is calculated by using the chemical analysis process (dichromate and ferric chloride method). The characterization of produced iron powder was done by chemical analysis, XRD, and FE-SEM. The FE-SEM results confirm the presence of resultant pore characteristics. It is observed that mill scale can be significantly reduced to metallic iron by utilizing lean grade coal.

Fullerene C 70 thin films were deposited by resistive heating on glass substrates and the thickness were approximated to be 150 nm. The effect of energy deposition by 55 MeV Si ions on the optical and structural properties of the prepared thin film samples is investigated. The samples were irradiated with 55 MeV Si ions within fluence range from 1 × 10 12 to 3 × 10 13 ions/cm 2 . For optical studies, the pristine and the Si ion irradiated samples are examined by UV–visible absorption spectroscopy and Raman spectroscopy. UV–visible absorption studies reveal that the absorption peaks of irradiated samples decrease with a decrease in the band gap of the thin films. The damage cross-section ( σ ) and radius of damaged cylindrical zone ( r ) are determined as ∼0.6 × 10 −13 cm 2 and ∼1.41 nm, respectively from the Raman spectra. Raman studies also suggest that at higher fluence (up to 3 × 10 13 ions/cm 2 ), the damage caused by the SHI results in partial amorphization of fullerene C 70 thin film. Modification in the surface properties has been investigated by atomic force microscopy; it has revealed that the roughness decreases and average particle size increases with the increase in fluences.

The effect of energy deposition in fullerene C70 (∼150 nm) thin film deposited by resistive heating method on glass, quartz and silicon substrates was investigated. The samples were irradiated with 90 MeV Ni ion beam at the fluences ranging from 1 × 1012 to 3 × 1013 ions/cm2. The pristine and Ni ion irradiated samples were examined for morphological and optical changes by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), UV–visible absorption spectroscopy and Raman spectroscopy. After ion irradiation, bigger grains are shown on surface as revealed by SEM analysis indicating the agglomeration of the smaller particles into bigger particles at the surface. UV–visible absorption studies reflect that the direct band gap of the film decreases with increase in ion fluence. At higher fluence, fullerene C70 is transformed into amorphous carbon (a-C) which is confirmed by Raman spectroscopy. The damage cross-section (σ) and radius of the damaged cylindrical zone (r) are approximated to be ∼1.72 × 10−13 cm2 and ∼2.3 nm, respectively using Raman active vibrational modes.

The present work reports the fabrication and characterization of high mobility thin-film transistors, where zinc nitride is used as the active layer (∼100 nm thick). For the TFT, the active layer was deposited at room temperature on different substrates (Si-p type and glass) by RF magnetron sputtering method and annealed at 350 °C post-fabrication and HfO2 was used as the gate insulation layer (∼50 nm thick). The obtained value of field-effect mobility was greater than 5 cm2 Vs−1, with optical bandgap ∼3.07 eV. The two MIS (metal insulator semiconductor) structures were analyzed using I–V and C–V measurements. It is demonstrated that Zinc Nitride is a potential candidate to be used as an active layer in TFT fabrication. The threshold voltages of the device built on Si and glass substrates were obtained as 0.8 volts and 2.6 volts respectively.

Bi doped Mg2Si0.4Sn0.6 had been synthesised in a high energy ball mill followed by compaction using a sintering hot press. The structural and compositional characterization of sintered mass indicated the formation of a highly densified single-phase product. The microstructure of the hot-pressed samples had been critically assessed. Thermoelectric properties were measured between room temperature and 723 K. A decrease in electrical conductivity was found with the increase in temperature but the Seebeck coefficient showed a reverse trend justifying the attainment of degenerate semiconducting behaviour. Meanwhile, the lattice thermal conductivity was subdued to 1.5 W/mK at 623 K. However, the highest zT value of 0.8 was achieved at 723 K. Moreover, the detailed X-ray photoelectron spectroscopic analysis was carried for the determination of binding energy of the constituent elements in the experimental alloy; it also provided the correct estimation of atomic percentage of the concerned elements. The Raman spectrum revealed a shift in F2g peak with respect to that of Mg2Sn and Mg2Si in correspondence with the composition of the synthesised alloy. The synthesised alloy showed micro and nano hardness of 3.7 and 4.03 GPa respectively, which implies that good mechanical strength could be achieved in the synthesised alloy.

This module provides information about non-stainless martensitic steels; after a general introduction, discussion is made on chemical composition and properties of common grades of maraging steels. The strengthening mechanism in maraging steels is explained and following this, the factors affecting its toughness behavior are highlighted with special mention of the role of alloying elements on structure and properties of maraging steel. Similarly the composition and properties of medium carbon secondary hardening steels are presented. The strengthening mechanisms of AF1410 and similar steels are explained in details. Factors affecting toughness of this class of steel are also enumerated. Recent efforts on the development of new generation ultrahigh strength steels such as press hardenable steels and nanoscale precipitation strengthened ultrahigh strength high toughness steels are documented.

Demand of today is to optimize the available resources and reutilize the waste materials. Mill scale is waste cum byproduct obtained during hot rolling operation of steels.In Rajasthan there are hundreds of hot rolling mills producing tons of mill scale everyday and in Nagaur, Rajasthan there are huge reserves of low grade coal. In this paper an attempt has been made to utilize the low grade coal for direct reduction of mill scale in laboratory to obtain sponge iron .The paper comprises the study on effects of variation in particle size(60-100,170-200 and

This chapter discusses the heat treatment of some important commercial steels. It has enumerated the heat-treatment practices of the steels of commercial importance like low-carbon lean-alloy steels, medium-carbon high-alloy steels, structural steels, and ultra high-strength maraging steel. Elaborate discussion is made on the different varieties of stainless steels. Moreover the criticality of heat treatment of high-manganese austenitic steel is highlighted. Special care is given to analyze the practical problems of heat treating the above commercial steels in industrial situation. Besides discussion on the heat-treatment practices of the aforesaid steels, physical metallurgical principles underlying the design of the concerned heat-treatment cycles are also discussed to enable the readers to gain a deeper understanding about the subject.

ique in a high energy planetary ball mill. Systematic study on microstructural evolution and magnetic properties after different milling time is conducted by X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM) and Vibrating Sample Magnetometer (VSM). It is revealed that formation of single phase alloy with an average of ~ 7 nm crystallite size is achieved after 20 hr milling by mechanically induced inter-diffusion of atoms. Moreover, changes in lattice parameters and lattice strain as a function of milling time is also studied. Change in morphology of particles with increasing milling time has been studied by SEM. In addition, d-spacing and diffraction planes obtained from analysis of HRTEM image and SAD pattern respectively corroborate with XRD results. Low coercivity indicated by hysteresis loop is suggestive of soft ferromagnetic behavior of the alloy powder.

Fullerene C70 thins films of thickness ∼150 nm are prepared on quartz and glass substrates with thermal deposition technique. The films are irradiated with different ions (Au, Ag, Ni, Si) having different energies in order to vary the electronic energy loss (Se). The samples are also irradiated with range of fluence i.e. 1×1012 ions/cm2 to 3×1013 ions/cm2 for each energetic ion beam. The damage cross sections due to ion beam irradiation with different energetic ions (120 MeV Ag, 120 MeV Au, 90 MeV Ni, 55 MeV Si and 55 MeV Ni) are determined with Raman spectroscopy. A curve is plotted between electronic energy loss (Se) and damage cross section (σ) that is helpful to determine the damage cross section in fullerene C70 for any electronic energy loss. In addition, radius (r) of ion track can be approximated for any Se value from the constructed curve between r and Se.

The chapter has dealt with the fundamentals of heat treatment in reference to underlying physical metallurgy principles. Discussion has been initiated with description of the purpose of heat treatment of metals and alloys, the different stages of a heat treatment cycle, and the ways the different metals and alloys can be responsive to the process of heat treatment as a whole. Attention has been paid to enumerate the elements of heat treatment practice in a generalized fashion in order that the readers are able to identify the principles of heat treatment as generic to metals and alloys. Specificity is cited wherever it is required to make things clearer to the readers. Reference to steel is invoked to make it easy for the readers to grasp the underlying scientific principles which lead to changes in structure and property of materials undergoing heat treatment.

The chapter begins with introduction of different types of copper and copper alloys used in practice. Different types of heat treatments employed for the materials are listed and discussion on individual process, viz. homogenization, annealing after cold working is made. The effect of these heat treatments on changes in structure and properties and the reasons thereof are explained in detail. The stress relieving operation carried out with cold worked materials is also narrated. After discussing the generic issues, heat treatment of important alloys is individually narrated. Following this, the heat treatment of various bronzes is enumerated in detail. Besides these, the critical heat treatment of other copper alloys like chromium copper, zirconium copper, and chromium–zirconium–copper alloys are described with highlights of criticalities in heat treating these important alloys. Separately elaborate discussion is made of the different heat treatment of nickel alloys. Annealing, stress relieving, and cold work followed annealing of conventional nickel alloys are highlighted. That nickel alloyed with Al, Nb, Ti, and Si is capable of precipitation hardening is illustrated with specific examples. Data regarding heat treatment and the consequent properties of copper and nickel alloys are furnished in the form of tables. Due scientific explanations are provided where ever felt necessary.

This chapter starts with introduction of hardenability of steel. The critical cooling rate in respect of time-temperature transformation diagram or continuous cooling transformation diagrams is described to explain the hardenability in relation to martensite formation in steel. The effect of cooling rate on the formation of martensite and factors affecting cooling rate at different locations across the cross section of a steel object is elaborated. On the basis of this discussion the concept of critical diameter has been discussed. The Grossman method of determining critical diameter and its limitations are narrated. Jominy end quench test of hardenability measurement is explained in detail. Stating the limitation of critical diameter in understanding hardenability as a material property, the concept of ideal quenching and ideal critical diameter and a relation between them is established. Severity of quench and the quenching ability of different cooling media is explained with data. Having revealed that hardenability is the sole property of steel, the factors affecting hardenability is enumerated in greater details with proper scientific justification. Finally, quantitative determination of hardenability of steels from theoretical principles is demonstrated.

This module introduces tool and die steels including its general characteristics. The effect of alloying elements on the transformation behavior of austenite is discussed. Following this, the role of different alloying elements on hardenability and on tempering behavior of tool steels is enumerated; narrating the role of alloying elements on structure and properties of tool steels, the chemical composition and typical characteristics of different classes of tool steels are presented. Recent efforts on microstructural engineering to improve the fracture toughness of tool steels are illustrated. Further, researches in surface engineering for improving the performance of tool steels is mentioned; the impact of laser surface hardening on the performance of these steels is also highlighted.

This module introduces five important refractory metals. The physical properties along with the common characteristics of the concerned refractory metals are described. The manufacturing methods of the individual refractory metals and the constraints thereof are enumerated. The properties and uses of refractory metals under consideration are also discussed. Following this, various alloys of these refractory metals, their novel properties, and specific uses are elaborated. Pseudo softening and dynamic strain ageing in some dilute binary alloys are also recorded. A comparative analysis of strength and weakness of different alloys are presented.

In present investigation, the study of influence of strain rate and temperature on critical stress for initiation of dynamic re-crystallization in 0.05C-1.52Cu-1.51Mn steel is studied. It was observed that critical stress for initiation of Dynamic re-crystallization (DRX) is increases initially for lower strain rate and then it become saturated at higher strain rate. It is also found that materials exhibits typical dynamic re-crystallization behaviour at higher temperature and lower strain rate. It is due to the influence of thermal energy as DRX is a thermally activated process; also at lower strain rate more time is available for nucleation and growth of strain free crystals.