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Duck feathers are keratin-based natural fibres. After steaming, drying and milling, duck feather waste (DFW) was transformed into powder and incorporated in unsaturated polyester resin as reinforcing filler to fabricate composite panels. Particle sizes of the DFW powder were in the range of approximately 0.1–0.6 µm, with an average size of 0.21 ± 0.1 µm. Upon successful fabrication of duck feather waste (DFW) composites, different physical, thermal and mechanical investigations were carried out to evaluate their properties along with microscopic observations on fractured surfaces to unravel fracture mechanics. DFW powder was homogeneously distributed throughout the composite and showed hardness of approximately 46 HRC. Average flexural strength and tensile strength were about 24.51 ± 1.8 MPa and 9.27 ± 1.4 MPa respectively. Thermal analysis showed that the composite was stable up to about 250 °C, followed by slow degradation. The presently investigated DFW composite shows lower flexural strength, fatigue life and hardness than that of other natural fibre reinforced composites, as reported in the literature.

Nanoscale characterization (TEM on FIB-SEM-prepared foils) was undertaken on feldspars undergoing transformation from early post-magmatic (deuteric) to hydrothermal stages in granites hosting the Olympic Dam Cu-U-Au-Ag deposit, and from the Cu-Au skarn at Hillside within the same iron-oxide copper-gold (IOCG) province, South Australia. These include complex perthitic textures, anomalously Ba-, Fe-, or REE-rich compositions, and REE-flourocarbonate + molybdenite assemblages which pseudomorph pre-existing feldspars. Epitaxial orientations between cryptoperthite (magmatic), patch perthite (dueteric) and replacive albite (hydrothermal) within vein perthite support interface-mediated reactions between pre-existing alkali-feldspars and pervading fluid, irrespective of micro-scale crystal morphology. Such observations are consistent with a coupled dissolution-reprecipitation reaction mechanism, which assists in grain-scale element remobilization via the generation of transient interconnected microporosity. Micro-scale aggregates of hydrothermal hyalophane (Ba-rich K-feldspar), crystallizing within previously albitized areas of andesine, reveal a complex assemblage of calc-silicate, As-bearing fluorapatite and Fe oxides along reaction boundaries in the enclosing albite-sericite assemblage typical of deuteric alteration. Such inclusions are good REE repositories and their presence supports REE remobilization at the grain-scale during early hydrothermal alteration. Iron-metasomatism is recognized by nanoscale maghemite inclusions within ‘red-stained’ orthoclase, as well as by hematite in REE-fluorocarbonates, which reflect broader-scale zonation patterns typical for IOCG systems. Potassium-feldspar from the contact between alkali-granite and skarn at Hillside is characterized by 100–1000 ppm REE, attributable to pervasive nanoscale inclusions of calc-silicates, concentrated along microfractures, or pore-attached. Feldspar replacement by REE-fluorcarbonates at Olympic Dam and nanoscale calc-silicate inclusions in feldspar at Hillside are both strong evidence for the role of feldspars in concentrating REE during intense metasomatism. Differences in mineralogical expression are due to the availability of associated elements. Lattice-scale intergrowths of assemblages indicative of Fe-metasomatism, REE-enrichment and sulfide deposition at Olympic Dam are evidence for a spatial and temporal relationship between these processes.

The mechanical properties and deformation behaviour of a selective laser melted (SLMed) Ti6Al4V alloy were investigated at the micro-scale via in situ micro-pillar compression. The microstructure of the alloy consists of acicular martensite (α′) compared to the bi-modal α/β microstructure of a mill-annealed alloy of similar composition. This microstructure, together with loading direction with respect to build direction, affects the mechanical properties and gives rise to anisotropy. Irrespective of build orientation, both the yield and the ultimate compressive strength of the alloy is about 1.8 times more than that of the mill-annealed alloy. The rise of anisotropy was related to the presence of prior β grain orientation with that of the loading direction and is discussed in relation to predominant fracture mechanisms. TEM investigation on the deformed micropillars showed the existence of a vast network of dislocations, stacking faults and compression twinning { 10 1 ‾ 2 } ; which was identified as a load accommodation mechanism during deformation.

This paper investigates comprehensive knowledge regarding joining CFRP and aluminium alloys in available literature in terms of available methods, bonding processing and mechanism and properties. The methods employed comprise the use of adhesive, self-piercing rivet, bolt, clinching and welding to join only CFRP and aluminium alloys. The non-thermal joining methods received great attention though the welding process has high potential in joining these materials. Except adhesive bonding and welding, other joining methods require the penetration of metallic pins through joining parts and therefore, surface preparation is unimportant. No model is found to predict the properties of jointed structures, which makes it difficult to select one over another in applications. The choice of bonding methods depends primarily on the specific applications. The load-bearing mechanism of bolted joints is predominantly the friction that is the first stage resistance. Hybrid joints performance is enhanced by combining rivets, clinch or bolts with adhesives. Refereed/Peer-reviewed

Regular degradation of rubbers contribute frequent maintenance of conveyer belt system. This paper investigates wear rate and mechanisms of rubber and associated influential parameters based on the information available in literature. Abrasion, fatigue and roll formation are dominate wear mechanisms that are influenced by load, sliding velocity, hardness and friction. Correlations among influential parameters and their effect on rubber wear was established in details. Archad's equation does not work for rubber wear but researchers have proposed equations similar to that. Adhesion wear forms roll in the smooth surface when tear strength of rubber is low. Wear caused by adhesion is abrasion when surface texture is harsh. Hysteresis enhances fatigue wear if the substrate asperities are round or blunt.

Rubbers are polymer materials characterized by the ability of reversible deformation under influence of external deformation forces, described as a material with elastic properties. Rubbers include natural rubber, naturally occurring substance and synthetic rubber, artificially derived from petrochemical product. Products made from rubber have flexible and stable 3-dimensional chemical structure and the ability to stretch repeatedly of about twice the original length and return to original length. These materials are enormously used in conveyer belt system. Today, rubber materials are altered with approximately 60% synthetic polymers to achieve desired properties of final product. This chapter investigates the wear of different types of rubbers against ceramic liners which is the most realistic case in mining industries, where conveyor belts are used for ore transportation pulleys in conveyer belt system are coated with sacrificial liners of ceramics and rubbers to prolong the life of the conveyor system. However, such pulley liners are exposed to wear and even chemical reactions particularly in mining industries that are involved in transporting ores. The investigation will provide information on surface in terms of wear mechanism of rubber against ceramics, wear rate and appearance of wear surfaces.

The influence of contents, sizes and shapes of reinforcements on the matrix-particle interfaces in terms of (a) von-Mises stress, (b) directions as well as spreading of principal stresses during cooling and under tension were analysed in this investigation through numerical simulation for SiC particle reinforced Al6061 matrix MMCs. The result shows that the rapid variation of von-Mises stress in the interfaces depends on the shape of reinforced particles. The interfaces in MMCs with triangular reinforcements experienced the slimiest stress variation. Nevertheless, the uppermost stress was intensified in the corners of the triangle shaped reinforcements. The shape of the reinforcements affects the stress vectors directions. The range of the von-Mises stress rises through the rise of particle amount and decrease of particles size at a constant number of particles. For nearly all the cases, excluding the MMCs with triangle reinforcements, when the stress rises, with the rise of the applied positive elongation, the stress scatterings are unaffected.

Most of the Automatic Test Pattern Generation (ATPG) algorithms for digital circuits rely heavily on netlist description that comprises both network interconnect structure among logic gates and the functionality of each gate. The performance of an ATPG tool on a circuit-under-test (CUT) C is determined by the size of the test set T and its fault coverage (FC). Despite extensive research in the field of testing, the following question remains unanswered: Is the structure or the functionality of C dominant in determining FC of a test-set T for C? In this paper, we present empirical evidence in favour of the dominance of structure on FC by randomly selecting a logic gate from a synthesized netlist for C, and replacing it by a different type of gate. Our experiments provide an un-intuitive result that F C of a test-set T for C under the single stuck-at fault model remains nearly the same on other sibling circuits that have identical structure as of C but with different gate functionality, provided these have similar extent of fault redundancy. This observation supports the view that feeding structural information alone may suffice to train machine-learning models that are currently being used to expedite different problems of digital circuit testing and diagnosis.

A Monte Carlo (MC) simulation study of cosmic ray (CR) extensive air showers (EAS) has been carried out in the energy regime of the KASCADE experiment. From the characteristics of lateral distributions of electrons and muons of simulated EAS, some important EAS observables are extracted by a novel approach, and their CR mass-sensitivity is demonstrated. The study takes into account the issue of the experimental lateral density profiles of EAS electrons and muons after introducing the notion of the local age and segmented slope parameters, aimed to extract information on CR mass composition from observed data. The estimated lateral shower age and slope from the analysis of the KASCADE data (KCDC) agrees with the idea of a gradual change of CR mass composition from light to heavy around the knee., 8 pages, 10 figures, Accepted in a Journal

This chapter presents analysis and optimization of machinability of Mild steel grade 350 while high speed drilling operation. Taguchi design of experiments (DoEs), analysis of variance (ANOVA) and other traditional methods were applied to optimize the input variables in order to minimise the circularity, cylindricity, diameter error and surface roughness of drilled holes. It was found that point angle was the highest contributor for the circularity, cylindricity and surface roughness of drilled holes. The circularity error was minimum at the low speed (584 rpm), low feed (0.15 mm/rev) and moderate point angle (125°). The cylindricity error of holes was minimised at the high speed (849 rpm), moderate feed (0.2 mm/rev) and moderate point angle (125°). The moderate speed, low feed and moderate point angle minimised surface roughness considerably. The interaction between speed and point angle had the maximum contribution to the diameter error of drilled holes. The diameter error was minimum at the moderate speed, low feed and moderate point angle.

Non-conventional machining process for instance, wire electrical discharge machining (WEDM) of titanium alloys is gaining attention due to non-contact nature of this process. To deepen the understanding in this area, this study investigates surface generation, kerf width, discharge gap, material removal rate and wire degradation during WEDM of Ti6Al4V alloy. Pulse on time (4–10 μs), flushing pressure (7–18 MPa) and wire tension (800–1700 gf) were varied and resulting influences on output parameters were analysed. It was found that, machined surfaces consist of multi-layered recast layer with the presence of cracks, holes as well as traces of materials from electrode wire. The composition and roughness of the machined surface varies slightly with respect to machining condition without following any trend. In addition, deformation and morphology of deformed wire electrode after the WEDM process was also reported in this study.

With the lightning speed of technological evolution, the demand for high performance yet sustainable natural fibres reinforced polymer composites (NFPCs) are rising. Especially a mechanically competent NFPCs under various loading conditions are growing day by day. However, the polymers mechanical properties are strain-rate dependent due to their viscoelastic nature. Especially for natural fibre reinforced polymer composites (NFPCs) which the involvement of filler has caused rather complex failure mechanisms under different strain rates. Moreover, some uneven micro-sized natural fibres such as bagasse, coir and wood were found often resulting in micro-cracks and voids formation in composites. This paper provides an overview of recent research on the mechanical properties of NFPCs under various loading conditions-different form (tensile, compression, bending) and different strain rates. The literature on characterisation techniques toward different strain rates, composite failure behaviours and current challenges are summarised which have led to the notion of future study trend. The strength of NFPCs is generally found grow proportionally with the strain rate up to a certain degree depending on the fibre-matrix stress-transfer efficiency. The failure modes such as embrittlement and fibre-matrix debonding were often encountered at higher strain rates. The natural filler properties, amount, sizes and polymer matrix types are found to be few key factors affecting the performances of composites under various strain rates whereby optimally adjust these factors could maximise the fibre-matrix stress-transfer efficiency and led to performance increases under various loading strain rates.

Higher tool wear and inferior surface quality of the specimens during machining restrict metal matrix composites’ application in many areas in spite of their excellent properties. The researches in this field are not well organized, and knowledge is not properly linked to give a complete overview. Thus, it is hard to implement it in practical fields. To address this issue, this article reviews tool wear and surface generation and latest developments in machining of metal matrix composites. This will provide an insight and scientific overview in this field which will facilitate the implementation of the obtained knowledge in the practical fields. It was noted that the hard reinforcements initially start abrasive wear on the cutting tool. The abrasion exposes new cutting tool surface, which initiates adhesion of matrix material to the cutting tool and thus causes adhesion wear. Built-up edges also generate at lower cutting speeds. Although different types of coating improve tool life, only diamond cutting tools show considerably longer tool life. The application of the coolants improves tool life reasonably at higher cutting speed. Pits, voids, microcracks and fractured reinforcements are common in the machined metal matrix composite surface. These are due to ploughing, indentation and dislodgement of particles from the matrix due to tool–particle interactions. Furthermore, compressive residual stress is caused by the particles’ indentation in the machined surface. At high feeds, the feed rate controls the surface roughness of the metal matrix composite; although at low feeds, it was controlled by the particle fracture or pull out. The coarser reinforced particles and lower volume fraction enhance microhardness variations beneath the machined surface.

Electric discharge machining has been established as an effective alternative process to conventional material removal processes for machining reinforced metal matrix composites. Wire cut electric discharge machining holes were produced in a metal matrix composite (10 vol% of SiC in Al6061), which were then investigated to determine the machinability of the material using this process. It was observed that the input factors such as the size of reinforced particles, wire tension and pulse-on time significantly affect diameter error, circularity and surface roughness. Pulse-on time, the interaction between pulse-on time and wire tension contribute to the maximum diameter error. The wire tension is the most significant factor to circularity, which is followed by the interaction between pulse-on time. In particular, wire tension with low and high tensions results in poor circularity. It has been found that there are more surface defects encountered when particle sizes are smaller, and circularity is improved when particles are in a medium size. In addition, the surface defect is reduced as the particles increase the melting resistance of the surface. The higher pulse-on time leads to higher heat and more time to degrade the surface. Therefore, low pulse-on time and wire tension gave better surface finish.

The effects of machining parameters, such as reinforcement size, machining speed and feed rate, on tensile strength, strain at break and fractured surfaces of Al-based metal matrix composites were analysed in this present investigation. It was found that larger particles (13 µm) induce higher stiffness on machined metal matrix composite parts machined at higher speed (2500 r/min) and lower feed (200 mm/min), providing constant input parameters are of low values and vice versa. The effect of reinforcement size on tensile strength is negligible and higher speed (2500 r/min) and lower feed (200 mm/min) give higher tensile strength when constant input parameters are of low values. The higher machining speed (2500 r/min) gives higher strain at break though reinforcement size and feed rate have minor effect on strain at break when the constant input parameters are of high values. When the constant input parameters are of low values, the smaller reinforcement (0.7 µm), machining speed (1500 r/min) and feed rate (200 mm/min) give higher strain at break. Ductile fracture occurs in all cases regardless of input variables and smaller nodules were formed on fractured surface in the case of smaller particle (0.7 µm)-reinforced metal matrix composites.

Project-based learning process is nearer to the professional realism, and thus, requires lengthier period to imbibe compared to problem-based education activities. In addition, project-based learning requires application of knowledge and usually is accompanied by core subjects (e.g., maths, physics) and stronger self-direction. Therefore, students require to commit overall time management and resources. By taking consideration of above-mentioned facts, this chapter discusses the introduction of project-based manufacturing process unit which is essential for the bachelor degree course in Mechanical Engineering at Curtin University. The project was about manufacturing a hammer that cover basic manufacturing processes, such as production planning, conventional shaping and machining, computer numerical control (CNC) machining, etc. The students were required to hand-hammer drawing and step-by-step manufacturing process over the semester and discuss with the faculties in regular time interval. Finally, students’ feedbacks were recorded and analyzed. It was found that introduction of project-oriented learning improved students’ satisfaction as well as interest to learn. This change, as made in 2012, improved overall student satisfaction rate by 9% with an increasing trend.

This study analyzes the femoral neck in an artificial hip joint and explores design variations using finite element analysis to compile an optimum design. An effective prosthesis should have minimal stress concentration and deformation as well as versatility to handle different loads applied at various angles. Different femoral neck designs were modeled using Ti-6Al-4V alloy material with the following loads; 1962, 2354.4, 2746.8 and 3139.2 N, and applied at angles of 35, 45, 55, and 65 degrees. The minimum stress concentrations, deformation, and stress distribution were analyzed and compared while varying the boundary conditions. The final design was selected based on the analysis of which was the most effective and versatile design, consisting of a straight-edged profile and trapezoidal cross-section.

As an alternative to conventional Pb-containing solder material, Sn–Ag–Cu (SAC) based alloys are at the forefront despite limitations associated with relatively poor strength and coarsening of grains/intermetallic compounds (IMCs) during aging/reflow. Accordingly, this study examines the improvement of properties of SAC alloys by incorporating nanoparticles in it. Two different types of nanoparticles were added in monolithic SAC alloy: (1) Al2O3 or (2) Fe and their effect on microstructure and thermal properties were investigated. Addition of Fe nanoparticles leads to the formation of FeSn2 IMCs alongside Ag3Sn and Cu6Sn5 from monolithic SAC alloy. Addition of Al2O3 nano-particles do not contribute to phase formation, however, remains dispersed along primary β-Sn grain boundaries and act as a grain refiner. As the addition of either Fe or Al2O3 nano-particles do not make any significant effect on thermal behavior, these reinforced nanocomposites are foreseen to provide better mechanical characteristics with respect to conventional monolithic SAC solder alloys.

This study investigated the face milling of nanoparticles reinforced Al-based metal matrix composites (nano-MMCs) using a single insert milling tool. The effects of feed and speed on machined surfaces in terms of surface roughness, surface profile, surface appearance, chip surface, chip ratio, machining forces, and force signals were analyzed. It was found that surface roughness of machined surfaces increased with the increase of feed up to the speed of 60 mm/min. However, at the higher speed (100–140 mm/min), the variation of surface roughness was minor with the increase of feed. The machined surfaces contained the marks of cutting tools, lobes of material flow in layers, pits and craters. The chip ratio increased with the increase of feed at all speeds. The top chip surfaces were full of wrinkles in all cases, though the bottom surfaces carried the evidence of friction, adhesion, and deformed material layers. The effect of feed on machining forces was evident at all speeds. The machining speed was found not to affect machining forces noticeably at a lower feed, but those decreased with the increase of speed for the high feed scenario.

This paper investigated the degradation of wire electrode during electrical discharge machining of SiC reinforced Al-based metal matrix composites (MMCs). MMCs with different size of reinforcements (0.7, 3 and 13 µm) as well as corresponding matrix material were machined under similar machining conditions to understand the effect of reinforcement size on the degradation of wire. In addition, pulse-on-time and wire tension were varied to understand the effect of machining parameters and interaction between machining parameters and size of the reinforcements. It was found that initial circular shaped wire deformed during the machining process as curved front and rear edges and two straight side edges irrespective of cutting conditions and workpiece materials. The curved edge at the front and straight side edges take part in material removal and experience sever degradations. The final cross-sectional area of the wire after the machining process is decided by balancing two mechanisms: (i) downward flow of highly malleable soft wire material due to high temperature which increases the diameter of wire electrode and (ii) vaporisation of the wire material at higher temperature which reduces the diameter of wire electrode. These complex processes are affected by machining conditions as well as workpiece materials.

Duplex surface treatment, that is, chromizing and plasma nitriding (PN) of steels have attracted interest from industrial sectors because of its attractive properties and ability to apply on different types of steels. This paper aims to investigate duplex treatment on different types of steels at different treatment conditions. The improvements of the treated surfaces in terms of morphology and thickness, composition, surface hardness and roughness, as well as wear and friction of the engineered layer have been analysed. It was found that several layers of different thickness are formed due to duplex treatment which depends on the specimen’s carbon content and treatment temperature. Mainly carbides and nitrides of chromium and iron are formed, where the amount and composition of them are controlled by duplex treatment process parameters. These compounds enhance the hardness and wear resistance of the treated surface. The CrxN phase is the main contributor towards high microhardness of duplex-treated layer...

The wire electrical discharge machining (EDM) of 6061 aluminium alloy in terms of material removal rate, kerf/slit width, surface finish and wear of electrode wire for different pulse on time and wire tension was studied. Eight experiments were carried out in a wire EDM machine by varying pulse on time and wire tension. It is found that the material removal rate increases with the increase of pulse on time though the wire tension does not affect the material removal rate. It seems that the higher wire tension facilitates steady machining process, which generates low wear in wire electrode and better surface finish. The surface roughness does not change notably with the variation of pulse on time. The appearance of the machined surfaces is very similar under all the machining conditions. The machined surface contains solidified molten material, splash of materials and blisters. The increase of the pulse on time increases the wear of wire electrode due to the increase of heat input. The wear of wire electrode generates tapered slot which has higher kerf width at top side than that at bottom side. The higher electrode wear introduces higher taper.

Gluconate plating baths were successfully used for the synthesis of homogenous, crack-free nanostructured gradient Co-Sn coatings. The grain size of electrodeposited Co-Sn sub-layers was found by X-ray Diffraction to range from 10 up to 143 nm, whereas the increase of Sn content into the Co-Sn sub-layers led to an increase of average grain size. The average hardness of the gradient coating was found to be significantly higher than that of the pure Sn electrocoating, due to the presence of intermetallic phases. In addition, the frictional properties of the Co-Sn gradient coatings strongly depend on the thickness of the pure Sn top layer, as the thin top layer can shear when sliding against the counterface material. On the other hand, thick Sn layers as in the case of pure Sn electrodeposits result in a higher coefficient of friction of the tribosystem due to adhesive wear phenomena, brought about by the formation of debris at the sliding contact. Furthermore, nanostructured gradient Co-Sn coatings are found to have significantly higher wear resistance when compared to pure Sn coatings. The main wear mechanisms observed were adhesive and abrasive wear of the Sn top layers and subsequent deformation and cracking of the intermetallic based Co-Sn sub-layers.

Duplex stainless steels (DSSs) have many advantages due to the unique structural combination of ferrite and austenite grains. The structural change of these materials is very complex during welding, and it deteriorates the functional properties. This research investigates different welding processes such as laser beam, resistance, tungsten inert gas, friction stir, submerged arc, and plasma arc weldings considering the research available in the literature. The welding mechanism, change of material structure, and control parameters have been analyzed for every welding process. This analysis clearly shows that DSS melts in all most all welding processes, but the thermal cycle and maximum heat input are different. This difference affects the resulting structure and functional properties of the weld significantly.

Symplectites comprising clausthalite (PbSe) and host Cu-(Fe)-sulphides (chalcocite, bornite, and chalcopyrite) are instructive for constraining the genesis of Cu-Au-(U) ores if adequately addressed at the nanoscale. The present study is carried out on samples representative of all three Cu-(Fe)-sulphides displaying clausthalite inclusions that vary in size, from a few µm down to the nm-scale ( 265 °C. A minimum temperature of 165 °C is considered for clausthalite-bearing symplectites from the relationships with antiphase boundaries in 6a digenite. The results show that alongside rods, blebs, and needle-like grains of clausthalite within the chalcocite that likely formed via exsolution, a second, overprinting set of replacement textures, extending down to the nanoscale, occurs and affects the primary symplectites. In addition, other reactions between pre-existing Se, present in solid solution within the Cu-(Fe)-sulphides, and Pb, transported within a fluid phase, account for the formation of composite, commonly pore-attached PbSe and Bi-bearing nanoparticles within the chalcopyrite. The inferred reorganisation of PbSe nanoparticles into larger tetragonal superlattices represents a link between the solid solution and the symplectite formation and represents the first such example in natural materials. Epitaxial growth between clausthalite and monazite is further evidence for the interaction between pre-existing Cu ores and fluids carrying REE, P, and most likely Pb. In U-bearing ores, such Pb can form via decay of uranium within the ore, implying hydrothermal activity after the initial ore deposition. The U-Pb ages obtained for such ores therefore need to be carefully assessed as to whether they represent primary ore deposition or, more likely, an overprinting event. A latest phase of fluid infiltration is the recognised formation of Cu-selenide bellidoite (Cu2Se), as well as Fe oxides.

This study aims to investigate the fundamental deformation mechanism of Ti-based bulk metallic glass under mechanical loading by a cutting tip. The cutting tip interaction is resolved into two separate actions, namely nanoindentation by using a Berkovich diamond indenter and contact sliding under a pin-on-disk configuration. The deformation details in the specimens due to the action of the corresponding mechanical loading were analyzed by SEM and TEM. It was found that under nanoindentation, the plastic deformation is evidenced by a series of pop-ins in load–displacement graphs. The temperature rise at the contact interface during sliding must have been above the glass transition temperature and the onset temperature of crystallization, leading to the formation of discrete nanocrystalline particles in the immediate subsurface and hence bringing about an increase in hardness of the metallic glass in the wear tracks.

EXO 2030+375" is a well-known binary system showing periodic outburst. The spectral analysis on the system during the outburst helps us to know more about the origin as well as material present within the system. In this work, we have considered one such outburst data obtained using Suzaku X-Ray mission having very good imaging as well as energy resolution capabilities. Following the stepwise algorithm of the Suzaku analysis guide, we have applied the various computational modules for pre-processing as well as data reduction. After that, we have used the ftools, a specialized computational package for analysis of X-ray data obtained from various X-Ray missions. The data analysis helped us to understand the origin as well as given an insight of the material present within the system.

The effect of pulse on time, pulse off time and wire tension were investigated on the fatigue life, crack propagation, surface roughness and machining feed during wire EDM of Ti-6Al-4V alloy. The fatigue performance of all samples is very similar at higher cyclic loading. The machining conditions affected the lower cyclic loading. Lower pulse-on time and higher pulse-off time gave the longest life at lower cyclic loading. The higher wire tension gave shorter life and then remained almost constant at lower tension. It seems that the recast layer and heat affected zone are the main contributor to the fatigue performance.

This study investigates the deformation of Al-based metal matric composites (MMCs) under in-situ micro-pillar compression. Different sizes of SiC nanoparticles, namely 55 nm and 700 nm, were used as reinforcing medium in the MMCs. Such in-situ compression shows real time deformation of materials and helps to correlate materials’ response with corresponding stress-strain curves. It was shown that, MMCs exhibit higher yield strength compared to monolithic Al, thanks to effective load bearing among reinforcement and matrix. Whereas monolithic Al experience substantial work hardening, MMCs experience blocking of dislocations and slip/shear bands by the presence of reinforcing nanoparticle. These gives rise superior strength on MMCs compared to monolithic Al6061 alloy, which is about two times higher.

Alumina dispersed FeCuAl-based nanostructured cermet coatings were deposited from nanostructured powders by atmospheric plasma spraying on low carbon steel substrates. Nanostructuring was retained in the deposited coatings which exhibit up to four distinctive phases as revealed by electron microscopy. In this study, the friction behavior of the distinctive phases at nano-normal load scale was investigated alongside their contribution to the overall friction behavior at macro-normal load scale. Friction behavior at nano-normal load scale was investigated by lateral force microscopy, whereas conventional tribometers were used for investigations at micro and macro-normal loads. It appeared that, the friction measured at nano-normal loads on individual phases is dictated by both composition and hardness of the corresponding phases, and thus influences the overall friction behavior of the coatings at macronormal loads. Moreover, the coefficient of friction at macro-normal loads differs from the one at nano-normal loads, and deviates from Amonton’s friction law. ispartof: Metallurgical and Materials Transactions A, Physical Metallurgy and Materials Science vol:45 issue:2 pages:1049-1056 status: published

The quest for the advanced functional material of superior functionality for advanced structure is being driven in various fronts of engineering materials. One of such front is metal matrix composite (MMC) which has already been proven as one of the most productive field in that respect. With the advance of technology, now it is possible to reinforce the MMCs with nanosized particles compared to conventional micron-sized ones. However, the addition of nanoparticle in the MMC to improve its mechanical properties is not unconditional. To achieve positive gain by adding nanoparticles in the MMCs, all the influencing factors should be taken into consideration. The present paper reviews the failure mechanisms of nanoparticles reinforced MMCs in light of its strengthening mechanisms.

This paper describes the development of an off-line feed rate scheduling technique based on a mechanistic cutting force model. The proposed technique was developed for an end milling operation. The surface area of the workpiece was divided into a number of segments, and the resultant cutting force at each discrete segment was determined using One Path Analysis software. The calculated resultant cutting force was applied to the feed rate scheduling. Experimental results clearly showed that the implementation of feed rate scheduling reduces machining time considerably and that as the number of segments increases, the effectiveness of the feed rate scheduling increases.

This paper establishes the first quantitative relationship between the phases transformed in silicon and the shape characteristics of nanoindentation curves. Based on an integrated analysis using TEM and unit cell properties of phases, the volumes of the phases emerged in a nanoindentation are formulated as a function of pop-out size and depth of nanoindentation impression. This simple formula enables a fast, accurate and quantitative prediction of the phases in a nanoindentation cycle, which has been impossible before.

Over the past couple of decades, nanocrystalline materials, commonly noted as nanomaterials, are receiving wide attention among scientists due to unusual material properties at the nanoscale that are not foreseen in the micro-/macroscale. This field of nanomaterials is still very young, requires a long quest, and upholds prospects beyond imagination. With this in view, this chapter compiles the advancements of magnetic behaviors of such nanomaterials. Starting from the origin of magnetism in nanomaterials, we have systematically addressed their functionality, fabrication, and characteristics. This chapter ends with concluding remarks and the future prospects of magnetic nanomaterials.

As is recognized widely, tool wear is a major problem in the machining of difficult-to-cut titanium alloys. Therefore, it is of significant interest and importance to understand and determine quantitatively and qualitatively tool wear evolution and the underlying wear mechanisms. The main aim of this paper is to investigate and analyse wear, wear mechanisms and surface and chip generation of uncoated and TiAlN-coated carbide tools in a dry milling of Ti6Al4V alloys. The quantitative flank wear and roughness were measured and recorded. Optical and scanning electron microscopy (SEM) observations of the tool cutting edge, machined surface and chips were conducted. The results show that the TiAlN-coated tool exhibits an approximately 44% longer tool life than the uncoated tool at a cutting distance of 16 m. A more regular progressive abrasion between the flank face of the tool and the workpiece is found to be the underlying wear mechanism. The TiAlN-coated tool generates a smooth machined surface with 31% lower roughness than the uncoated tool. As is expected, both tools generate serrated chips. However, the burnt chips with blue color are noticed for the uncoated tool as the cutting continues further. The results are shown to be consistent with observation of other researchers, and further imply that coated tools with appropriate combinations of cutting parameters would be able to increase the tool life in cutting of titanium alloys. Refereed/Peer-reviewed

A correlation between machining process and fatigue strength of machined components clearly exists. However, a complete picture of the knowledge on this is not readily available for practical applications. This study addresses this issue by investigating the effects of machining methods on fatigue life of commonly used materials, such as titanium alloys, steel, aluminium alloys and nickel alloys from previous literature. Effects of turning, milling, grinding and different non-conventional machining processes on fatigue strength of above-mentioned materials have been investigated in detail with correlated information. It is found that the effect of materials is not significant except steel in which phase change causes volume expansion, resulting in compressive/tensile residual stresses based on the amounts of white layers. It is very complex to identify the influence of surface roughness on the fatigue strength of machined components in the presence of residual stresses. The polishing process improves the surface roughness, but removes the surface layers that contain compressive residual stresses to decrease the fatigue strength of polished specimens. The compressive and tensile residual stresses improve and reduce fatigue strength, respectively. Grinding process induces tensile residual stresses on the machined surfaces due to high temperature generation. On the other hand, milling and turning processes induce compressive residual stresses. High temperature non-conventional machining generates a network of micro-cracks on the surfaces in addition to tensile residual stresses to subsequently reduce fatigue strength of machined components. Embedded grits of abrasive water jet machining degrade the fatigue performance of components machined by this method. Refereed/Peer-reviewed

The high cycle constant stress amplitude fatigue performance of metal matrix composite (MMC) components machined by a milling process was investigated in this study as a function of machining speed, feed rate and reinforcement particle size. The presence of reinforcement and particle size were found to be the most influential factors that affected the fatigue life. In contrast to this, the effect of feed and speed on tool-particle interaction, strain hardening and heat generation during milling of MMCs were balanced in such a way that the contributions of feed and speed on fatigue life were negligible. The interactions of different parameters contributed significantly to the fatigue life which indicated that the modelling of fatigue life based on these three parameters was relatively complex. The fatigue life of the machined MMC samples increased with decreasing particle size and increasing feed. However, the fatigue life was not influenced by speed variation. The presence of smaller or no particles induced a complete separation of failed samples, in contrast to that of specimens containing larger reinforcing particles where crack growth was arrested or deflected by the reinforcing particles. Refereed/Peer-reviewed

Electroless-nickel (EN) and very few other materials are suitable for ultra-precision machining. This material exhibits excellent properties such as hardness, corrosion resistance which are essential for molding die. This paper discusses the properties of EN and links with the ultra-precision machinability of this material. It is found that chip formation processes changes with the cutting condition. Phosphorus content and heat treatments significantly affect the machinability of EN in terms of tool wear, machining force and surface finish.

This paper aims to investigate the mechanism of ductile machining of brittle material based on information available in the literature. It also explores the challenges associated with the ductile machining of brittle materials which stop the technology from being applied in practical fields. In addition, few factors that assist to improve productivity of ductile machining of brittle material have been discussed. It is found the higher tool wear is the main obstacle of this technology. The application ofmicro-laser heating,ultrasonic vibration and coolants improve the machining time and tool life significantly.

This paper investigates the machining mechanism of titanium alloys and analyses those understandings systematically to give a solid understanding with latest developments on machining of titanium alloys. The chip formation mechanism and wear of different cutting tools have been analyzed thoroughly based on the available literature. It is found that the deformation mechanism during machining of titanium alloys is complex and it takes place through several processes. Abrasion, attrition, diffusion–dissolution, thermal crack and plastic deformation are main tool wear mechanisms.

Nanostructured WC–Co and WC–Co–Al coatings, with about 300-μm as-deposited coating thickness, were deposited by high velocity oxy-fuel (HVOF) spraying. Agglomerated nanostructured cermet powders produced by the Mechanomade® process was used for HVOF spraying. Dense and well-adherent coatings with crystal sizes below 30 nm were deposited on stainless steel 304 substrate. Porosity was less than 5% and the bond strength with the substrate was around 60 MPa. Experimental data on friction, wear, and abrasion resistance revealed that nanostructured WC–Co based coatings containing some Al as alloying element, exhibit improved tribological characteristics in comparison to nanostructured and micron-sized WC–Co coatings. This was attributed to a carbide particle distribution within the coating revealed by SEM, the absence of brittle W 2 C-like phases revealed by XRD, and the presence of Al at particle/matrix boundaries revealed by TEM.

This paper investigates the effect of high loads (up to100 N) and high speeds (up to 3 m/s) on wear and friction behaviour of PVD deposited CrN coatings on cast iron substrate. Uncoated substrate materials were also tests under identical test parameters to compare the friction coefficient, wear rate, temperature generation accompanied with wear mechanism. With the increase of normal loads from 50 N to 80 N the wear rate of coated sample increases from 4.59 × 10−5 mm3/Nm to 6.86 × 10−5 mm3/Nm, while the sliding speed remains constant. Temperature rise due to friction was monitored in wear tracks, and higher wear track temperature (from 65°C to 178°C) simulates higher coating wear as well as degradation of materials. The wear mechanisms of the CrN coatings involve pull out of nitride particles, oxidation of wear particles, adhesive wear and a combination of fatigue delamination as evident from wear track morphology investigated by scanning electron microscope.

This paper investigates the effect of SAE grade 20W50 engine oil as a lubricant on the wear behaviour of chromium nitride (CrN) coating deposited by PVD process at higher loads and speeds by pin on disc tribometer. The specific wear rate ranges from 9.82 × 10-5 to 2.87 × 10-5 mm3/Nm in dry condition whereas in lubricated condition 0.97 × 10-5 to 0.19 × 10-5 mm3/Nm. Successive increase of speed and load rises the temperature of wear track from 65°C to 178°C in dry condition while 34°C to 40°C in lubricated conditions results to decrease in friction coefficient, which has immense influence on the wear resistance of coating. The wear mechanism of the coatings was analysed by SEM and EDS and found deformation, cracks and, nitride particle pull-out, built up edge formation, erosion and adhesive wear coupled with oxidation wear. The highlights of the paper are: 1) tribology of CrN coating against cylinder liner material as counter face summarised; 2) research has practical applications for piston ring with the influence of engine oil; 3) temperature ranges from 65°C to 178°C in dry and 34°C to 39°C in lubrication during wear test; 4) the wear mechanism is combination of three body abrasion, metal transfer and oxidation.

Hole quality in drilling is considered a precursor for reliable and secure component assembly, ensuring product integrity and functioning service life. This paper aims to evaluate the influence of the key process parameters on drilling performance. A series of drilling tests with new TiN-coated high speed steel (HSS) bits are performed, while thrust force and torque are measured with the aid of an in-house built force dynamometer. The effect of process mechanics on hole quality, e.g., dimensional accuracy, burr formation, surface finish, is evaluated in relation to drill-bit wear and chip formation mechanism. Experimental results indicate that the feedrate which dictates the uncut chip thickness and material removal rate is the most dominant factor, significantly impacting force and hole quality. For a given spindle speed range, maximum increase of axial force and torque is 44.94% and 47.65%, respectively, when feedrate increases from 0.04 mm/rev to 0.08 mm/rev. Stable, jerk-free cutting at feedrate of as low as 0.04 mm/rev is shown to result in hole dimensional error of less than 2%. A low feedrate along with high spindle speed may be preferred. The underlying tool wear mechanism and progression needs to be taken into account when drilling a large number of holes. The findings of the paper clearly signify the importance and choice of drilling parameters and provide guidelines for manufacturing industries to enhance a part&rsquo, s dimensional integrity and productivity.

Abrasive jet micromachining is a novel non-conventional machining process with applications in the opto-electrical and semiconductor industries. To understand the process, it is important to investigate the material removal mechanisms starting from a single particle impact. Different types of impressions or erosions produced by single particle impact on monocrystalline silicon and the effect of erosion parameters are presented and discussed. It is found that particle velocity, particle size and erosion angle all play an important role in the material removal process. Three types of impressions are broadly identified which include craters, scratches and microdents. Among these types of impressions, craters with brittle cleavage fractures cause instant material removal by crushing upon micro-particle impact. On the other hand, scratches are mainly responsible for crack network formation, which decreases material strength. The radial and lateral crack networks, which cause material spalling, are present in both surface and sub-surface region as shown by electron microscopy investigation. A transmission electron microscopy study shows the retention of crystalline structure below the crater impressions. It is also found that increasing the particle velocity, particle size and erosion angle increases the formation of crater-type impressions.

The feasibility of achieving a nanostructured material after different thermal processing of nanosized powders is presented. The thermal processing was done by either atmospheric plasma spraying, laser sintering, or extrusion followed by hot isostatic pressing. The structural characterisation of such thermally processed nanostructured Fe-based and Cu-based metallic or Al2O3 reinforced cermets, confirmed the retention of a nanostructure after each of these thermal processes. Hardness measurements confirmed an increased hardness as expected in the case that nanostructuring is achieved. The role of grain boundaries and second phase particles on the retention of the nanostructure after thermal processing is discussed. Finally, the possible benefit of nanostructuring on the friction and wear behaviour of materials in sliding tests against corundum in ambient air is reported and discussed.

The chemical reactivity of oxide-free weld joints made of thermo-hardened carbon steel in different electrolytes was investigated by chronopotentiometry, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The objective was to identify the role of different electrolyte constituents on the electrochemical behaviour of the different materials constituting the weld joint, namely the weld material, the heat affected zone (HAZ) and the base carbon steel. Hardness measurements by Vickers and nano-indentation techniques indicated that the weld material is harder than the heat affected zone and the base carbon steel due to a Widmanstatten ferrite-type structure of the weld. Electrochemical measurements were performed on polished cross-sections on these weld joints in four electrolytes containing different additives. The weld joints are active in all tested electrolytes and the composition of the electrolytes dictates the dissolution even though the main chemical reactivity mechanism remains unaffected. A balanced presence of oxidative agent, inhibitor and HF in the electrolyte is necessary to obtain a homogeneous chemical attack on weld joint and Si-rich inclusion removal in weld material, while avoiding excessive attack roughening and/or pitting of the carbon steel.