International Journal of Microstructure and Materials Properties (11 papers in press)
Wear and hardness evaluation of electrodeposited Ni-SiC nanocomposite coated copper
by Dipak Kumar
Abstract: In this article, NiSiC nano-composite coatings were fabricated using the conventional electrodeposition process, Watt's Nickel electroplating and sulfamate bath, applying on copper substrates. The goal of the present work was to improve wear resistance & hardness properties of Ni-SiC composite coatings by electrodeposition techniques. To obtain a better chemistry between SiC incorporations and Ni matrix and, afterwards, better wear resistance, the variation in the microhardness was considered as significant surface property of nanocomposites by examining the effect of various electrodeposition parameters such as, pH, temperature, current density, temperature, etc. The microhardness,778HV, and the wear resistance of the nanocomposite coatings was found to be increased with increasing content of Ni-SiC at optimized current values of 0.61A. Uniform distribution of coatings structure as cauliflower was confirmed by atomic force microscopy and scanning electron microscopy, while composition & crystallinity of Ni-SiC was confirmed by energy dispersive X-ray spectroscopy & X-ray diffractometry, respectively.
Keywords: Wear and Hardness1; Nickel-SiC Nanocomposite Coating2; Electrodeposition3; Characterization4.
Study of structural and electric properties in polycrystalline Pb(Cd1/3 Ti1/3W1/3)O3 tungsten perovskite
by SANTOSH PARIDA, R. N. P. Choudhary, P.G.R. Achary
Abstract: The presence of tetragonal distortion and the highest degree of spontaneous polarization in lead titanate attracts the researchers compared to another titanate perovskite. For reducing hazardous property, one has to reduce the presence of Pb contents by substituting suitable dopants for different technological applications. A modified lead titanate Pb(Cd1/3W1/3Ti1/3)O3 perovskite is synthesized by a conventional high-temperature solid-state reaction technique. XRD pattern of the sample confirms the cubic crystal structure having space group F-43m. Full proof Rietveld analysis has been used for structural refinement. The presence of FTIR frequency bands corresponding to Ti-O, O-, W-O-W, and CdO stretching confirm that Cd2+, W6+ ions completely substitute the Ti+4 ions at the B site of the perovskite, as confirmed by the XRD obtained data. As the frequency increases from 1 kHz to 5 MHz, the activation energy (Ea) decreases from 0.767 eV to 0.089 eV. The activation energy and conductivity mechanism in the samples dominated by hopping charge carriers. Both Nyquist and Cole-Cole plots confirm the semiconducting nature of the samples and make the material technologically important.
Keywords: Lead Titanate; Perovskite; Activation Energy; Conductivity Mechanism; Hopping Charge; Nyquist plot.
Physical- Mechanical Properties of steel fiber-reinforced self-compacting concrete containing natural perlite addition
by Sabria Malika Mansour
Abstract: The aim of this work is to highlight the effect of the Algerian natural perlite used as fillers addition on the workability and physical- mechanical properties of metallic fiber self-compacting concrete. Effect of the perlite is compared to that of silica fume fillers to replace limestone fillers. One control concrete without fibers containing limestone fillers, two concretes with silica fume or perlite fillers and six self-compacting concretes were elaborated with limestone, perlite and silica fume fillers separately containing 1% vol. of steel long wavy or short hooked fibers. Several tests were conducted for evaluating the workability properties in the fresh state, the density, mechanical strengths and elastic modulus in the hardened state. The results show the beneficial effect of the use of perlite as fillers. Workability properties decrease slightly but an increase of mechanical strengths and elastic modulus is much more marked with the use of the steel hooked fibers.
Keywords: Fillers; Addition; Limestone; Perlite; Silica fume; Self-Compacting Concrete; Workability; Fiber Reinforced concrete; Steel fiber; Compressive strength; Flexural strength; Elastic modulus.
Structural, thermal and electrical properties of polypyrrole filled with ternary oxide Cerium aluminate
by Rani Sutar, Murugendrappa M.V.
Abstract: The effect of dispersion of fillers in different weight percentages on structural, electrical, and humidity sensing properties of polymer matrix has been investigated. Cerium-aluminate (ACO), a double-trioxide compound was used as the filler material in the polypyrrole (PPy) to get PPy/ACO nanocomposites, and the dispersion of the filler was done by an in-situ chemical-polymerization method. The nanocomposites were characterized by various techniques such as XRD, SEM with EDAX, FTIR, and TG/DTA. The room temperature electrical characterizations were carried out by using an impedance analyzer which showed that the lower (10 wt. % and 20 wt. %) and higher (30 wt.%, 40 wt.% and 50 wt.%) filler contents in nanocomposites makes them behave like dielectrics and conductors respectively. The ac-conductivity of the PPy was decreased for 10 and 20 wt.% nanocomposites and then increased for the higher wt. %. The humidity response for the pure PPy and PPy/ACO nanocomposites was studied by using an impedance-analyzer, which shows the improvement in sensing properties.
Keywords: Humidity response; dielectric properties; polypyrrole; cerium aluminate.
Influence of Carbon doping on the Thermoluminescence Properties of LaAlO3 Crystal grown by Solid State Reaction Method
by Kadari Ahmed
Abstract: In this article, we report a modeling investigation of the thermoluminescence mechanisms for the important dosimetric LaAlO3:C crystals, which were grown by solid state reaction method. The aim of this work is to develop for the first time an algorithm that permits the numerical solution of the relevant sets of differential equations governing the different stages of the experimental procedure. The glow curve measured at 10K/s typically consists of three prominent peaks at 417K, 494K and 549K and a minor glow peak at around 372K. In this work, we show that this TL output behaviour can rather easily be explained within the framework of the 4T1R model. Good agreement between the experimental data and calculations from the model is obtained for this kind of dosimetric material. Results presented here confirm that the LaAlO3:C system an excellent candidate that can be used as a TL dosimeter in UV fields.
Keywords: Lanthanum aluminate; Carbon doping; Kinetic parameters; Thermoluminescence model; Ultraviolet dosimeter.
Influence of interlayer temperature on microstructure of 5183 aluminium alloy made by wire arc additive manufacturing (WAAM)
by Karan Derekar, David Griffiths, Sameehan Joshi, Jonathan Lawrence, Xiang Zhang, Adrian Addison, Geoff Melton, Lei Xu
Abstract: The variations in mechanical properties compared to the traditional processed (wrought) products, porosity formation, and solidification cracking are the primary concerns that may restrict industrial applications of WAAM aluminium alloy products. Interlayer temperature is one of the crucial factors that can adversely affect the built quality and properties of material produced using WAAM. The paper aims at the possible effects of different interlayer temperatures on the geometry and microstructure of WAAM aluminium 5183 alloy as a function of varying heat input. For a given heat input, samples built using a higher interlayer temperature (100
Keywords: Wire arc additive manufacturing (WAAM); aluminium; interlayer temperature; microstructure; layer geometry.
Mechanics study of automotive aluminium alloy materials based on elastohydrodynamic model
by Jianna Huang, Xuan Wang
Abstract: To solve the problem of large error in traditional testing methods for automotive aluminium alloy materials, a testing method for mechanical properties of automotive aluminium alloy materials based on elastohydrodynamic model was proposed. Firstly, the elastohydrodynamic model of automobile aluminium alloy material is constructed to obtain the bearing capacity and strength of automobile aluminium alloy material. Secondly, based on the elastohydrodynamic model of automobile aluminium alloy material, the load and yield strength of automobile aluminium alloy material mechanical components are analysed, and the vehicle use is estimated. Parameters of mechanical components of aluminium alloy materials. Finally, the mechanical properties of automotive aluminium alloys were further optimised by the evaluation method of under-actuated two-degree-of-freedom mechanism and the calculation of the coupling eigenfunction of mechanical properties of aluminium alloys and the energy equation of the relationship between friction force and friction coefficient.
Keywords: elastohydrodynamic model; aluminium alloy materials; mechanical properties; thermoelasticity; testing method; mechanical components.
Translucent α- and α/β-SiAlON ceramics: study on investigation of the relationship between phase diversity and optical properties
by Suna Avcıoğlu, Semra Kurama
Abstract: In this study, Dy+3, Y+3, and La+3 doped SiAlON ceramics were fabricated by using spark plasma sintering (SPS) technique. The effects of additive cation, starting composition and processing conditions on the morphological evolution as well as on the phase assembly of SiAlON ceramics were investigated. The influence of phase diversity on the optical properties of SiAlON ceramics was also discussed. Results indicate that the translucent α- SiAlON, α/β-SiAlON ceramics and their in-situ composites with AlNpolytypoids could be successfully obtained. The presence of a high amount of secondary phases such as AlN-polytype and the oxynitride glassy phase has been found to reduce the optical transmission of SiAlON ceramics. The doping of Y+3 and Dy+3 cations contributed better to the formation of single-phase α-SiAlON than that of La+3. Doping SiAlON ceramics with Dy+3 cation leads to the formation of relatively homogeni ed final microstructure. Therefore, higher IR transmission values were observed on Dy-α-SiAlON (42.2%) and Dy-α/β-SiAlON (45.07%) samples.
Keywords: SiAlON; transparent polycrystalline ceramics; dopant; phase composition; SPS; spark plasma sintering; microstructure; optical properties; AlN-polytypoids.
Effect of different sintering conditions on microstructural characterisation of Co-Cr metal laser powder
by Gürel Pekkan, Eda Taşçı, Keriman Pekkan, Murat Ispalarlı
Abstract: Co-Cr alloys have been used for many years in dentistry. In recent years, the fabrication of prosthetic restorations from Co-Cr alloys by metal laser sintering method has become widespread. This method is a combination of powder metallurgy and three-dimensional printing technologies. The surface microstructure of the material and the different phases formed on the surface of the material after sintering and heat treatment are extremely important since these metal substructures are layered with dental porcelain in fixed prosthetic dentistry. In this study, characterisation of Co-Cr alloy samples produced by direct metal laser sintering (DMLS) method and sintering under various atmospheric conditions were performed with X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy-dispersive X-ray diffractometer (EDX). It was observed that sintering with different methods under various atmospheric conditions affected the XRD phase intensities. The sintering in the argon gas atmosphere yielded a more significant phase separation that facilitates the identification of different phases in XRD patterns.
Keywords: laser metal powder; selective laser sintering; characterisation; XRD; X-ray diffractometer; SEM; scanning electron microscope; EDX; energy-dispersive X-ray diffractometer; Co-Cr alloy; argon.
Effect of short carbon fibres on the fresh state and compressive strength properties of self-compacting concrete
by Iftekar Gull, M.A. Tantray
Abstract: This study highlights the fresh state flow properties and hardened state compressive strength properties of short carbon fibre reinforced selfcompacting concrete. 15 mixes with varying W/C ratio, cement content, and the percentage of carbon fibres were investigated. The impact of the variations on the self-compacting concrete was analysed by comparing the mixes to the control mix. The present study investigations revealed a decrease in filling and passing ability of CFRSCC with the addition of higher percentages of carbon fibres while the addition of carbon fibre at lower percentage exhibits improvement in the filling, passing and segregation resistance properties. It was also observed that with the inclusion of short carbon fibres, the compressive strength was significantly improved. The microstructure of the CFRSCC with different percentages of Carbon fibre was also analysed and is presented in this study.
Keywords: pitch-based short carbon fibres; self-compacting concrete; filling ability; passing ability; segregation resistance; compressive strength; scanning electron microscopy; regression analysis; carbon fibre failure mechanism.
Long-term performance of concrete using additives
by Kiran Devi, Babita Saini, Paratibha Aggarwal
Abstract: The increase in global warming due to emission of greenhouse gases especially during the production of cement has become threat to the environment. The development of sustainable and economical materials has become need of the present scenario. Also, direct disposal of waste from stone industries is becoming serious issue to ecosystem and need its safe disposal. Accelerators are being used to accelerate stiffening and early age strength development of mortar/concrete. In this study, Kota stone powder (KSP) as partial substitution to cement and admixtures, i.e., calcium nitrate, triethanolamine as additives were used individually and in combination to examine their influence on strength, durability and micro-structural properties at later age. The aim of study was to check the viability of these materials in concrete under different environmental conditions; and to make sustainable concrete by reducing cement and cost. Admixtures and stone powder individually improved the properties; while, their mixture diminished concrete properties.
Keywords: calcium nitrate; triethanolamine; Kota stone powder; mechanical strength; electrical resistivity; chemical resistance; correlation; micro-structural analysis; economic analysis.