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In the present paper, impedance measurements of the battery configuration, Anode│lithium borophosphate glass electrolyte│LiCoO2 cathode, has been carried out to throw some light on the electrochemical interfacial behavior between the chosen electrodes and electrolyte. The cathode material, lithium cobalt oxide (LiCoO2) has been prepared by three different techniques and characterized. Sol-gel synthesized LiCoO2 showed uniformly distributed spherical shape particles with an average size of 500 nm and also exhibited better electrochemical performance. Charging and discharging (2–3 cycles) of the battery indicated an OCV of 2 V. However, the theoretical OCV of 4 V could not be achieved. The poor performance of the battery could be attributed to the electrochemical processes and SEI film formation at the electrode/electrolyte interfaces. Impedance spectroscopy shows that the major contributions to the impedance of the battery are the electrolyte resistance and the electrode/electrolyte interfacial resistance. With each recharging cycle, the value of electrolyte resistance remains almost constant; however, the interface resistance increases, during the passage of current, due to the interfacial passive layer formation. [ABSTRACT FROM AUTHOR]

Constrained groove pressing is one of the severe plastic deformation techniques to produce ultra-fine grained material. The process defects such as unevenness and cracks on sheet surface limit its commercial applications by reducing the pass numbers thereby the degree of grain refinement. The objective of the present study is to optimize the die design to increase the pass numbers on the basis of die geometry, material properties and sheet thickness by avoiding the local failure. Two response variables namely, maximum equivalent strain and strain inhomogeneity factor, were used to define the objective function. The principal component analysis followed by the gray relational analysis was deployed to develop a single objective function in terms of gray relational grade. A hybrid approach of genetic algorithm followed by gradient-based optimization was adopted to identify the optimal parameters. AA5083 sheets could be successfully deformed with the improved die design while in case of low carbon steel, the number of passes increased from five to seven. The maximum equivalent strain imparted in each material also increased. It has been observed that the yield strength of AA5083 sheet improved by 85% after the first pass with the modified die. [ABSTRACT FROM AUTHOR]

In this experimental work, a mixture of Hydroxyapatite (HAp)+yttrium stabilized zirconia (YSZ) is deposited on a layer of Ti6Al7Nb alloy by electron-beam deposition method, which finds its application in bone and dental implants. Multi-criteria decision making method is adopted (TOPSIS) highlights the close to an ideal solution at the temperature of 160°C (Chamber), 950°C (Furnace), 30 mA (Energy), 90 min (Duration) for achieving the coated layer with optimal thickness. XRD revealed the heat treatment of the samples varying at 450°C and below, tend to shift the sample toward amorphous region due to the inherent nature of electron-beam deposition. To compensate for this, a post-heat treatment has been carried out. From SEM analysis, it is ascertained that coated specimen indicates minimal micro voids and pores, as seen in the cross-sectional area of the HAp/YSZ coated Ti6Al7Nb. The percentage increase from the stoichiometric YSZ and HAp (1.68) to 18.96% (1.99) and 19.20% (1.54) indicates the rise in elemental composition with rise in temperature, attributed to the dissolving nature of P, along with the boundaries of Zr and Ca. In the presence of HAp-YSZ, nano-coated specimen on the substrate would lead to a higher penetration depth along with increase in the strength of the bond formed (adhesive) in the specimen. In the presence of HAp/YSZ powder the corrosion rate falls by 49.34%, attributed to the presence of Zr in YSZ sample creating an addendum for osseointegration. [ABSTRACT FROM AUTHOR]

Polymers are the long chain organic materials that are held together by directional covalent bonds. These kind of organic materials are either synthesized or naturally obtained and they have wide range of application in the medical field due to its physical properties, chemical properties and multifarious processing technique. For the past two decade, these polymers were used to produce variety of medical devices and implants by laser sintering. Since laser based additive manufacturing technique was a thermal process, there may be a change in the material property after sintering and which may affect the usage of the polymer in medical field. This work presented here aims to investigate the material property of biocompatible eos PA12 polymer powder and a laser sintered part. The Scanning Electron Microscope (SEM) with Energy Dispersive Spectroscopy (EDAX), Fourier Transform Infrared Spectroscopy (FT-IR), X-Ray Diffraction (XRD) and Differential Scanning Calorimeter (DSC) analysis were carried out to investigate the properties. The experimental investigation carried out in order to get insight into laser-material interaction and the corresponding results indicated that the laser energy influences the material properties of polyamide powder. [ABSTRACT FROM AUTHOR]

In the present work, double foil butt resistance seam welding in an automotive floor component has been investigated. The possibility of reducing foil from the existing configuration is evaluated. Mechanical properties of the single and double foil weld configuration are compared using tensile tests. The fractography of failed location is analyzed, and the force distribution in base metal and welded specimen is derived analytically to explain the observations in tensile tests. The microstructure and hardness profile of both the weld configurations and their influence on the mechanical properties are analyzed. The weld defect is analyzed using ultrasonic inspection technique. Based on the evaluation of metallurgical characterization and mechanical properties evaluation, the number of foils in an automotive floor component has been optimized. Cost savings of around 30% in the welding process is achieved by foil optimization. [ABSTRACT FROM AUTHOR]

A normal lithium ion conductor, lithium metaphosphate has been taken up for transport studies, as it has enabled for investigation of the Li+ ion transport in (i) crystalline form as LiPO3, (ii) crystalline LiPO3 heterogeneously doped with inert oxide inclusion and homogeneously doped with aliovalent cations, (iii) glassy form as mol% 50Li2O:50P2O5, synthesized by melt-quenching process and (iv) newly identified polymer-metal salt complex (PEO)6:LiPO3. All the above materials have been characterized through XRD, DSC, SEM, Raman spectroscopy and impedance spectroscopy techniques. [ABSTRACT FROM AUTHOR]

In this study, Hill 48 and Barlat 89 yield criteria are evaluated by simulating the Limiting Dome Height test of the Numisheet 96 benchmark problem [1] for a commercial D-grade steel and the results are validated with experimental data. Three strain modes, viz. biaxial, plane strain, and uniaxial strain modes, are used in the simulation studies. The yield criteria are evaluated based on the strain distribution in forming and residual stress distribution after springback. The results show that the Hill 48 and Barlat 89 yield criteria do not show a good match with predicted results of strain distribution in the plane strain mode. The difference between predicted results and experiments can be attributed to the combined influence of friction coefficient and draw bead boundary condition. The prediction of residual stress distribution differed considerably with the yield criteria. The residual stress predicted is validated for selected locations using X-ray diffraction techniques. [ABSTRACT FROM AUTHOR]

High-strength nickel free austenitic stainless steel material as a light-weight substitute for commercial automotive deep drawn steel has been studied with an automotive bumper as an example. The stainless steel gave a weight saving as high as 50% at the same cost that of deep drawn steels. The study examines the techno-economic merits of value engineering automotive material. The bumper made from stainless steel stamping was reduced in thickness to 1.2 mm from 2.5 mm of conventional Extra Deep Draw (EDD) grade steel. Forming behavior of the stainless steel bumper was theoretically simulated and was found to match with experimental observation. The Forming Limit Diagram (FLD) behavior of the stainless steel material shows superior formability. Typical static and impact load cases based on functional requirements of the bumper was simulated, and the light weight stainless steel bumper was found to perform better than the existing EDD bumper. The bumpers made qualified the vibration test requirement. [ABSTRACT FROM AUTHOR]

The structure and low frequency dielectric properties of Pb1-xBax(Yb½Ta½)O3 solid solutions with x = 0.00, 0.10, 0.15, 0.20 and 0.30 have been investigated using X-ray diffraction and dielectric constant measurements. As Ba2+ concentration increases beyond x = 0.15, the crystal structure changes from monoclinic to pseudocubic at room temperature. The sharp paraelectric-antiferroelectric phase occurring in pure Pb(Yb½Ta½)O3, remarkably decreases and simultaneously the weak ferroelectric phase gets enhanced with increase in x. The maximum value of the dielectric constant (Kmax) varies with x, showing a peak value at x = 0.20 whereas dielectric maximum temperature (Tmax) continuously decreases with increase in x. The diffuseness exponent and degree of diffuseness are calculated for x = 0.15, 0.20 and 0.30 by fitting the dielectric data to the modified Curie-Weiss law and the values indicate that the compounds exhibit diffuse phase transition. The paper also discusses the influence of calcination and sintering temperature on the dielectric properties of pure Pb(Yb½Ta½)O3. [ABSTRACT FROM AUTHOR]