Articles written in Bulletin of Materials Science
Volume 14 Issue 3 June 1991 pp 819-825 International Conference On Superconductivity—II
We report thermoelectric power measurements on BiSrCaCuO (2212) superconducting oxide and compare the observed behaviour with that of the YBaCuO (123) system. The relative importance of phonon drag and diffusion thermopower contributions is evaluated for the two systems by analysing the data using a generalized expression of the type
Volume 23 Issue 2 April 2000 pp 97-101 Magnetic Materials
The magnetic behaviour of two ferromagnetic oxides and two ferrimagnetic oxides (ferrites) are compared to study the effect of magnetocrystalline anisotropy on thermal-history-dependence of magnetization of these ordered magnetic systems. All four compounds show thermomagnetic irreversibility (
Volume 29 Issue 2 April 2006 pp 147-154 Alloys
Tensile behaviour of the near 𝛼 titanium alloy, Ti–6Al–5Zr–0.5Mo–0.25Si (LT26A), was investigated in (𝛼+𝛽) as well as 𝛽 treated condition, over a wide range of temperature from RT to 823 K. It was observed that there were distinct serrations on the load-elongation curves of the 𝛼 + 𝛽 treated material at intermediate temperatures from 623 to 723 K. Tensile tests at 673 K over a wide range of strain rate from 0.052 to 5.60 (× 10-2) s-1 showed negative strain rate sensitivity. Thus, occurrence of DSA was confirmed. It was established from the measured activation energy for DSA that it was essentially controlled by diffusion of the solid solution strengthener silicon in the matrix.
Volume 29 Issue 3 June 2006 pp 271-275 Alloys and Steels
Low cycle fatigue (LCF) behaviour of the near 𝛼 titanium alloy, Ti–6Al–5Zr–0.5Mo–0.25Si (LT26A), was investigated in the (𝛼 + 𝛽) as well as 𝛽 treated conditions at room temperature. LCF tests were carried out under total strain controlled mode in the range of 𝛥 𝜀t/2: from ± 0.60% to ± 1.40%. The alloy shows cyclic softening in both the conditions. Also it exhibits dual slope Coffin–Manson (C–M) relationship in both the treated conditions.
Volume 37 Issue 3 May 2014 pp 597-602
Advanced materials such as continuous fibre-reinforced polymer matrix composites offer significant enhancements in variety of properties, as compared to their bulk, monolithic counterparts. These properties include primarily the tensile stress, flexural stress and fracture parameters. However, till date, there are hardly any scientific studies reported on carbon fibre (Cf) and carbon nanotube (CNT) reinforced hybrid epoxy matrix composites (unidirectional). The present work is an attempt to bring out the flexural strength properties along with a detailed investigation in the synthesis of reinforced hybrid composite. In this present study, the importance of alignment of fibre is comprehensively evaluated and reported. The results obtained are discussed in terms of material characteristics, microstructure and mode of failure under flexural (3-point bend) loading. The study reveals the material exhibiting exceptionally high strength values and declaring itself as a material with high strength to weight ratio when compared to other competing polymer matrix composites (PMCs); as a novel structural material for aeronautical and aerospace applications.
Volume 38 Issue 7 December 2015 pp 1723-1729
The growth of graphene by chemical vapour deposition (CVD) on copper is the most promising scalable method for high-quality graphene. The use of ethanol, an economic and safe precursor, for the fast growth of graphene on copper by a home-built CVD set-up was analysed. Full coverage of uniform single-layer graphene with high crystalline quality was found on $\langle100\rangle$ textured Cu foils in just 30 s. The nucleation density of graphene islands was found to be independent of facets but the island shape showed facet dependence. Diamond-like islands were observed on Cu(100) facets while random shaped islands were seen on other facets. The last observation is discussed in terms of a competition between graphene-island growth and its relaxation rate on different facets. On Cu(100) slower island growth as compared to its relaxation leads to equilibrium shapes as opposed to other facets. Further, an observed evolution in graphene contrast in electron micrographs with time on different facets was discussed in terms of oxygen diffusion between graphene and Cu.
Volume 43 All articles Published: 29 July 2020 Article ID 0171
Fused filament fabrication (FFF) is an extrusion-based 3D printing technique for thermoplastic polymers. In this technique, molten polymer is extruded through a print nozzle and is laid down layer by layer to build up the printed object.Currently, FFF is used primarily to print amorphous or low-crystallinity polymers, such as acrylonitrile butadiene styrene copolymer (ABS) or polylactic acid (PLA). Printing of semicrystalline polymers, such as polyethylene or polypropyleneremains particularly challenging. During FFF of semicrystalline polymers, large thermomechanical stresses are generated when the polymer solidifies on cooling. These stresses result in warpage of the printed part. Here, we analyse the factors that influence stresses generated during FFF 3D printing of a commercial semicrystalline polymer, isotactic polypropylene. We investigate the effect of height of the printed object on part warpage, as well the effect of infilling during printing. We demonstrate that the stresses generated during FFF can be substantially decreased by incorporation of a ‘brim’, viz. a thin layer at the base of the printed object, and by adhering the brim to the print substrate using common polyvinyl acetate based glue. We systematically investigate the effect of the brim size on the warpage of the printed object. We support ourexperimental findings with finite element method (FEM) simulations that explain the mechanism of stress buildup during printing. The trend in stresses calculated in the FEM simulations parallel the warpage measured in the experiments. Thus,this work represents an important methodological advance towards warpage-free FFF printing of semicrystalline polymers.
Volume 43, 2020
Continuous Article Publishing mode
Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020
Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
Physical Sciences 2020
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