Articles written in Bulletin of Materials Science

• Anisotropy of mechanical properties in quaternary Al-Li-Cu-Mg alloys

Considerable anisotropy in the mechanical properties of quaternary Al-Li-Cu-Mg alloys was observed in both plate and sheet products. These alloys showed more than 100% increase in tensile ductility in the test direction oriented at 45–60° to the rolling direction as compared to that in the rolling direction (longitudinal, L). A concomitant decrease in strength was also found. These alloys exhibit superior low cycle fatigue resistance in the long-transverse (LT) direction as compared to the longitudinal (L) direction. Another observation is the occurrence of strength differential (S-D), which is seen to be directional. The trends in S-D are similar under monotonic as well as cyclic loading conditions. The fracture resistance is also highly anisotropic. An attempt is made here to correlate the observed anisotropy in the mechanical behaviour of these alloys with the microstructure and crystallographic texture.

• Factorial design, processing, characterization and microstructure analysis of PIP-based C/SiC composites

Polymer impregnation and pyrolysis (PIP) process-based C/SiC composites are fabricated using the in-housesynthesized methyl-polycarbosilane (PCS). Two-level factorial design matrix is employed to carry out experiments to studythe effect of four factors on flexural strength of the composite.Total sixteen sets of composite samples are fabricated.Responsetable, normal probability plot, ANOVA and regression analysis are carried out to determine the statistical significant factors.Composite density ($\rho$), fibre volume fraction ($V_{\rm f}$ ) and pyrolysis temperature ($T$) are found to be statistically significant, while softening point (SP) of the PCS and interaction of these four factors are found insignificant. Higher levels of thedensity and $V_{\rm f}$ have shown positive effect, while the pyrolysis temperature has negative effect on the flexural strength of the composites. Flexural strength was found to be in the range of 374–592 MPa depending on the process parameters. Themechanical behaviour of the composites at different process conditions was explained with the help of their microstructures.

• Analysis of carbon-based nanomaterials using Raman spectroscopy: principles and case studies

The advent of new instrumentation techniques provides the breakthrough for Raman spectroscopy to establish as powerful non-invasive method for material characterization. In recent years, carbon-based materials and particularlynanomaterials emerged as the subject of enormous scientific and technological attention due to their outstanding mechanical, electrical and thermal properties. We present a brief account on the unprecedented opportunity of Ramanspectroscopy for insight into the behaviour of electrons and phonons in carbon nanomaterials. Raman scattering techniques have been highlighted which can be exclusively used to understand the critical dependence of the ratio of sp$^2$(graphite-like) to sp$^3$ (diamond-like) bonds with the physical properties of honeycomb carbon lattice. The different case studies carried out in our laboratory were included to underline the fact that the Raman is the backbone of non-destructive, fast and high-resolution characterization tool to provide the maximum structural features, lattice dynamics and electronic information in carbon materials at various length scales.

• # Bulletin of Materials Science

Volume 44, 2021
All articles
Continuous Article Publishing mode

• # Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020