Indigenous traditional knowledge (ITK) from forest dwellers of Gondia district, Maharashtra

Indians have great knowledge of phytomedicines. This valuable knowledge has been conserved in the living folk traditions in ethnic communities.  An attempt has been made to explore traditional medicinal knowledge of plant materials, available in forest villages of Goregaon and Deori forest range of Gondia district, Maharashtra state. Gondia is one of the prominently categorized districts with maximum tribal population in Maharashtra which includes mostly Gond, Gowari, Halbi, Manah tribes with great numbers. In this study we documented about 49 plant species of various families which are commonly used by the tribal people to cure some common diseases viz. Dysentery, acute headache, toothache and carries, urinary troubles, skin diseases, antidote against snake bite, vomiting and many more. Ethnobotanical information were gathered through several visits, group discussions and cross checked with traditional medical practitioner of the study area

Shear fracture mechanism in micro-tension of an ultrafine-grained pure copper using synchrotron radiation X-ray tomography

In order to investigate the early fracture of ultrafine-grained (UFG) pure copper with a partially recrystallized microstructure and simple shear texture, the evolution of surface strain was measured using in situ micro-tension with digital image correlation. The spatial distribution of voids in tensile specimens was revealed after testing using synchrotron radiation X-ray tomography. The results show that the shear fracture behavior is associated with void evolution in UFG copper and this is strongly affected by the simple shear texture produced by equal-channel angular pressing (ECAP). The results have important implications for use in micro-forming

Oxidation and oxygen diffusion in Ti-6al-4V alloy: improving measurements during sims analysis by rotating the sample

Titanium alloys are attractive to the industrial world, as they offer the benefits of low density, great corrosion resistance, and relatively good strength, making them viable candidates for a multitude of applications. However, above 500 °C, oxidation and oxygen diffusion in titanium alloys need to be taken into account as they change their microstructure and then their mechanical properties. Oxidations were carried out between 600 and 750 °C on a specific titanium alloy: an a-b annealed Ti-6Al-4V. Oxidation kinetics and oxygen diffusion in the matrix were studied. SIMS analyses were realized on rotating specimens of this two-phase polycrystalline alloy in order to reduce roughness. Composition profiles along the sample thickness were compared to microhardness measurements. SIMS mappings were realized on the smooth slopes of the crater

DEFORMATION MECHANISMS IN MULTILAYER MATERIALS AT SMALL LENGTH SCALES

It is now well understood that mechanical behavior of materials at small length scales show some atypical characteristics. As a consequence, these materials show remarkable mechanical and chemical properties. These characteristics can be specified by transitions occurring in strength governing laws such as in the Hall-Petch (HP) relation, confined layer slip (CLS) and interface crossing mechanism in layered materials, and diffusion mediated flow accommodated by grain boundary sliding (GBS) mechanism. In this work, transitions in these mechanisms are further examined when the length scales are decreased from micrometer (µm) to nanometer (nm) regime. This is accomplished by fabricating multilayer materials consisting of alternating layers of different materials. Accumulative roll-bonding (ARB) and physical vapor deposition (PVD) processes are carried out to fabricate the materials at µm and nm length scales, respectively. At µm level, as the length scale is decreased, HP effect shows a transition from opaque interfaces to transparent interfaces to dislocation transmission depicting a decrease in interface energy. This transition is concurrent with the occurrence of bifurcation of deformation accommodation mechanisms in the two layers at ~ 40 µm. As the length scale is decreased further to nm level, the HP effect breaks down and the strength is governed by CLS mechanism down to ~ 7 nm, which is followed by interface crossing mechanism leading to softening at even smaller length scales. These effects were studied in multilayers of dissimilar thicknesses, where the dislocation dominant mechanisms occur in thin layers simultaneously with diffusion dominant processes in thick layers. Therefore, a bifurcation phenomenon is again observed leads to obtaining a configuration where maximum strain hardening rate is obtained due to CLS mechanism and high strain rate sensitivity is obtained due to diffusional flow. This enables us to design materials to show superior mechanical properties such as high strength and high ductility by altering the fabrication routine in multilayered materials. Characterization techniques such as high resolution electron microscopy, electron backscatter diffraction, transmission Kikuchi diffraction, atomic-force microscopy, X-ray diffraction and nanoindentation are implemented

Oxide-scale and Α-casing Characterization in Ti₆Al₄V Alloy Oxidised in Oxygen Gas

Characterization of oxide scale and α-casing in Ti6Al4V titanium alloy oxidized at 1050, 1150, 1250 and 1340 K for 2, 4, 6, 8 and 12 h in a dynamic oxygen gas atmosphere has been analyzed. the oxide scale exhibited a spalling tendency. Its thickness systematically increased with the temperature and the duration of the oxidation. at a later stage the scale exhibited a catastrophic growth due to the increased porosity. the oxygen stabilized α-phase and its volume fraction as well as its hardness decreased with the distance in the metal matrix (α-casing). Estimated oxygen diffusion coefficients based on the hardness profiles across α-casing were 7.0 x 10-14, 8.5 x 10-14, and 1.2 x 10-13, 1.8 x 10-13 m2/s at 1050, 1150, 1250, and 1340 K, respectively. Similarly, the overall activation energy for diffusion of oxygen in the alloy was 105 kJ mol-1. EDS analysis across α-casing in the internal oxidation zone revealed sharp concentration wells for Ti and Al. Titanium concentration decreased and that of aluminum increased in these wells