Department of Metallurgical & Materials Engineering

&ldquo;IIT Jodhpur is committed to impart quality education to facilitate the creation of qualified, competent and responsible human resources to meet the emerging technological challenges of the world. It is working towards creating an equitable learning platform that is positive, accessible and effective in the face of the modern societal and scientific advancements.

Flexibility in curriculum, in all its academic programs, encompassing elements of teaching, research, creativity, innovation and entrepreneurship is the most unique feature of IIT Jodhpur. The Department of Science and Technology (DST), under the National Mission on Cyber Physical Systems, has identified IIT Jodhpur as a Technology &amp; Innovation Hub in the area of Augmented Reality and Virtual Reality. The institute has also been nominated as the coordinator for the Jodhpur City and Knowledge Cluster by the Office of Principal Scientific Adviser, Government of India.

The sprawling 852-acre IIT Jodhpur campus is a majestic tribute to the deep-rooted diverse cultural heritage of the region. The campus is an architectural masterpiece, which is slated to become an international exemplar of sustainability with net-zero energy, and advanced water and waste management strategies.&rdquo;

IIT Jodhpur

Solar energy is the most efficient and economic gateway for power generation. The development of solar research and technological innovation, and corresponding decline in the prices of solar power harnessing devices, has paved the way for low-cost energy generation in developing country, India. It is estimated that if at least 10% of the total geographical area are effectively utilized, the available solar energy would be 8 million MW, which is equivalent to ~6000 Mtoe per year (https://www.indiaenergyportal.org/subthemes.php?text=solar ). However, installed photovoltaic systems including the solar panels in desert areas and in the industrial areas are prone to the accretion of dust and dirt particles. This resultant fouling hinders the conversion of incident light into electricity, causing a decline in the energy conversion efficiency up to 50%. To maintain a steady performance of PV panels, the surfaces of which must be cleaned regularly. However, current methods of cleaning are expensive, inefficient, and potentially harmful to the surfaces. With recent progress in nanotechnology research, nanostructured coatings have become multifunctional, efficient, and smart. Particularly, self-cleaning coatings have gained considerable attraction owing to its application in a wide range of fields. In this chapter, a brief review regarding the recent progress of bio-mimic self-cleaning coatings on photovoltaic solar systems is presented. A brief introduction on the types of self-cleaning coatings and their properties, such as wettability, optical transparency, mechanical durability, and environmental durability characteristics, is discussed. A short note on the considerations and developments regarding the fabrication of durable, self-cleaning coatings for photovoltaic systems has been presented. © 2021, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

World University root node

Energy, Environment, and Sustainability

A Brief Review on Self-cleaning Coatings for Photovoltaic Systems

Surface mining causes significant wear damage that affects equipment performance, reliability, and lead to associated downtime costs. To improve the wear resistance of components used in natural resources industries, cemented carbide tiles are joined to engaging surfaces of the components. Joining of cemented carbide to structural steel can be achieved by various processes, among which brazing is commonly used owing to its relatively simple processing and low cost. A significant challenge in brazing cemented carbide tiles to steels is the poor joint strength. This article aims to review the recent progress in improving joint strength of cemented carbide/steel brazing. Recent progress on the key factors, including type of filler metals, evolution of joint microstructure, generation of residual stresses, and process parameters have been closely examined and critically analysed. Future directions of research on brazing cemented carbide tiles to steel in order to improve joint strength have been proposed. © 2021 Institute of Materials, Minerals and Mining. Published by Taylor & Francis on behalf of the Institute.

Science and Technology of Welding and Joining

Progress in Improving Joint Strength of Brazed Cemented Carbides and Steels

The bondline of electric-resistance-welded (ERW) linepipe steel, often etched white (i.e., ferrite) in optical microscopy, is generally believed to be carbon depleted. The mechanism for the carbon depletion, however, is not fully understood by researchers. To this end, atom probe tomography (APT) was used to measure elemental segregation of the as-welded and post-weld heat-treated bondline regions of X70 linepipe welds. The thin vertical features at the bondline in the as-welded condition were identified as carbon-rich martensite-austenite (M-A) constituents, and the majority ferrite phase in the bondline was identified as carbon-depleted ferrite. Following the post-weld normalization, all alloying elements, except Nb and Mo, are homogenized across the bondline and heat-affected zone. The carbon depletion in the ERW bondline was accurately measured. A new mechanism for carbon depletion has been proposed using Scheil calculations of elemental partitioning during weld formation. Segregation of elements in the heat-affected zone was shown to follow the negligible partitioning local equilibrium (NPLE) kinetics for bainite transformation. © 2021, The Minerals, Metals & Materials Society and ASM International.

Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

A Mechanism for Carbon Depletion at Bondline of High-Frequency Electric-Resistance-Welded X70 Pipeline Steel

A straightening fracture of an AISI 1045 pump rod with a fused coating by thermal spray welding was investigated. The fracture surface was surveyed for pinhole-related defects in the coating, debonding at the coating/substrate interface, and fracture initiation points. The base metal and coating were also examined using an optical microscope, scanning electron microscope with energy dispersive spectroscopy, tensile testing, and microhardness testing. The base metal rod experienced softening due to the thermal effect of spray welding and fusion. Large residual stress has been found in the outer coating layer using finite element analysis. The open-to-surface crack in the base metal was found to be partially filled by the hard coating. The brittle fracture is believed to be initiated at defects near the coating/rod interface and driven by a combined loading of thermal residual stresses and the applied straightening stress. © 2021 Elsevier Ltd

Engineering Failure Analysis

Fracture of Ni-Cr-Si-B thermal sprayed and fused reciprocating pump rods during straightening

Graphene, an atomic thin sheet of monolayer carbon atoms, is deemed to replace silicon and revolutionize the electronics industry. It has massless Dirac fermions and exhibits ballistic charge transport, a prerequisite for upcoming futuristic nanodevices, such as field-effect transistors, sensors, etc. However, it lacks an intrinsic electronic bandgap and thus is obsolete for use in these applications. In this work, a first principles study is used to predict the opening of a bandgap in graphene by an engineered introduction of modulations in its lattice. Moreover, it is found that the atomic modulation and the addition of hydrogen atoms at sub-lattices induce magnetism in the graphene sheets. The hydrogen-induced itinerant magnetism (ferromagnetic or antiferromagnetic) depends on the type of defects and the structure of the sheet. This hydrogen-induced spin promotes the role of graphene as a potential material for magnetic memory device applications. Furthermore, with the creation of atomic vacancies and quasilocalized states, it is deemed to allow selective permeation (water/gas) and thus paves the way for its use in-filtration (membrane technology) and hydrogen storage applications. © 2021 IEEE.

2021 6th International Conference on Renewable Energy: Generation and {\ldots}

Graphene for next generation magnetic devices: A first-principles study

Ovchinnikov postulated the possibility of ferromagnetism in organic compounds having a mixed density of sp 3 and sp 2 carbon atoms. Such systems provide an interesting avenue for exploring magnetism in the absence of the quintessential d- and f-block elements as ingredients. As graphene oxide (GO) and its derivatives naturally possess a mixture of sp 3 and sp 2 carbon atoms, it is pertinent to look at them as potential candidates for Ovchinnikov ferromagnetism. We have looked at the evolution of magnetic property in a series of GO samples with a gradual increase in the degree of oxidation and hence the sp 3/sp 2 fraction. Starting with a GO sample with a high sp 3/sp 2 ratio, we utilize chemical reduction technique to prepare another set of reduced graphene oxide (rGO) samples. Magnetization measurements on these samples further illustrate the importance of sp 3/sp 2 fraction on magnetic behavior suggesting GO and its derivatives as a potential Ovchinnikov ferromagnet candidate. The evolution of magnetic moment with sp 3/sp 2 carbons can be utilized in carbon based spintronic applications.

Journal of Physics Condensed Matter

Graphene oxide and its derivatives as potential Ovchinnikov ferromagnets

Small

Catalyzing Bond‐Dissociation in Graphene via Alkali‐Iodide Molecules

The influence of radiation-induced (1 MeV energy H+ to ∼0.1 displacements per atom (dpa) at 450 °C), nonequilibrium point defect populations on mass transport is studied with an integrated campaign of experimental and theoretical methods. Using epitaxial thin films of hematite (α-Fe2O3) with embedded 18O tracer layers and nanoscale atom probe tomography measurements, it is shown that anion self-diffusion is enhanced by at least 2 orders of magnitude under irradiation compared to thermal diffusion alone. Complementary scanning transmission electron microscopy of vacuum-annealed and irradiated specimens reveals associated microstructural changes near the surface of the oxide films, including local phase transformation to Fe3O4 and the development of nanoscale voids from vacancy coalescence. Point defect formation and migration energies were computed from density functional theory and applied within the context of the chemical rate theory to analyze contributions from both interstitial and vacancy mechanisms to self-diffusion in thermal and irradiation conditions. Comparisons are made between calculated, literature, and newly measured self-diffusion values, revealing good agreement on the magnitude of radiation-enhanced anion diffusion. Further, the model suggests a transition from vacancy to interstitialcy mechanisms at low temperatures and high oxygen activity, providing an explanation for the varied activation energies reported from prior studies. © 2021 American Chemical Society.

Chemistry of Materials

Radiation-Enhanced Anion Transport in Hematite

Despite the fundamental importance of mass transport, there is still a lack of knowledge regarding the mechanisms in many materials. In particular, how the magnetic spin structure interacts with migrating defects is unclear. Here, using density functional theory to examine cation interstitial transport in antiferromagnetic corundum-structured oxides, we reveal an interplay between the migration of the interstitial and the magnetic structure of the oxide. The magnetic spin configuration impacts the migration energy of the migrating defect but, critically, the defect modifies the spin configuration. Thus, the two aspects change in concert to modify one another. This has profound implications for mass transport in magnetic materials. © 2021 American Physical Society.