Lochan Sharma

Bio: Lochan Sharma is an academic researcher from Chandigarh University. The author has contributed to research in topics: Materials science & Welding. The author has an hindex of 7, co-authored 25 publications receiving 125 citations. Previous affiliations of Lochan Sharma include Indian Institute of Technology, Jodhpur.

Fabrication and machining of ceramic composites — A review on current scenario

Abstract: Ceramic matrix composites (CMCs) are the best-suited material for various engineering application due to their superior properties. The different processing methods involved in the fabrication and machining of these CMCs are a center for attraction to researchers and industrial society. This review article primarily focuses on the development of different processing methods and machining methods for ceramic matrix composites since the last few years. Out of these fabrication methods, powder metallurgy emerged as a most promising and cost-effective technique. In addition, electric discharge machining (EDM) has proved to be time saving, cost effective, and capable of machining complex shapes in composites. At the end, challenges in the processing and machining of ceramic matrix composites have been identified from the literature, and further benefits of microwave sintering and electric discharge machining of materials have been addressed in the paper.

Design and development of submerged arc welding fluxes using TiO2-SiO2-CaO and SiO2-CaO-Al2O3 flux system:

Abstract: Submerged arc welding is widely used in pipeline manufacturing due to higher efficiency as compared to the other welding processes In present study, TiO2-SiO2-CaO and SiO2-CaO-Al2O3–based submerge

Design of TiO2–SiO2–MgO and SiO2–MgO–Al2O3-Based Submerged Arc Fluxes for Multipass Bead on Plate Pipeline Steel Welds

Abstract: High strength low alloy steels are extensively used in different applications like oil and gas transmission line pipes, pressure vessels and offshore oil drilling platforms. Submerged arc welding (SAW) is mainly used to weld high thickness steel plates. Flux composition and welding parameters play an important role in determining the adequate quality and mechanical properties of the weld. Agglomerated fluxes were formulated based on TiO2–SiO2–MgO and SiO2–MgO–Al2O3 flux system using constrained mixture design and extreme vertices design approach. The chemical compositions of the bead on a plate have been studied using formulated fluxes. Twenty-one beads on plates were applied using submerged arc welding process keeping the parameters: current, voltage, and welding speed constant. Regression models were developed for bead on plate content in terms of individual, binary, and ternary mixture flux constituents for submerged arc multipass bead on plate deposition for pipeline steel (API 5 L X70). In the present study, chemical composition, grain size, and microhardness properties of the multipass bead on a plate (for API 5 L X70 grade pipeline) were optimized using multi-objective optimization approach.

The new challenges of machining Ceramic Matrix Composites (CMCs): Review of surface integrity

Abstract: Ceramic Matrix Composites (CMCs) are currently an increasing material choice for several high value and safety-critical components, fact that has recently originated the need of understanding the effect of several machining processes. Due to the complex nature of CMCs - i.e. heterogeneous structure, anisotropic thermal and mechanical behaviour and generally the hard nature of at least one of the constituents (e.g. fibre or matrix) - machining become extremely challenging as the process can yield high mechanical and thermal loads. Furthermore, the orthotropic, brittle and heterogeneous nature of CMCs result in different material removal mechanisms which lead to unique surface defects. Hence, this review paper attempts to provide an informative literature survey of the research done in the field of conventional and non-conventional machining of CMCs with a main focus on critically evaluate how different machining techniques affect the machined surfaces. This is achieved by exploring and recollecting the different material characterisation techniques currently used to observe and quantify the mechanical and thermal surface and subsurface damages and highlight their governing removal mechanisms.

Microwave processing of ceramics

Abstract: Summary form only given. We have investigated sintering, both with and without a plasma, reaction bonding of silicon nitride (RBSN), and chemical vapor infiltration (CVI) synthesis of ceramic matrix composites using microwave heating. The sintering rate of alumina in a plasma excited either by microwaves or induction coupling (5 MHz) is significantly greater than with conventional heating. The enhancement is believed to be caused by the creation of excess point defects by the plasma. Both microwave CVI and RBSN seek to take advantage of the temperature gradients inherent in volumetric heating so the reaction or deposition of matrix can take place from the center to the surface, thus enabling a greater degree of reaction than can be obtained by isothermal processing. Experimental and modeling results of these two processes are presented.

Particulate metal matrix composites and their fabrication via friction stir processing – a review

Abstract: Particulate-reinforced metal matrix composites are of particular interest because of their ease of fabrication, low cost, and isotropic properties. Friction stir processing offers a promising alter...