Kalainathan S

Department of Physics

School of Advanced Sciences

Vellore Campus

Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Materials & Design

The pulsating current approach in <a href="https://www.sciencedirect.com/topics/engineering/tungsten">tungsten</a> <a href="https://www.sciencedirect.com/topics/engineering/inert-gas">inert gas</a> (TIG) welding is adapted for joining <a href="https://www.sciencedirect.com/topics/engineering/hastelloy">Hastelloy</a> C-276. <a href="https://www.sciencedirect.com/topics/engineering/microstructure">Microstructure</a> examination revealed the absence of micro-segregation while employing UNS N06022 filler. Due to the prevalence of <a href="https://www.sciencedirect.com/topics/engineering/high-tensile-stress">higher tensile stresses</a> in the un-peened conditions, tensile failures were observed in the weld regions of both the joints irrespective of fillers. Low <a href="https://www.sciencedirect.com/topics/engineering/energy-engineering">energy</a> <a href="https://www.sciencedirect.com/topics/engineering/laser-shock-peening">laser shock peening</a> without coating (LSPwC) was carried out on the weld zones on both the sides of the joints with the pulse densities 2500 and 7500 pulses per cm2. This <a href="https://www.sciencedirect.com/topics/engineering/laser-surface-treatment">laser surface treatment</a> had remarkably increased the <a href="https://www.sciencedirect.com/topics/engineering/tensile-strength">tensile strength</a> of the welded joints by shifting the location of tensile failures well away from the fusion zones for all the cases. Similarly, a considerable increase is observed in the <a href="https://www.sciencedirect.com/topics/engineering/notch-toughness">notch toughness</a> of both the joints in the LSPwC condition. The enhancement in tensile strength and notch <a href="https://www.sciencedirect.com/topics/engineering/impact-toughness">impact toughness</a> of the welds could be ascribed to the <a href="https://www.sciencedirect.com/topics/engineering/compressive-residual-stress">residual compressive stresses</a> induced which were then confirmed by Sin2ψ method in <a href="https://www.sciencedirect.com/topics/engineering/x-ray-diffraction">X-ray diffraction</a> (XRD) technique.

Journal of Materials Processing Technology

Effect of low energy laser shock peening on the mechanical integrity of Hastelloy C-276 welds

Optics & Laser Technology

Residual stress, phase, microstructure and mechanical property studies of ultrafine bainitic steel through laser shock peening

Surfaces and Interfaces

Laser shock peening modified surface texturing, microstructure and mechanical properties of graphene dispersion strengthened aluminium nanocomposites

This research work investigates the effect of laser shock peening (LSP) on commercially pure titanium grade 1 (CP Ti-1) weldment. The welding was done using gas tungsten arc welding (GTAW) with ERTi-2 filler wire. LSP was carried out on the cap surface of the weldment. The optical microstructure showed the Widmanstatten-type martensitic structure in the fusion zone (as-welded). The LSP fusion zone showed a refined microstructure compared to that of as-welded condition. Scanning electron microscope (SEM) of LSP weldment showed the indentation on the surface of the weld. This was a result of the surface ablation that occurred during LSP. X-ray diffraction analysis showed the absence of transformation of phases in the weldment. A reduction of 14.8% of crystalline size was observed in LSP weldment. A higher compressive residual stress was observed in LSP weldment than the as-welded condition. Tensile test showed the occurrence of failure in the base metal region in the case of LSP weldment, as against the failure in the case of as-welded condition in the fusion zone. © 2019, The Indian Institute of Metals - IIM.

Transactions of the Indian Institute of Metals

Effect of Laser Shock Peening on Commercially Pure Titanium-1 Weldment Fabricated by Gas Tungsten Arc Welding Technique

Microsegregation of alloying elements is prone to hot cracking in the weldment of alloy C-276. The formation of topologically close packed phases P and µ is largely responsible for the hot cracking. The present study articulates the effect of laser shock peening (LSP) to improve the metallurgical and mechanical properties of the weld joint. The weld joint was fabricated by pulsed current gas tungsten arc welding (PCGTAW) using an ERNiCrMo-3 filler wire. LSP without coating was carried out on the cap surface of the weldment. Microstructural studies were carried out to compare the as-welded and laser-peened microstructure on the fusion zone. The results show that a fine equiaxed dendritic structure was observed in both conditions. EDS analysis was carried out to evaluate the microsegregation of alloying elements. EDS analysis indicates that there are no secondary intermetallic phases. X-ray diffraction analysis was carried out to evaluate the phase change and crystallite size in the as-welded and laser shock peened fusion zone. The result shows 48.99% reduction in crystallite size after LSP. Hardness and tensile strength results indicate there is a consequential increase in laser shock peened specimen compared with as-welded specimen. © 2018, Indian Academy of Sciences.

Fulltext

Sādhanā

Surface modification technique to enhance metallurgical and mechanical properties of alloy C-276 weldment by laser shock peening without coating

Recent development and future perspectives of low energy laser shock peening

The present study investigates the effect of laser peening without coating on aluminum alloy Al-6061-T6 with a 300 mJ infrared laser. The surface topography, microstructure, surface topography, surface residual stress and micro-hardness of peened and unpeened surfaces were studied. The study shows that laser peening without coating can significantly improve surface compressive stress and micro-hardness with trivial increase in surface roughness. Microstructure evaluation confirmed there was no near surface solidification after LPwC. © 2012 Elsevier Ltd.

Laser peening without coating on aluminum alloy Al-6061-T6 using low energy Nd:YAG laser

This paper discusses the results of laser peening without coating on low carbon austenitic stainless steel 316L. Unlike typical experiments on laser peening without coating (LPwC) performed with frequency doubled (green) laser and underwater irradiation, the present study reports LPwC with infrared radiation using thin layer of water as confinement medium. The dependence of laser pulse density on properties such as surface roughness, surface residual stress, microhardness, and corrosion behavior of LPwC specimen were investigated. The magnitude of surface compressive residual stress on laser peened specimen showed appreciable improvement compared to unpeened base material. Microhardness of the specimen improved by 3040% after LPwC. However, the potentiodynamic polarization study indicated that though there is an enhancement of corrosion potential (E corr), the corrosion current density (I corr) increased with increase in laser pulse density. © 2012 Elsevier Ltd.

Optics and Lasers in Engineering

Effect of laser shot peening without coating on the surface properties and corrosion behavior of 316L steel

Effect of laser shot peening on precipitation hardened aluminum alloy 6061-T6 using low energy laser

[INVITED] A review: Warm laser shock peening and related laser processing technique

Warm laser shock peening without coating induced phase transformations and pinning effect on fatigue life of low-alloy steel

Journal	Data powered by TypesetMaterials & Design
Publisher	Data powered by TypesetElsevier BV
ISSN	0264-1275
Open Access	0