Sagar Sarkar

Sagar Sarkar
Indian Institute of Technology Delhi | IIT Delhi · Department of Mechanical Engineering

Ph.D
Additive Manufacturing and Laser Material Processing

About

43
Publications
11,910
Reads
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546
Citations
Citations since 2017
35 Research Items
529 Citations
2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
2017201820192020202120222023050100150
Introduction
My research interests include understanding the mechanical properties of additively manufactured parts under dynamic loading conditions mainly fatigue and online process monitoring in laser based additive manufacturing processes to ensure repeatable and reproducible part properties. Also, I am actively involved in other laser material processing applications and open to collaborative research works to develop better understanding of the process.
Additional affiliations
June 2019 - June 2021
Indian Institute of Technology Kharagpur
Position
  • Research Officer
Education
December 2014 - June 2019
Indian Institute of Technology Kharagpur
Field of study
  • Laser Additive Manufacturing
July 2009 - July 2014
Indian Institute of Technology Kharagpur
Field of study
  • Department of Mechanical Engineering

Publications

Publications (43)
Article
In today's era of modern manufacturing, selective laser melting is getting increasingly popular due to its capability of producing geometrically complex parts directly from CAD model in a single step. Few papers have reported the fatigue behaviour of selective laser sintered stainless steel specimens. In the present study, effect of tensile, zero a...
Article
One of the most popular additive manufacturing processes is laser based direct metal laser sintering process which enables us to make complex three dimensional parts directly from CAD models. Due to layer by layer formation, parts built in this process tend to be anisotropic in nature. Suitable heat treatment can reduce this anisotropic behaviour b...
Chapter
Laser surface hardening is a well-established process for enhancing the mechanical properties of selected surface areas of engineering parts made of different types of steel. Since this was first reported in the early seventies, much research has been done since to develop a deeper understanding of the process, process modeling for determining oper...
Article
Laser Assisted Cold Spray (LACS), a hybrid deposition process can be used to deposit crack free coatings in solid state with high compressive residual stress for variety of materials. However, high gas consumption rate, high maintenance cost, and costly experimental set-up often restricts its widespread usage in industries. The present work attempt...
Article
The present article reports the fatigue crack growth (FCG) rate and fracture toughness of 15-5 Precipitation Hardening (PH) Stainless Steel (SS) specimens fabricated by Laser powder bed fusion (L-PBF) additive manufacturing (AM) technique. The effect of notch orientation (parallel and orthogonal in reference to build direction) on FCG and fracture...
Article
The laser coating of NiCrBSi in pure form as well as with the addition of lubricious Ag or WS2 has been developed on Ti6Al4V substrate. With the help of an IR pyrometer, real-time thermal history was monitored and correlated with the tribological properties of the coating. A matrix predominantly comprised of NiTi and NiTi2 and reinforced with hard...
Article
Full-text available
Surface properties play a critical role in the structural integrity of any component and this becomes even more critical for weld joints. Laser shock peening (LSP) is one of the non-contact methods which is getting popular in industries to enhance surface properties for improving service life, mainly fatigue of engineering components. In the presen...
Article
Friction stir welding (FSW) of CuCrZr sheets was performed and Laser Shock Peening (LSP) was carried out as a post-weld surface treatment. Effect of LSP on hardness, tensile and fatigue strength was investigated. Depth of compressive residual stress in base material increased from 550 µm to 700 µm when the number of LSP shots was increased from one...
Article
In-situ laser deposition of Ni powder as an interlayer has been exploited to join dissimilar metals, titanium and stainless steel. Direct fusion joining of these materials often suffers from longitudinal cracks due to the formation of hard and brittle intermetallics of Ti and Fe, and also transverse cracks because of large difference in their therm...
Chapter
Laser powder bed fusion technique has been considered as one of the best metal additive manufacturing processes considering the part quality and dimensional accuracy. However, the high cost of metal powders makes it difficult to afford for all kinds of applications. Reusability of the powders can overcome this issue, but the effect on various mater...
Article
Additive manufacturing (AM) has been widely considered as a popular manufacturing technique for the production of specific engineering components by various industries. Among the various AM techniques, laser powder bed fusion process (L-PBF) has the potential to make defect-free parts with good material properties. However, the mechanical propertie...
Chapter
Laser cladding of Ni-based superalloys has been studied extensively in the recent past owing to their combined properties of high strength and corrosion resistance at elevated temperatures, due to which they are finding wide applications in gas turbine engines, land-based power-generation gas turbines, nuclear and fossil fuel power plants, etc. The...
Article
Full-text available
In the present study laser beam welding of commercially pure titanium is carried out at different welding speeds. Effect of the addition of active flux layer of MgF2 on the morphology and geometry of the weld zone and surrounding regions is investigated along with its influence on the tensile strength of the welded joints. The active flux narrowed...
Article
Deposition of ceramic-metal matrix composite using laser directed energy deposition process presents multi-fold challenges. High melting point ceramic particles often remain partially melted and increase the roughness of the deposit, which essentially requires secondary finishing operation. Besides high surface roughness, the high gradient of therm...
Article
Layer by layer deposition in laser based metal additive manufacturing process causes accumulation of high thermal residual stresses. This may sometimes lead to dimensional inaccuracy and warping of the deposited clad layer. Additive manufacturing being expensive process, simulation may reduce the number of experimental trails. In the present work,...
Article
In the present study, laser beam welding of commercially pure titanium has been carried out at different scan speeds in the range from 2.4 m/min to 4 m/min at 2.15 kW laser power and its influence on molten pool thermal history, microstructure, residual stress, mechanical and corrosion properties has been studied. Weld thermals cycles were monitore...
Article
A novel method of monitoring cooling rates in real-time using two pyrometers arranged in tandem has been demonstrated. First pyrometer monitors the temperature at the center of the molten pool, second monitors the temperature at its tailing end. The difference in two pyrometer signals provides the temperature gradient at 1 kHz frequency from which...
Article
Direct metal laser deposition of ceramic-metal composite coatings has received much attention in the recent past over other conventional methods due to a large number of advantages. However, formation of cracks due to large thermal gradients and rapid cooling rates limits its application. Therefore, in the present study the influence of cooling rat...
Article
With recent advancements in additive manufacturing, Selective Laser Melting (SLM) is emerging as an unconventional manufacturing process of exceptional flexibility capable to fabricating any complex part without requiring expensive fixtures, tooling, mold or any other additional auxiliary with a very short lead time from design conceptualization to...
Article
Additive Manufacturing (AM) is a method of joining metal/non-metals or composites layer by layer using different energy sources. Among the various AM processes, laser-based powder bed fusion (LPBF) is very popular, in which geometrically complex structures can be manufactured directly from CAD models. One of the least investigated areas in LPBF is...
Conference Paper
Laser surface hardening of most of the industrial components require depth of surface modification in the range of 100-150 micron. Conventional laser surface hardening uses laser as a heat source to modify a particular area of the surface without melting in an inert gas environment. However, the hardened profile in this case shows peak hardness val...
Conference Paper
Selective Laser Melting process enables production of geometrically complex parts directly from CAD model by melting metal powders layer by layer. For successful building of parts, some auxiliary structures namely support structures are also built to ensure proper heat conduction from actual parts to be built to the base plate. Support structures a...
Conference Paper
One of the versatile additive manufacturing processes is laser based Selective Laser Melting (SLM) which allows to build complex intricate shapes directly from its three dimensional digital images. Layer by layer deposition and depending upon build orientations, SLM parts tends to be anisotropic in nature. Also non-uniformity in thermal loading acr...
Conference Paper
One of the most popular additive manufacturing processes among today’s manufacturing industries is Selective Laser Melting (SLM) in which very intricate shapes can be fabricated directly from its three dimensional digital design data by melting metal powders using laser. Layer by layer deposition of material about different build axes make SLM part...
Conference Paper
One of the most popular additive manufacturing processes is laser based direct metal laser sintering process which enables us to make complex three dimensional parts directly from CAD models. Due to layer by layer formation, parts built in this process tend to be anisotropic in nature. Suitable heat treatment can reduce this anisotropic behaviour b...
Chapter
An ergonomic study of manual material handling tasks in construction needs to address a number of manual material handling task-related problems such as pains in the back, shoulders and wrists, strain and sprain injuries, musculoskeletal disorders, severe fatigue and loss of energy of the workers and those acquired from improperly designed safety g...
Chapter
From ergonomic point of view, work capability, efficiency, and performance of the workers may substantially decrease as they involve themselves in critical man-machine interactions during construction-related manual material handling tasks. Therefore, to improve the existing ergonomic performance of the work system as a whole with respect to a give...
Article
Full-text available
This paper discusses the details of a study undertaken for biomechanical evaluation of a number of Manual Material Handling (MMH) tasks being carried out at a construction site in India. A comprehensive methodology involving a two dimensional dynamic biomechanical evaluation approach is developed for such construction MMH tasks involving carrying a...
Article
Globalised supply chains, volatile energy and material prices, increased carbon regulations, competitive and marketing pressure for environmental sustainability are driving supply chain decision makers to reduce carbon emissions. Enterprises face the necessity and the challenge of implementing strategies to reduce their supply chain environmental i...

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Projects

Projects (6)
Project
Indigenous development of Laser based Metal Additive Manufacturing facility with online monitoring and feedback control for consistent mechanical and metallurgical properties
Project
Laser Surface Treatment of Martensitic Stainless Steels
Project
The present work focuses on indigenous development of multi-axis CNC control system for laser shock peening applications