Vipul Kumar Gupta

GE Global Research · Additive Breakout Lab

Accurate identification and modeling of process maps in additive manufacturing remains a pertinent challenge. To ensure high quality and reliability of the finished product researchers rely on models that entail the physics of the process as a computer code or conduct laboratory experiments which are expensive and oftentimes demands significant log...

Oxide inclusions in stainless steel act as initiation sites for microvoids which result in significant effects on mechanical properties. In the case of additive manufacturing (AM) 316L stainless steel, oxide inclusions can nucleate during laser melting and remain in the solidified microstructure. This work is aimed at assessing whether extraneous o...

The evolution of nano-scale oxide inclusions in 316L austenitic stainless steel (SS) manufactured by laser powder bed fusion (L-PBF) was investigated. The parts were heat treated at different temperature for same time, the size, morphology and chemistry of oxide inclusions were characterized. After heat treatment, oxide inclusions were found be mai...

One of the key challenges of additive manufacturing is the identification of process maps to ensure high quality and reliability of the finished product. This typically requires running experiments which are expensive and usually require significant logistic and overheads. Physics based computational modeling and uncertainty quantification has show...

The origins of nano-scale oxide inclusions in 316 L austenitic stainless steel (SS) manufactured by laser powder bed fusion (L-PBF) was investigated by quantifying the possible intrusion pathways of oxygen contained in the precursor powder, extraneous oxygen from the process environment during laser processing, and moisture contamination during pow...

Single-track laser fusion were simulated using a heat-transfer-solidification-only (HTS) model and its extension with fluid dynamics (HTS_FD) model using a parallel open-source code, which included laminar fluid dynamics, flat-free surface of the molten alloy, heat transfer, phase-change, evaporation, and surface tension phenomena. The results illu...

A novel framework including experimental and model-based techniques saves time and enables the introduction of new alloys for additive manufacturing https://static.asminternational.org/amp/201910/16/

Artificial intelligence/machine learning in manufacturing and inspection: A GE perspective - Volume 44 Issue 7 - Kareem S. Aggour, Vipul K. Gupta, Daniel Ruscitto, Leonardo Ajdelsztajn, Xiao Bian, Kristen H. Brosnan, Natarajan Chennimalai Kumar, Voramon Dheeradhada, Timothy Hanlon, Naresh Iyer, Jaydeep Karandikar, Peng Li, Abha Moitra, Johan Reiman...

Iron-chromium-aluminum (FeCrAl) alloys are being investigated as cladding material for urania nuclear fuel in light water power reactors. One extraordinary attribute of the FeCrAl alloys is their resistance to attack by air and steam up to their melting point. It was of interest to study the kinetics of oxidation of FeCrAl from 800°C to 1300°C in a...

The computed tomography (CT) application presented herein aims at measuring cracks three dimensionally in a non-traditional fracture mechanics Superalloy 718 specimen exposed to supercritical CO2 (sCO2). Superalloy 718 is one material of choice for manufacturing components for Concentrated Solar Plant (CSP) units using sCO2 power cycle. To quantify...

A multi-functional aluminium alloy 7050 (AA7050) containing embedded Ni–Ti shape memory alloy particles to detect fatigue crack growth is proposed. The regions of intense strain near the tip of a growing fatigue crack cause nearby Ni–Ti particles to undergo a solid-state phase transformation from austenite to martensite, releasing a detectable acou...

Mechanistic understanding based on experimental measurements of grain and crack tip deformation at relevant length scales is critical for improvement of physics-based modeling of microstructurally-sensitive fatigue crack propagation and for the computationally-assisted design of more durable materials. In this study, single-crystal, bi-crystal, and...

Historically, the structural optimization of aerospace components has been done through geometric methods. A monolithic material is chosen based on the best compromise between the competing design limiting criteria. Then the structure is geometrically optimized to give the best overall performance using the single material chosen. Functionally grad...

Temperature dependence of fatigue crack formation and microstructure-scale growth from constituent particles in 7075-T651 and 7050-T7451 is quantified via load induced fracture surface marker-bands. Larger and more abundant particles in 7075-T651 lead to increased crack formation frequency and decreased life. Crack growth rates are similar between...

SEM-based electron backscattered diffraction (EBSD) measurements characterize constituent-particle nucleated fatigue crack path relative to local grain orientation and crack wake defect distribution for Al–Zn–Mg–Cu alloy 7050-T7451 stressed in moist air. Crack propagation is primarily transgranular; consisting of facets parallel to {1 0 0}, {1 1 0}...

SEM-based stereology in conjunction with electron backscattered diffraction established fatigue crack surface crystallography within the region from similar to 1 to 50 mu m of crack initiating particles in aluminum alloys, 7075-T651 and 7050-T7451, stressed in ambient moist-air and -50 degrees C dry-N(2) environments. Fatigue crack facets were para...

This paper describes a broad effort that is aimed at understanding the fundamental mechanisms of crack growth and using that understanding as a basis for designing materials and enabling predictions of fracture in materials and structures that have small characteristic dimensions. This area of research, herein referred to as Damage Science, emphasi...

A simple algorithm is developed and implemented to eliminate ambiguities, in both statistical analyses of orientation data (e.g., orientation averaging) and electron backscattered diffraction (EBSD) orientation map visualization, caused by symmetrically equivalent orientations and the wrap-around or umklapp effect. Using crystal symmetry operators...

Extended abstract of a paper presented at Microscopy and Microanalysis 2010 in Portland, Oregon, USA, August 1 – August 5, 2010.

A Laue X-ray diffraction pattern indexing scheme, similar to a method previously proposed for convergent beam and backscattered electron diffraction patterns, was implemented. Experimental diffraction patterns are compared with simulated templates corresponding to crystals of prescribed orientations. The orientation of a diffracting volume is deter...

The crack initiation sites and microstructure-sensitive growth of small fatigue cracks are experimentally characterized in two precipitation-hardened aluminum alloys, 7075-T651 and 7050-T7451, stressed in ambient temperature moist-air (warm-humid) and -50?C dry N2 (cold-dry) environmental conditions. Backscattered electron imaging (BSE) and energy...

Summary The wire mesh used to hold the catalyst in an ammonia converter vessel had shown cracking after use for 5 years. The environment was nitrogen and hydrogen gases at an operating temperature of 500-600°C. There was a thick blackish coating on the surfaces. Microstructural examination, magnetic property and microhardness measurements showed em...

Compact tension samples fatigue cracked within ultrahigh vacuum and humid air were examined using electron backscatter diffraction band contrast (i.e., pattern quality) maps obtained at the crack-wake. A protocol for relating changes in band contrast with the extent of plasticity (i.e., the cyclic plastic zone size, rcpz) as a function of environme...