Rajeev Gupta

Rajeev Gupta
North Carolina State University | NCSU

BTech, PhD

About

129
Publications
13,236
Reads
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2,107
Citations
Citations since 2017
75 Research Items
1616 Citations
20172018201920202021202220230100200300400500
20172018201920202021202220230100200300400500
20172018201920202021202220230100200300400500
20172018201920202021202220230100200300400500
Introduction
Dr. Rajeev Gupta’s research group focuses on understanding passivity, corrosion initiation and propagation mechanisms, structure/processing/property relationships, and surface electrochemistry using state-of-the-art material characterization and electrochemical techniques. The fundamental research is intended to be applied in the developing novel metallic materials, corrosion characterization techniques, material processing technologies and advanced coatings.
Additional affiliations
August 2020 - present
North Carolina State University
Position
  • Professor (Associate)
November 2014 - August 2020
University of Akron
Position
  • Professor (Assistant)
February 2013 - September 2014
Deakin University
Position
  • Research Academic
Education
August 2006 - May 2010
Monash University (Australia)
Field of study
  • Materials Engineering
July 2000 - July 2004
Indian Institute of Technology Kanpur
Field of study
  • Materials and Metallurgical Engineering

Publications

Publications (129)
Article
Nickel matrix composites reinforced with graphene exhibiting different morphology (i.e., shape and size) with varying content (0.5 and 1 wt.%) have been prepared using ball-milling and the spark plasma sintering technique. The graphene-based reinforcements used in this study were procured from different sources, processed using different techniques...
Article
Al alloys with far-from-equilibrium compositions and microstructures are reported to possess high corrosion resistance and strength. These alloys produced are by non-equilibrium processing techniques such as high-energy ball milling, sputtering, and ion implantation. Depending on the processing techniques and conditions, the microstructure of the a...
Article
Feedstock modified powders were produced by ball-milling commercial 316 L stainless steel powder and 1 wt.% additive (Cerium oxide–CeO2, lanthanum (III) nitrate hexahydrate–La(NO3)3.6H2O and chromium nitride–CrN). Laser-powder bed fusion (L-PBF) was performed on modified feedstock using 180, 200, and 220 W laser power. The influence of additives on...
Article
Nanocrystalline Al-Fe alloy, with uniform microstructure and high solid solubility of Fe, has been produced by high-energy ball milling. Cyclic potentiodynamic polarization tests revealed high pitting potential. Hardness and corrosion resistance of the Al-Fe alloy were higher than any commercial Al alloy. High hardness and corrosion resistance were...
Article
An Al-V alloy powder produced by high-energy ball milling has been cold sprayed on an AA2024-T3 substrate. The corrosion resistance of cold sprayed alloy, represented by the corrosion current density and pitting potential, was significantly higher than the substrate. Furthermore, a zero-resistance ammeter test revealed that the coating was anodic t...
Article
This article compares the corrosion behavior and hardness of an Al alloy (AA2024) produced by high-energy ball milling in air and high-purity Ar. The pre-alloyed AA2024 powder was milled in Ar and air atmospheres, and the produced powder was successfully consolidated to investigate the hardness and corrosion performance. Cyclic potentiodynamic pola...
Article
Full-text available
The applications of laser-powder bed fusion (LPBF), an emerging additive manufacturing (AM) technique, are rapidly growing in various industries. The superior and consistent mechanical and corrosion properties of LPBF-printed components are essential for engineering applications. The 316L stainless steel (SS) is an essential alloy with widespread a...
Article
Full-text available
The effect of V addition on the hardness and corrosion of aluminum alloy 2024 (AA2024) produced by high‐energy ball milling has been investigated. High‐energy ball milled alloys exhibited enhanced solid solubility of alloying elements and ultrafine grains. The addition of V improved the corrosion resistance of the AA2024 alloy, which was attributed...
Article
Carbon nanotubes (CNT) are integrated into 316L stainless steel (SS) powder feedstocks and 3D-printed using selective laser melting (SLM). Ball milling is used to disperse CNT clusters homogeneously onto the surface of 316L SS powders with minimal damage to the CNTs. Hardness increased by 35% and wear was reduced by 70% with the addition of 2 vol%...
Article
Characteristics of the passive film and the ability of an alloy to repassivate in any event of passive film breakdown control the corrosion. Studying the passive film has been of great interest since late 1836 when first-time iron was called altered iron. Significant progress in understanding the passive film composition and factors causing breakdo...
Article
Corrosion is a massive disaster in many sectors that caused the loss of billions of dollars. For example, it was reported that the total direct estimated cost of corrosion was about $ 276 billion in 1998 in the US, which is 3.1% of the nation’s GDP. Therefore, a necessity to develop methods to overcome this challenge arose in the last few decades....
Article
Additive manufacturing (AM) is an emerging technology that can build 3d-component in a single step via the layer-by-layer process. Selective laser melting (SLM) is a popular powder bed fusion (PBF) – AM technique that involves rapid heating and cooling cycles with broad temperature gradients and complex thermal history. Moreover, the SLM components...
Article
The effect of age-hardening on microstructure, hardness, and corrosion of an Al-5at.%V alloy, produced using high-energy ball milling and subsequent cold compaction, has been investigated. The alloy exhibited a grain size below 100 nm and extremely high solid solubility of V in Al (3.1 at.%). The age-hardening was carried out at 150, 200, and 250 ℃...
Article
Binary Al-5M alloys, containing 5 at.% alloying element (M: Cr, Si, Nb, Mo, and V), have been produced by high-energy ball milling and subsequent spark plasma sintering. X-ray diffraction analysis indicated the solid solubility of the alloying elements to be several orders of magnitude higher than that predicted by the phase diagram. The elastic mo...
Article
Multi-principal element alloys (MPEAs), inclusive of high entropy alloys (HEAs), continue to attract significant research attention owing to their potentially desirable properties. Although MPEAs remain under extensive research, traditional (i.e. empirical) alloy production and testing are both costly and time-consuming, partly due to the inefficie...
Article
Al-xV alloys (x = 2 at.%, 5 at.%, 10 at.%) with nanocrystalline structure and high solid solubility of V were produced in powder form by high-energy ball milling (HEBM). The alloy powders were consolidated by spark plasma sintering (SPS) employing a wide range of temperatures ranging from 200 to 400°C. The microstructure and solid solubility of V i...
Article
Supersaturated solid solutions of Al and corrosion-resistant alloying elements (M: V, Mo, Cr, Ti, Nb), produced by non-equilibrium processing techniques, have been reported to exhibit high corrosion resistance and strength. The corrosion mechanism for such improved corrosion performance has not been well understood. We present a fundamental underst...
Preprint
Full-text available
Multi-principal element alloys (MPEAs), inclusive of high entropy alloys (HEAs), continue to attract significant research attention owing to their potentially desirable properties. Although MPEAs remain under extensive research, traditional (i.e. empirical) alloy production and testing is both costly and time-consuming, partly due to the inefficien...
Article
Full-text available
Additive manufacturing (AM) is an emerging technology to produce engineering components. However, the major challenge in the practical application of AM is the inconsistent properties of additively manufactured components. This research presents a strategy of feedstock modification to improve the corrosion performance of selective laser melted (SLM...
Article
The influence of high energy-ball milling (HEBM) on corrosion and hardness of age hardening aluminum alloys was investigated. Nanocrystalline age hardening (AA2024, AA6061 and AA7075) alloys were produced by HEBM of pre-alloyed powder and subsequent cold compaction under uniaxial pressure of 3 GPa. Cyclic potentiodynamic polarization and immersion...
Article
Full-text available
Carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) with exceptional mechanical, thermal, chemical, and electrical properties are enticing reinforcements for fabricating lightweight, high-strength, and wear-resistant metal matrix composites with superior mechanical and tribological performance. Nickel–carbon nanotube composite (Ni-CNT) and ni...
Article
AA5083 alloys with V additions were produced in the powder form by high-energy ball milling and consolidation by spark plasma sintering and cold compaction. X-ray diffraction and energy dispersive X-ray spectroscopy analysis indicated the formation of supersaturated solid solution and grain refinement below 100 nm. Corrosion behavior was investigat...
Article
The effect of milling time and speed on solid solubility of V in Al and grain refinement was studied. High-energy ball milling was used to produce Al-xV (x = 2, 5, and 10 at.%) alloys at milling speeds of 280 and 350 RPM. The ball-milling time was varied from 10 to 100 hours. The ball-milled alloys were consolidated under uniaxial pressure of 3GPa...
Article
The multi-walled carbon nanotubes (CNTs) reinforced nickel matrix nanocomposites (Ni-CNT) have been processed via ball milling followed by spark plasma sintering (SPS) process. The CNT content in these nanocomposites has been varied from 0.5 to 2 wt/% (approximately from 2 to 8 vol.%) to study their effect on the dispersion, microstructure, and mec...
Article
The graphene nanoplatelet (GNP) reinforced nickel matrix composites (Ni-GNP) have been processed using two different ball milling approaches, viz, dry ball milling (DM) and solution ball milling (SBM), followed by consolidation using spark plasma sintering (SPS) technique. The composites were reinforced with varying GNP concentration (0.5 to 2 wt.%...
Article
Full-text available
A compositionally complex alloy was designed, consisting of equiatomic concentrations of four low-cost commodity elements (Al, Fe, Mn, and Si). The alloy was characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy. The corrosion of the AlFeMnSi alloy, as evaluated using potentiodynamic polarization tests and electr...
Article
Full-text available
Recent exploration of multi-principal-element alloys (MPEAs), which include the so-called high-entropy alloys, has revealed hitherto unreported properties and phenomena arising from investigation of broader compositional space. Herein, a low cost and lightweight alloy (equiatomic AlFeMnSi) is presented that exhibits exceptional corrosion resistance...
Article
Full-text available
The influence of mechanical alloying (MA) and spark plasma sintering (SPS) processing parameters on the microstructure, magnetic and mechanical properties of Finemet (Fe 73.5 Cu 1 Nb 3 Si 13.5 B 9) type alloys was investigated. Finemet alloy powder was obtained via mechanical alloying of elemental powders for 30 h, 60 h, 90 h, and 120 h with ball t...
Article
Full-text available
The influence of different Mg concentrations on the mechanical properties and microstructure of an Al-Li alloy was studied. The highest Mg content was up to 1.1 wt.%. To the best of the authors knowledge, alloys with such a high Mg content has not been reported in the literature. The mechanical properties, yield strength and elongation at failure,...
Chapter
The influence of variations in the titanium carbide (TiC) content employed during spark plasma sinteringSpark plasma sintering (SPS) (SPS) of nickel–titanium carbide (Ni-TiC) composites on its microstructureMicrostructureand mechanical propertiesMechanical properties has been investigated systematically. Mechanical alloyingMechanical alloying (MA)...
Chapter
Nickel-Titanium-Graphite-based metal matrix compositesMetal matrix composite (MMC) (MMC) with in situ formed titanium carbide (TiC), as well as graphite (C) reinforcement in the nickel (Ni) metal matrix, were processed using mechanical alloyingMechanical alloying (MA)(MA) and spark plasma sinteringSpark plasma sintering (SPS) (SPS). The objective o...
Article
Full-text available
In this study, a compact cold sprayed (CS) Ti coating was deposited on Mg alloy using a +high pressure cold spray (HPCS) system. The wear and corrosion behavior of the CS Ti coating was compared with that of CS Al coating and bare Mg alloy. The Ti coating yielded lower wear rate compared to Al coating and Mg alloy. Electrochemical Impedance spectro...
Article
The corrosion, microstructure, and hardness of nanocrystalline AA5083 were compared to that of conventional AA5083-H116 and consolidated gas atomized powder. The nanocrystalline AA5083 was produced by consolidating high-energy ball milled gas atomized powder with two methods: cold compaction and spark plasma sintering. Electrochemical impedance spe...
Article
Full-text available
Titanium carbide (TiC) reinforced nickel (Ni) matrix composites were processed via mechanical alloying (MA) followed by spark plasma sintering (SPS) process. Mechanical alloying has gained special attention as a powerful non-equilibrium process for fabricating amorphous and nanocrystalline materials, whereas spark plasma sintering (SPS) is a unique...
Article
In this work, nine nanocrystalline binary Mg alloys synthesized by high energy ball milling. The compositions, Mg-5wt.%M (M- Cr, Ge, Mn, Mo, Ta, Ti, V, Y, Zn) were milled with an objective of achieving non-equilibrium alloying. The milled alloys were consolidated via cold compaction (CC) at 25 C and spark plasma sintering (SPS) at 300 C. X-ra...
Article
In this research, cold sprayed Al coating layer on AZ31B Mg alloy was coated with cold sprayed Ti and Ta/Ti coatings, which noticeably reduced the wear rate of Al coated Mg alloy. Electrochemical corrosion tests and infinite focus 3D measurement results revealed that the high surface activity of commercially pure-Al coating, diffusion-controlled re...
Article
Full-text available
Intergranular corrosion (IGC) and pitting transition caused by grain boundary β-phase saturation of aluminum alloy AA5083 sensitized at 150 °C was investigated in 3.5 wt% NaCl solution. The change in the localized corrosion mechanism from IGC to pitting was studied by microstructural and electrochemical analysis, where IGC was found to be the prima...
Article
Ti and Ta/Ti coatings were successfully applied on AZ31BMg alloy using high pressure cold spray process. These coatings (particularly Ta/Ti coating) with high hardness lowered the wear rate of AZ31BMg alloy. In-vitro bioactivity test, infinite focus 3D measurement and EDS results revealed that the calcium-phosphate (Ca–P) compounds nucleation and g...
Article
Ni-Ti-C metal matrix composites (MMC) with in situ formed, homogeneously distributed titanium carbide (TiC), as well as graphite (C) reinforcement in nickel metal matrix, were synthesized using Mechanical Alloying (MA) followed by Spark Plasma Sintering (SPS). The main objective of this research is to consolidate Ni-Ti-C MMCs with varying the C/Ti...
Article
The effect of reactive air aluminizing (RAA) on the high temperature oxidation behavior of the H230 superalloy is studied at 850 °C for 600 hours. Mass gain values are measured and microstructure is studied by XRD, SEM, and EDX. Post oxidation mass gain for the aluminized H230 is reduced compared to wrought H230. The RAA process lead to formation o...
Article
Full-text available
The influence of spark plasma sintering (SPS) temperature on microstructure, hardness and corrosion behavior of a high-energy ball milled Mg-10 wt% Al alloy was investigated in this work. The holding time and sintering pressure for SPS were kept constant while varying the sintering temperature from 200 to 350 °C. The grain size and microstructure w...
Article
Full-text available
Commercial aluminum alloys exhibit localized corrosion when exposed to environments containing aggressive anions. Alloying of Al with specific elements (M: Cr, Mo, V, Nb, etc) using non-equilibrium processing techniques has been reported to result in significantly improved corrosion resistance due to the formation of a supersaturated solid solution...
Preprint
A new class of compositionally complex alloy, consisting of equiatomic concentrations of Al, Fe, Mn and Si is reported. The alloy was characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy. Corrosion behavior of the AlFeMnSi alloy, as evaluated using potentiodynamic polarization tests and electrochemical impedance...
Article
Full-text available
In metallurgy, titanium has been a staple for biomedical purposes. Its slow toxicity and alloying versatility make it an attractive choice for medical applications. However, studies have shown the difference in elastic modulus between titanium alloys (116 GPa) and human bone (10–40 GPa), which contributes to long term issues with loose hardware fix...
Article
Full-text available
The native surface oxide upon a single phase low-density compositionally complex alloy (CCA), AlTiVCr, was studied herein-owing to its exceptionally high aqueous corrosion resistance. The nature of the native surface oxide/surface film was elaborated in the context of corrosion resistance, based on results from electrochemical testing, secondary io...
Article
Due to their excellent oxidation resistance and creep resistance at elevated temperature, alumina-forming austenitic (AFA) stainless steels have emerged as potential alloys for high-temperature applications. In this study, a reactive air aluminizing method was used to aluminize the surface of AFA 25 stainless steel. The high-temperature oxidation b...
Article
The influence of various amounts of Zn addition on the microstructure and associated intergranular corrosion of Al-2.8Cu-1.7Li-0.4Mg-0.3Mn-0.12Zr alloys was studied using transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy, and corrosion and electrochemical techniques. The added Zn was incorporated into the precipitat...
Article
In present study, nanocrystalline Mg-xAl (x= 0, 5, 10 and 20 wt.%) alloys were produced via high-energy ball milling (HEBM) followed by compaction under uniaxial pressure of 3 GPa at room temperature. The produced alloys were subjected to heat treatment (HT) for 1 h at various temperatures ranging from room temperature to 425 ºC. The microstructure...
Article
Plasma electrolytic oxidation (PEO) was developed as a bond coat for air plasma sprayed (APS) nanostructure ZrO2 as top coat to enhance the corrosion resistance and antibacterial activity of Mg alloy. Corrosion behavior and antibacterial activities of coated and uncoated samples were assessed by electrochemical tests and agar diffusion method towar...
Article
The IGC behaviour, OCP and microstructure of AA1460 (Al-3.12Cu-2.14Li-0.12Sc-0.12Zr, in wt.%), following HT1 (heat treatment without predeformation) and HT2 (heat treatment with predeformation) tempers were investigated. Both δ′ (Al 3 Li) and T 1 (Al 2 CuLi) phases were precipitated within grains during heat treatment, while T 1 phase also precipit...
Article
Plasma electrolytic oxidation (PEO) coatings in the aluminate-silicate-based mixture electrolyte solution with different duty cycles were successfully applied on Mg alloy. The corrosion behavior of the samples was evaluated by water contact angle test, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and immersion tests. H...
Article
An Al-5 at. pct Cr alloy was produced by high-energy ball milling at liquid nitrogen temperature followed by consolidation using equal-channel axial extrusion at 200 °C, 300 °C and 450 °C. The microstructure and corrosion response were compared with a cast alloy of the same composition. Rather than the intermetallics expected by the phase diagram a...
Article
Nanocrystalline Al-5at.%V and Al-5at.%Ni alloys, prepared by high-energy ball milling and subsequent consolidation under uniaxial pressure of 3 GPa, were subjected to isothermal heat treatment for one hour at various temperatures—ranging from 100 to 614 °C. Grain growth, solid solubility of the alloying elements, and formation of additional phases...
Article
Full-text available
Development of ultra-high strength and corrosion-resistant aluminum (Al) alloys is demonstrated by a combination of suitable alloying elements and processing technology able to cause extended solid solubility and nanocrystalline structure. Binary Al-transition metal (M: Cr, Ni, Mo, Si, Ti, Mn, V, Nb) alloys, produced by high-energy ball milling and...
Article
The corrosion of metallic materials in a given environment depends on the microstructure stemmed from the concurrent influence of the composition, production route, thermomechanical processing, and service conditions. Microstructures and therefore the properties of the alloys produced via high-energy ball milling are known to be significantly diffe...
Chapter
Aluminum exhibits excellent corrosion resistance in the pH range of 4–8 due to the presence of a thin “passive film” upon the metal surface [1–9]. Breakdown of the passive film caused by several metallurgical (defects, impurities, secondary phases etc.) and environmental (halide ions, high or low pH, temperature) factors leads to the significant lo...
Chapter
Alloying of elemental blends achieved through high-energy ball milling (HEBM) is referred to as mechanical alloying (MA), which is a solid-state powder processing technique involving the repeated deformation, fracture and welding of powder particles [1–4]. This technique was originally developed to produce oxide-dispersion strengthened (ODS) nickel...
Chapter
Nanocrystalline metallic materials [1–3] produced by the high-energy ball milling (HEBM) [4] are reported to be much stronger and apparently less ductile than conventional coarse grained materials. This difference in the properties is attributed to the unique grain structure, defects, defect activity and the arrangement of such features in nanocrys...
Chapter
High-energy ball milling (HEBM) of Al and Al based alloys results in the nanocrystalline alloys in the form of powder, which subsequently needs to be consolidated for engineering applications, as well as for the investigation of associated properties. Consolidation of HEBM nanocrystalline alloy powders is not a trivial task. High mechanical strengt...
Chapter
High-energy ball milling (HEBM) is a non-equilibrium processing techniques that imparts extended solid solubilities of alloying elements and grain refinement to the nanoscale level, this results in a thermodynamically metastable system. Such a metastable system can be prone to grain growth and decomposition of the solid solution, with elevated temp...
Chapter
High-energy ball milled Al alloys have demonstrated extraordinary properties due to grain refinement to the nanoscale, and increased solid solubility of alloying elements. For example, the compressive yield strength of 1200 and 1105 MPa was observed in Al-Fe [1] Al-Cr alloys [2], both prepared via HEBM followed by consolidation. The specific compre...
Article
The paper presents a new concept of metallic materials containing inhibitor, able to inhibit corrosion as it ini-tiates. Al particles with uniformly dispersed sodium chromate (0.5–20 wt%) were produced by high-energy ball milling followed by cold compaction. Cyclic potentiodynamic polarization tests and surface analysis after con-stant immersion te...
Article
The corrosion behavior of Al–5 at.% Cr, Al–5 at.% Si, Al–5 at.% Mo and Al–5 at.% Ti produced via casting and Al–5 at.% Cr produced by high-energy ball milling and subsequent consolidation by cold pressing was studied using potentiodynamic polarization and surface analysis following constant immersion tests. Alloys were characterized using a scannin...
Book
This book presents a comprehensive overview of the nanocrystalline Al based alloys as prepared using high-energy ball milling (HEBM). It discusses the influence of HEBM parameters on grain refinement and examines methods for the consolidation of nanocrystalline Al powders; further, it reviews the effects of various processing parameters on the fina...
Research
Full-text available
Nanocrystalline Al-5at.%Cr alloy produced by high-energy ball milling has been reported to exhibit superior mechanical properties and corrosion resistance compared to any conventional alloy [1]. The exceptional properties of these alloys were attributed to the grain refinement to nano-scale, increased solid solubility and homogeneously dispersed fi...
Article
Full-text available
An approach to achieving the ambitious goal of cost effectively extending the safe operation life of energy pipeline to 100 years is the application of health monitoring and life prediction tools that are able to provide both long-term remnant pipeline life prediction and in-situ pipeline condition monitoring. A critical step is the enhancement of...
Article
Excursion of cathodic protection (CP) potential from the designed 'safe' CP level due to various forms of electrical interference signals are observed rather frequently in industrial applications, in particular in the pipeline industry, however the influence of such potential fluctuations on the corrosion behaviour of steel under CP conditions does...
Chapter
The use of Al-alloys is limited in many applications due to a dramatic deterioration of the corrosion properties with any effort made to increase the strength. The hardening phases, uniformly distributed fine intermetallics, act as electrochemical heterogeneities and promote galvanic interactions, thus causing localized corrosion. The chemical comp...
Chapter
The use of Al-alloys is limited in many applications due to a dramatic deterioration of the corrosion properties with any effort made to increase the strength. The hardening phases, uniformly distributed fine intermetallics, act as electrochemical heterogeneities and promote galvanic interactions, thus causing localized corrosion. The chemical comp...