Suraj Persaud

Suraj Persaud
Queen's University | QueensU · Department of Mechanical and Materials Engineering

Ph.D.

About

41
Publications
3,461
Reads
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460
Citations
Additional affiliations
January 2018 - present
Queen's University
Position
  • Professor (Assistant)
September 2015 - December 2017
Canadian Nuclear Laboratories
Position
  • Researcher
Education
September 2005 - September 2015
University of Toronto
Field of study
  • Chemical Engineering

Publications

Publications (41)
Article
The effect of alloy composition on the dealloying susceptibility of Ni- and Fe-based alloys is studied in near-boiling caustic solutions. A comprehensive comparison of the alloys is performed using electrochemical measurements and nanoscale characterization to evaluate dealloying behaviour. Results indicate a general increase in dealloying resistan...
Article
This study investigates corrosion of Fe-(Cr)-Ni model alloys in eutectic molten chloride salt mixtures that broadly simulate the heat transfer circuits of molten salt cooled nuclear reactors. The primary focus is impurity-driven corrosion and selective dissolution of electrochemically reactive element(s) (dealloying), which are known degradation mo...
Article
The microstructures of copper (Cu) materials were investigated by electron backscatter diffraction, showing that electrodeposited (ED) Cu has a homogenous polycrystalline microstructure, while cold spray (CS) Cu has a heterogeneous microstructure with varying grain size, pores, and interfacial splat regions. The corrosion rate was examined by corro...
Article
This study investigates dealloying of Fe-(Cr)-Ni model alloys in molten chloride salts that simulate the heat-transfer circuits of molten salt nuclear reactors. Classical dealloying with porosity formation is observed as the dominant form of corrosion at low homologous temperature, and the usual, fundamental, geometric parting limit for dealloying,...
Article
The crystal structure of the hydride induced by water quenching in hydrided Zr-2.5Nb pressure tube was identified by a combined approach of synchrotron x-ray diffraction and TEM nano-beam electron diffraction, coupled with density functional theory. It has been found that the hydrides experimentally characterized have the same face-centered tetrago...
Article
A failure analysis was performed on an alloy C-276 pull rod which underwent unexpected brittle, intergranular fracture after exposure to 280°C-300°C aqueous solutions designed to replicate secondary side environments in nuclear energy systems: Pb-containing alkaline (pH300°C 8.5-9.5), and sulfate-containing acidic solutions (pH280°C 3-5). The compo...
Article
Internal oxidation of Ag-xIn alloys (x = 10, 13, 16 at%) was studied in an air atmosphere at a relatively low homologous temperature (240 °C), where lattice diffusion is negligible. After exposure, metallic Ag nodules were present on the surfaces of all alloys, expelled to relieve stress due to internal oxidation, confirming that such coarse morpho...
Article
The oxidation behavior of a 9Cr-4.5Al ODS steel in 600℃ supercritical water with 200 ppb dissolved oxygen was investigated with and without a pre-oxidation heat treatment. In general, results suggest that all samples follow the “available space model” oxidation mechanism as exposure time is extended. Based on the microstructural analysis, it is fou...
Article
30% cold worked (CW) carbon steel tensile specimens were exposed to 360 °C air and hydrogen environments (2 MPa H2 and 20 MPa H2) under an applied load to produce intergranular creep cracking. In this study, cutting-edge microscopy techniques were applied to characterize cracking on multiple length scales and in three-dimensions. The objective was...
Article
The preparation of TEM samples using focused-ion beam (FIB) techniques allows for characterization of electron-transparent site-specific areas, such as oxide-metal interfaces and crack tips, leading to improved understanding of material degradation mechanisms. Using conventional FIB techniques to prepare zirconium alloy TEM samples results in the p...
Conference Paper
In-service inspections of Zr-2.5Nb pressure tubes may reveal blunt flaws such as fretting wear or crevice corrosion marks. These flaws pose no immediate threat to the integrity of the pressure tube but may be potential fatigue crack initiation sites. An understanding of the effect of the coolant environment, specifically on fatigue crack initiation...
Conference Paper
The mechanical properties of zirconium alloys are affected by the presence of hydrides. The strain fields around hydrides, which are affected by the size, orientation, and hydride phase, are believed to influence the apparent hysteresis between solubility limits on heating and cooling. TEM characterization of dislocation fields near hydrides in Zir...
Conference Paper
Advanced electron microscopy and surface science techniques were applied to characterize inter- and intragranular oxidation in Ni–Fe–Cr alloys after exposure to 480 °C hydrogenated steam. Intragranular internal Fe and Cr oxidation was observed in all cases while intergranular oxidation, exclusively external or penetrative, varied depending on the C...
Conference Paper
The primary heat transport system of modern CANDU® (CANDU is a registered trademark of Atomic Energy of Canada Limited) reactors uses A106B piping (i.e., feeder pipes). Feeder cracking has only affected tight-radius bends at outlet feeders (higher temperature), and cracking is limited to regions with high residual stress suffering from wall-thinnin...
Conference Paper
Full-text available
Thermal energy release and hydrogen generation due to breakaway oxidation of Zr fuel cladding materials are of concern in accident scenarios involving extreme temperature increase (up to 1200 °C). As a result, potential accident tolerant fuel cladding (ATFC) materials and coatings are being investigated. Physical vapor deposited CrN coatings are co...
Conference Paper
Aggressive aqueous environments (Pb, S, pH extremes) used in laboratory tests have been shown to induce stress corrosion cracking (SCC) in Ni–Fe–Cr alloys. These conditions are used to simulate the extremes of secondary side crevice environments that are unlikely to occur under normal operating conditions but laboratory testing can still be used to...
Article
Stress corrosion cracking (SCC) usually initiates at locally compromised surface regions, and ultimately at nanoscale precursor sites. The ability to identify such sites would be instrumental in predicting SCC failure and developing proactive mitigation strategies. Modern microscopy capabilities allow for the requisite micro-to-atomic scale analysi...
Article
Stress corrosion cracking (SCC) of Alloy 800 was induced in 330 °C Pb-caustic solution (pH330°C 9.5). These laboratory tests simulated extreme crevice environments in nuclear plants, but do not occur under normal operating conditions. Atom probe tomography (APT) was used to examine crack tips, a powerful but scarcely used technique for this applica...
Article
Environmentally assisted cracking (EAC) initiation tests were carried out by subjecting Alloy 800 tensile specimens to 0.55 mol/kg SO4²⁻ solution, pH280°C 3, at 280 °C using slow rise-time cyclic loading and in-situ crack detection. EAC, intergranular corrosion (IGC), and pitting were observed. Transmission electron microscopy analysis revealed Ti-...
Article
Alloy 800 was exposed to a 330 °C Pb-containing, mildly caustic (pH330°C 9.5) environment producing SCC. High resolution analytical TEM characterization of crack tips provided evidence to elucidate the Pb-caustic SCC mechanism and highlight a continuum of classical caustic SCC, facilitated at lower pH by the presence of Pb. Successive regions of Ni...
Article
To evaluate the beneficial effects of intergranular carbides on inhibiting stress corrosion cracking (SCC), Alloy 600 samples in the thermally-treated (TT) and solution-annealed (SA) conditions were analyzed after exposure to 480 °C hydrogenated steam. Intergranular oxidation was observed in both samples, along with diffusion-induced grain boundary...
Article
Internal oxidation in Alloy 600 (Ni–16Cr–9Fe) involves the inward diffusion of O, which preferentially reacts with solute elements (e.g. Cr, Fe) forming internal oxide precipitates. In this work, the internal oxidation process and its resultant metal-oxide heterostructures are systematically analyzed in 3D at the finest length scales, using atom pr...
Article
Alloy 800 was exposed to 480 °C hydrogenated steam with conditions maintained at an oxygen partial pressure well below the dissociation pressure of NiO. Oxidation phenomena in Alloy 800 were investigated using high resolution electron microscopy techniques. Limited oxygen penetration was detected at grain boundaries while extensive internal oxidati...
Article
Alloy 600 (Ni-16Cr-9Fe) and Alloy 800 (Fe-35Ni-23Cr) were exposed to simulated primary water at 315 °C. Oxidation phenomena were studied using high resolution electron microscopy. Extensive intergranular oxidation was observed in Alloy 600. In Alloy 800, only shallow intergranular oxygen penetration was detected. The mechanism of intergranular embr...
Article
The following is a review of the accumulated literature over the past 20 years for oxidation in Ni-Fe-Cr alloys exposed to 400°C to 500°C hydrogenated steam. Hydrogenated steam at temperatures of 500°C and below is considered to simulate 300°C to 360°C deaerated water often used in the primary circuit of nuclear power plants. Alloy 600 (Ni-16Cr-9Fe...
Article
Alloy 690 was exposed to a hydrogenated steam environment at 480 degrees C and 1 bar, considered to simulate primary water in a pressurized water reactor. The possibility of internal oxidation in Alloy 690 was evaluated and the likely relevance to SCC in primary water is discussed. Initial surface imaging revealed intragranular metallic Ni nodules,...
Article
Electrochemical measurements were made on Ni, Alloy 600, and Alloy 800, immersed in acid sulfate solutions at 315 °C. For pure Ni, adding sulfate in relatively small concentrations to solutions containing only chloride ions resulted in significantly increased current density in the anodic range and a sharp drop in polarization resistance, suggestin...
Article
Alloy 82 dissimilar weld joints between carbon steel and Alloy 600 were exposed to a simulated primary water environment consisting of hydrogenated steam at 480 degrees C and 1 bar. Dilution due to mixing from the parent materials to the weld was significant, particularly in the root where there was Fe enrichment (35 at.%) and Cr depletion (10 at.%...
Article
Alloy 600 in the solution annealed (SA) and thermally treated (TT) conditions was exposed to a hydrogenated steam environment considered to simulate primary water in pressurized water reactors. The likely susceptibility to primary water stress corrosion cracking (PWSCC) was evaluated using the internal oxidation model. A FIB was used to extract cro...
Article
Alloy 800 (Fe-21Cr-33Ni) has been found susceptible to cracking in acid sulfate environments, but the mechanism is not well understood. Alloy 800 C-ring samples were exposed to an acid sulfate environment at 315 °C and cracks were found with depths in excess of 300 μm after 60 hours. Preparation of a TEM sample containing crack tips is challenging,...
Article
Several studies have shown the influence of cold work on stress corrosion cracking (SCC). While these studies usually consider cold work as a homogeneous effect, the presence of grain boundaries and other crystalline defects results in local strain concentrations that are inhomogeneously distributed within the microstructure. In this work, local st...
Conference Paper
A mechanistic study was done on Alloy 600 exposed to a hydrogenated steam environment considered to simulate primary water conditions of PWR and CANDU reactors. Alloy 600, a Ni-Fe-Cr alloy, is used in the primary circuit of nuclear reactors and has been found susceptible to primary water stress corrosion cracking (PWSCC), even in highly reducing co...
Conference Paper
Full-text available
Alloy 600 and Alloy 800 are Ni-Fe-Cr alloys used in nuclear steam generators. Sulfate is an impurity found in faulted secondary side water that can accumulate in crevices in the acidic-to-neutral pH range, possibly resulting in acid sulfate stress corrosion cracking. Electrochemical measurements were done on Alloys 600 and 800 exposed to acid sulfa...