Characterization of Minerals, Metals and Materials: Characterization of Corrosion Resistance
Sponsored by: TMS Extraction and Processing Division, TMS: Materials Characterization Committee
Program Organizers: Jian Li, CanmetMATERIALS; Mingming Zhang, Baowu Ouyeel Co. Ltd; Bowen Li, Michigan Technological University; Sergio Monteiro, Instituto Militar de Engenharia; Shadia Ikhmayies, The University of Jordan; Yunus Kalay, Middle East Technical University; Jiann-Yang Hwang, Michigan Technological University; Juan Escobedo-Diaz, University of New South Wales; John Carpenter, Los Alamos National Laboratory; Andrew Brown, Devcom Arl Army Research Office
Wednesday 2:00 PM
February 26, 2020
Room: Theater A-5
Location: San Diego Convention Ctr
Session Chair: Ramasis Goswami, Naval Research Laboratory; Donato Firrao, Politecnico di Torino
2:00 PM
Characterization of Corrosion Product Deposits on Fuel Cladding Surface Under Various Heat Flux Conditions: Yunju Lee1; Junhyuk Ham1; Seung Chang Yoo1; Ji Hyun Kim1; 1UNIST
Axial Offset Anomaly (AOA) is a serious concern in several Pressurized water reactor power plants. Essentially, AOA is caused by deposition of a sufficient amount of boron in fuel crud deposits mostly found on the upper region of the fuel assembly. The crud deposition and boron accumulation are influenced by chemical and thermal-hydraulic behavior of water near fuel cladding surface. To predict the effect of crud deposition, crud deposition mechanism should be investigated, considering structural and chemical composition of crud layer. However, there is no detail study to investigate the changes in porosity and chemistry of crud in different heat flux conditions.In this study, simulated crud deposition experiments were performed in three different heat flux conditions. To investigate the effect of heat flux on the structure and chemistry of CRUD, the chemical composition of corrosion product, especially boron concentration, of the three samples were compared.
2:20 PM
Effect of Dual-phase Stabilization via Varying Ti/Nb Ratios on the Pitting Behavior of AISI 347 Welds: Amandeep Shahi1; Dikshant Malhotra1; 1SLIET, Longowal
Gas tungsten arc welding process was used to fabricate different multi-pass and multi-layer weld pads comprising of combinations of AISI 347 (Nb based) and AISI 321 (Ti based) solid fillers so as to obtain different weld surfaces with varying Ti/Nb ratios. These surfaces were examined for their pitting behavior using electrochemical technique, EPMA-WDS analysis for chemical composition and XPS depth profiling of passive films. Austenitic stainless steel welds with Ti/Nb ratio of 0.29 exhibited maximum pitting potential of 380.5 mV as compared to sole Nb weld with 260.4 mV. The concentration profiles of oxygen across different weld surfaces indicate that effective passive film thickness values for sole Nb and Nb weld stabilized with Ti/Nb ratio of 0.29 were calculated to be 7.23 nm and 8.81 nm respectively. This study indicates that Ti addition upto 0.15 wt % in Nb weld can significantly enhance its pitting resistance.
2:40 PM
Effects of Cooling Rate and Ti Addition on Microstructure, Mechanical Properties and Corrosion Characteristics of Laser Deposited Ti-6Al-4V Alloy: Olawale Fatoba1; Esther Akinlabi2; Stephen Akinlabi2; Fredeick Mwema2; 1Kent State University; 2University of Johannesburg
Materials solution to premature failures induced by corrosion and wear phenomena is simply the fabrication of coatings with superior chemical and mechanical properties than the parent material. The quality of deposited coatings depends on the melting, cooling and solidification of the melt pool. This paper focuses on the effect of hybrid coatings Al-Cu-Ti/Ti-6Al-4V composite using laser metal deposition (LMD) technique. The cross-sectional view of the cladded layer showed a uniform crack free surface due to optimized parameters which led to the refinement of the coatings. The hardness of the coated samples was enhanced significantly. Moreover, the coated samples showed enhanced corrosion resistance in 5M NaCl environment compared to the base metal. Decreased content of aluminium and increase amount of titanium favour the chemical performance of the composite thereby enhancing the mechanical and corrosion properties. Genetic Algorithm (GA) and COMSOL multi-physics models were used to validate the experimental results.
3:00 PM
The Effect of Radiation Damage and Radiolysis on the Corrosion of SiC with and without Corrosion-mitigation Coatings: Peter Doyle1; Takaaki Koyanagi2; Caen Ang1; Yutai Kato2; Steven Zinkle1; David Carpenter3; Stephen Raiman2; 1University of Tennessee; 2Oak Ridge National Laboratory; 3Massachusetts Institute of Technology
Due to favorable high temperature strength and corrosion resistance, radiation damage resistance, and adequate mechanical properties, SiC is a leading candidate to replace Zr-based alloys as accident-tolerant fuel cladding material for light water reactors. However, SiC does not form a passivating oxide in liquid water due to the dissolution of SiO2. To evaluate the operational viability of SiC, monolithic and ceramic matrix composite (CMC) SiC was exposed to PWR water chemistry at 300°C in the MIT nuclear reactor water loop in the presence of neutron and gamma flux, gamma flux, and only coolant (~127 days, 0.5-1 dpa). Coatings of monolithic Cr, monolithic TiN, and multilayer Cr/CrN on SiC were also included to evaluate the effectiveness of corrosion-mitigation. SiC was found to corrode acceptably in all conditions, with elevated mass loss in the gamma and neutron flux conditions. Mixed effectiveness of the coatings in mitigating SiC corrosion was observed.
3:20 PM Break
3:35 PM
Measuring the Thermal Conductivity of Molten Salts Using a Frequency-domain Hot-wire Technique: Andrew Zhao1; Matthew Wingert1; Yasuhiro Kodera1; Stephen Obrey2; Javier Garay1; 1University of California, San Diego; 2Los Alamos National Laboratory
Next generation energy technologies, such as concentrated solar-thermal power and nuclear power, require high temperature molten salts to be used as heat transfer fluids. The thermal properties of molten salts are difficult to measure due to their high melting points and reactivity. Time-domain or steady-state measurements are traditionally used to measure the thermal conductivity of molten salts; however, there is a large spread in experimental values and disagreement in their temperature dependence, possibly due to convection. We present a novel frequency-domain, hot-wire technique designed to measure molten and reactive materials at high temperature and to support the development of heat transfer fluids. By operating in the frequency-domain, we can lower the thermal penetration depth below 100 micrometers and minimize convection. We provide the first frequency-domain measurements of molten sodium nitrate, potassium nitrate, and their mixture up to 500°C and discuss the relationship between their liquid structure and thermal conductivity.
3:55 PM
Investigation of Stress Corrosion Crack Initiation Sites in Alloy 600 using 3D EBSD and Local Model: Naganand Saravanan1; Phani Karamched1; Theo Simonet2; Emilien Burger2; Thierry Couvant2; Sergio Lozano-Perez1; 1Department of Materials, University of Oxford; 2EDF
In this study, we present a detailed technique in obtaining the 3D EBSD data, reconstruction and converting it into mesh for modelling. The experiments were carried out on Alloy 600 sample by coupling the serial sectioning in Plasma FIB and electron backscatter detector (EBSD). The data is reconstructed using Dream3D software to obtain the actual 3D microstructure (with orientation). The 3D microstructure is then converted into finite element mesh for simulation using an optimized algorithm. The Crystal Plasticity Finite Element Modelling (CPFEM) is carried out on the mesh using Code Aster and Local model. The results presented show the crack initiation sites or the grain boundaries which are susceptible. This is then compared with the Alloy 600 sample exposed to SCC test in autoclave for 2000hrs with 30cc H2/kg H2O at 345°C. This novel approach opens the way to more systematic and quantitative analyses of microstructural effects on cracking.
4:15 PM
Mechanical Behavior of Thermoplastic Filaments Fabricated with the Fused Modeling Deposition Technique: Edisson Ordoņez1; Henry Colorado1; 1Universidad de Antioquia
Four different materials were evaluated after being fabricated via fused deposition modeling (FDM) technique. The materials used were Polylactic acid or polylactide (PLA), PLA with wood, PLA with carbon fiber, and Acrylonitrile butadiene styrene (ABS). The samples fabricated were specimens for the tensile test, which was conducted at 5mm/min at room temperature. Weilbull statistics was conducted for each sample composition, as well as scanning electron microscopy. Samples were printed at two different process temperatures. Defects and surface finishing were analyzed. Some parts printed and analyzed as potential impact energy absorbers are also presented in this research.