Environmental Degradation of Additively Manufactured Alloys: Environmental Degradation of Additively Manufactured Materials at High Temperatures and Radiation Environments
Sponsored by: TMS Structural Materials Division, TMS: Corrosion and Environmental Effects Committee
Program Organizers: Kinga Unocic, Oak Ridge National Laboratory; Jenifer Locke, Ohio State University; Sebastien Dryepondt, Oak Ridge National Laboratory; Brendy Rincon Troconis, University of Texas at San Antonio; Andrew Hoffman, Catalyst Science Solutions; Xiaoyuan Lou, Purdue University
Tuesday 8:00 AM
March 21, 2023
Room: Sapphire 400A
Location: Hilton
Session Chair: Kinga Unocic, Oak Ridge National Laboratory; Sebastien Dryepondt, ORNL
8:00 AM Invited
The Process-Structure-Performance Correlations of Additively Manufactured Steels Exposed to High Dose Neutron Irradiations: Kevin Field1; Pengyuan Xiu2; Niyanth Sridharan3; 1University of Michigan; 2University of Michigan; Now at: Intel Corporation; 3Lincoln Electric - India
Additive manufacturing (AM) including directed energy deposition (DED) methods are being considered for production of nuclear reactor components. Here, the process-structure-performance (p-s-p) paradigm will be discussed for nuclear grade steels produced via DED-based AM technologies and exposed to high dose (e.g., ≥50 displacements per atom – dpa) ion irradiations. Specifically, the role of impurity contributions due to the AM process on radiation-enhanced clustering, the influence of post-build heat treatments on the swelling response, and the influence of co-injected helium on the loop formation and swelling in DED produced HT9 is considered. The conditions studied includes damages up to 250 dpa at 445°C, and irradiation temperatures from 400°C to 480°C at 50 dpa. It will be shown that the p-s-p relationship in AM HT9 is highly sensitive to minor changes within the p-s-p factors, thus highlighting the additional complexities in considering high dose degradation phenomena in AM produced steels.
8:30 AM
Thermal response of Additive Manufactured Alloys Submitted to Transient High Heat Flux Testing: John Saputo1; Felipe Caliari1; Sanjay Sampath1; 1Stony Brook University
Additive manufacturing of special alloys has brought flexibility and efficiency by enabling novel design of components. Their complex structural and chemical composition, however, may result in phase segregation and anisotropic properties. Therefore, understand their behavior under high temperature environment is key to determine their durability in harsh environments. The degradation of materials has been investigated under controlled environmental conditions, while in real application they are submitted to gradient and transient thermal exposure. To address those limitations, a test method for extreme environments at highly transient thermal loading with heating rates on the order of 10,000 °C/min, heat fluxes on the megawatt scale, and a tunable continuously varying combustion environment is highlighted. The impact of this environmental degradation on alloys and coated alloy systems is explored in this context with the potential for coatings to extend the useful temperature range of both traditional and additively manufactured components demonstrated.
8:50 AM Cancelled
Enhanced High-temperature Oxidation of Additively Manufactured Ni-base Alloy IN625: Microstructure or Chemical Composition?: Anton Chyrkin1; Kerem Gunduz2; Irina Fedorova1; Wojciech Nowak3; Mohammad Sattari1; Mats Halvarsson1; Jan Froitzheim1; Krystyna Stiller1; 1Chalmers University of Technology; 2Chalmers University of Technology; Gebze Technical University; 3Rzeszow University of Technology
High-temperature oxidation behavior of additively manufactured (AM) Ni-base alloy IN625 has been studied in air and Ar-5%H2-3%H2O at 900-1000 °C. The alloy microstructure as well as the oxide scale morphologies were characterized with XRD, SEM, EDX, EBSD, TEM and GD-OES. The AM alloy variant has been shown to suffer from intergranular oxidation attack unlike its conventionally manufactured (CM) counterpart. Modifications of the AM microstructure such as grain-coarsening or hot-rolling did not alter the oxidation pattern, i.e., strong intergranular oxidation accompanied by void formation at alloy grain boundaries in the oxidation affected zone. Detailed analysis of minor differences in chemical composition of the AM and CM variants revealed the critical role of Si in oxidation protection of IN 625. Experiments with model alloys, as well as diffusion modeling, confirmed the crucial role of a minimum Si concentration to form a SiO2 subscale thereby preventing intergranular oxidation attack.
9:20 AM Break
9:40 AM
High-temperature Oxidation Behavior of Additively Manufactured Haynes 282 Samples in Direct-fired Supercritical CO2 Power Cycle Environments: Casey Carney1; Nicholas Lamprinakos2; Richard Oleksak3; Omer Doğan3; Anthony Rollett2; 1LRST; 2Carnegie Mellon University; 3National Energy Technology Laboratory
Materials selection is a key concern for corrosion resistance in elevated temperature and pressure direct-fired supercritical CO2 (sCO2) power cycles. Additive manufacturing (AM) is investigated to construct compact heat exchangers with complex geometry for these power cycles. Haynes 282 (H282) coupons manufactured using various laser powder bed fusion process parameters were exposed to direct-fired sCO2 conditions (95CO2 – 4H2O – 1 O2, 20 MPa) at both atmospheric pressure (T=850 °C) and supercritical pressure of 20 MPa (T=750 °C) for more than 2,000 hours. The oxidation behavior of AM H282 with both as-printed and ground surfaces will be contrasted with the behavior of wrought H282, so that the feasibility of the use of AM production methods of components for direct-fired sCO2 power cycles can be assessed.
10:00 AM
Impact of the Gas Composition on Oxide Scales formed on Ni-based Alloys in Metal Dusting Conditions: Clara Schlereth1; Martin Weiser2; Emma White1; Mathias Galetz1; 1DECHEMA-Forschungsinstitut; 2FAU Erlangen-Nürnberg
Steels and Ni-base alloys are aggressively attacked by metal dusting between 450 and 750°C in carbonaceous gas environments that are common to the energy and processing industries. Carbon from the gas first deposits, then diffuses inwards and finally disintegrates the material by internal graphite formation. Protection of the alloys from metal dusting can be achieved by Cr2O3 and/or Al2O3 scale formation. The oxide scale is formed in situ and its properties may thus depend on the amount of H2, CO, CO2, and H2O in the gas. The structure of oxide scales on alloy 601 formed in four gas mixtures with varying aggressivity is analyzed. SEM, XPS, and TEM are applied to characterize the morphology of the oxide scales, which are unevenly thick and contain metallic particles in the outer layer. This understanding is then applied to compare the metal dusting behavior of conventional and additively manufactured (AM) alloy 699XA.
10:20 AM
Metal Dusting and Surface Treatment of Additively Manufactured Ni-Cu Alloys and Alloy 699XA: Till Koenig1; Ceyhun Oskay1; Clara Schlereth1; Emma White1; Lukas Reiff2; Katrin Jahns2; Anke Silvia Ulrich1; Ulrich Krupp2; Mathias Galetz1; 1DECHEMA Research Institute; 2IEHK, RWTH Aachen
Ni-Cu alloys represent an interesting class of materials for carburizing conditions, since Cu inhibits the catalytic deposition of carbon and thereby increases the resistance to metal dusting. Since time and place of the metal dusting are difficult to predict, on-site additive manufacturing will help to keep plant downtimes low. In this study the metal dusting resistance of additively manufactured Ni-Cu alloys was investigated at 18 bar for up to 1000 h. The investigated alloys were binary and ternary Ni-Cu alloys as well as variations of Monel 400 in comparison to the additively manufactured alloy 699XA. The influence of the manufacturing process, alloy composition and surface treatment on metal dusting was investigated. As a new approach to surface refinement a pack cementation process was investigated for the alloy 699XA and tested in oxidizing conditions.