NSUF 18-1412: Irradiated Microstructure Evolution in Cast Compared to PM-HIP Alloy 625
The objective of this study is to determine the influence of processing method – casting or powder metallurgy with hot isostatic pressing (PM-HIP) on the irradiated microstructure evolution in Alloy 625. Recently, PM-HIP alloys have been developed and introduced for pressure-retaining applications in the electric power industry. PM-HIP alloys exhibit excellent structural uniformity, no chemical segregation during processing, superior mechanical properties, and enhanced weldability as compared to conventional cast or forged alloys. In addition, PM-HIP components are produced near-net shape, which offers distinct advantages of minimizing the need for machining and enhancing the ease of component inspectability. Because of these exceptional properties and features, PM-HIP alloys are of interest to the nuclear power industry as potential structural materials for light water reactors (LWRs), advanced LWRs (ALWRs), small modular reactors (SMRs), and advanced (e.g. Generation IV) reactors. NSUF is supporting neutron irradiation qualification of PM-HIP alloys through the ongoing project “Irradiation Influence on Alloys Fabricated by Powder Metallurgy and Hot Isostatic Pressing for Nuclear Applications”. In advance of the neutron irradiated samples being available for post-irradiation examination (PIE), NSUF has also supported accelerated ion irradiations of PM-HIP alloys as a scoping study to enable a more informed and strategic PIE effort of the high-value neutron irradiated specimens once they become available. Now, this proposal seeks to conduct the necessary PIE of these ion irradiated PM-HIP alloys, leveraging previous NSUF investments.
In this project, we will compare the irradiated microstructure in PM-HIP Inconel alloy 625, to that of the cast (i.e. conventionally fabricated) counterpart. Although Ni-base alloys, including IN625, are not known for irradiation tolerance, their high temperature corrosion resistance has made them candidates for in-core components of Generation IV plants and SMRs, where they will receive high irradiation doses. As such, their microstructural response to irradiation must be understood, and has accordingly been noted as a high-priority knowledge gap in a 2012 Electric Power Research Institute report, justifying the purpose of the work proposed herein. Thus far, we have conducted a scanning electron microscopic (SEM) investigation of the cast and PM-HIP IN625; electron backscatter diffraction (EBSD) grain orientation mapping has revealed a refined grain size and more twinning in the PM-HIP version. Because of the finer grain structure in PM-HIP IN625, which serves as a strong point defect sink, we hypothesize that: (1) the PM-HIP alloy will be more resistant to void and dislocation loop nucleation than the cast alloy, but that (2) the PM-HIP alloy will exhibit more radiation-induced segregation (RIS). Our design of experiments enables a thorough investigation of this hypothesis, by characterizing microstructure evolution in PM-HIP and cast IN625 following 5 MeV Ni+ ion irradiation at 450°C to 50, 100, and 200 displacements per atom (dpa). Transmission electron microscopy (TEM) will allow us to ascertain the relationship between grain boundary sink strength, RIS, and void and loop nucleation. More broadly, we will gain some of the first insight into the effect of processing method on irradiated microstructure evolution, enabling more scientifically informed studies of forthcoming neutron irradiated PM-HIP materials.
Допълнителна информация
| Поле | Стойност |
|---|---|
| Awarded Institution | None |
| Embargo End Date | 2020-02-17 |
| Facility Tech Lead | Alina Montrose, Catou Cmar |
| NSUF Call | FY 2018 RTE 2nd Call |
| PI | Janelle Wharry |
| Project Member | Bradley Fromm - Washington State University |
| Project Member | Professor Janelle Wharry, Professor - University of Illinois (https://orcid.org/0000-0001-7791-4394) |
| Project Notes | Awarded on 05/17/2018 |
| Project Type | RTE |
| Publication | Grain Evolution in Thermally Aged Cast and Hot Isostatic Pressed Inconel 625 Elizabeth Getto, Janelle Wharry Microscopy and Microanalysis Suppl 1 2018-08-01 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/91FF4853CC4982EFF9BE397C847B880F/S1431927618003823a.pdf/grain_evolution_in_thermally_aged_cast_and_hot_isostatic_pressed_inconel_625.pdf |
| Publication | Effect of residual stress mitigation surface treatment techniques on the irradiation tolerance of Ni-base alloys Keyou Mao, Vijay Vasudevan, Janelle Wharry FONTEVRAUD 9 2018-09-17 - 2018-09-20 |
| Publication | Grain evolution in thermally aged cast and hot isostatic pressed Inconel 625 Elizabeth Getto, Janelle Wharry Poster - M&M 2018 2018-08-05 - 2018-08-09 |
| Publication | Method for extracting true stress from TEM in situ compression testing Kayla Yano, Janelle Wharry M&M 2018 2018-08-05 - 2018-08-09 |
| Publication | Assessing mechanical properties of irradiated materials by nanomechanical testing Janelle Wharry, Kayla Yano, Yaqiao Wu ICSMA18 2018-07-15 - 2018-07-18 |
| Publication | TEM in situ mechanical testing of proton irradiated nanocrystalline copper tantalum alloy Yaqiao Wu, Janelle Wharry TMS 2018 2018-03-11 - 2018-03-15 |
| Publication | Microstructural and mechanical integrity of laser weldment of neutron irradiated AISI 304 SS Keyou Mao, Paula Freyer, Frank Garner, Janelle Wharry TMS 2018 2018-03-11 - 2018-03-15 |
| Publication | Mechanics of irradiated alloys studied through in situ TEM testing Janelle Wharry, Kayla Yano, Yaqiao Wu TMS 2018 2018-03-11 - 2018-03-15 |
| Publication | Temperature shift for emulating solute cluster evolution using higher dose rate irradiation Matthew Swenson, Janelle Wharry TMS 2018 2018-03-11 - 2018-03-15 |
| Publication | Comparison of ion irradiation effects in PM-HIP and forged alloy 625 Caleb Clement, Yangyang Zhao, Xiang Liu, David Gandy, Janelle Wharry Journal of Nuclear Materials 558 2022-01-12 https://www.sciencedirect.com/science/article/pii/S0022311521006103#ack0001 |
| Publication | Comparison of ion irradiation effects in PM-HIP and forged alloy 625 Caleb Clement, Patrick Warren, Yangyang Zhao, Xiang Liu, David Gandy, Janelle Wharry Journal of Nuclear Materials 558 https://doi.org/10.1016/j.jnucmat.2021.153390 |
| RTE Number | 1412 |