NSUF 24-4964: Irradiation Damage Rate Effect on the Dislocation Cell Structure of Additively Manufactured 316L
Additive manufacturing (AM) can fabricate complex geometries rapidly and cost effectively, leading to increasing attention recently as a new way of making high-quality components for nuclear reactors. There are several microstructural differences between wrought 316 SS and AM 316, such as dislocation cell structures, Si-Mn oxides, chemical segregation, porosity, and others. While AM materials are compositionally similar to their conventionally produced counterparts, they do possess different microstructures, such as a sub-grain like structure known as “dislocation cells”, porosity and chemical inhomogeneity, which can lead to different mechanical properties and performance. These microstructures and their behavior under service conditions must be evaluated carefully before AM materials can be deployed. Previous studies have shown that the distribution of dislocation loops and voids are affected by dislocation cell structures making their evolution critical to the co-evolution of the microstructure under irradiation. The objective of this study is to examine how dislocation cell walls evolve under irradiation at multiple damage rates to separate the contributions of thermal diffusion and irradiation enhanced diffusion. Our hypothesis is that the thermal relaxation contributes more to dislocation cell wall dissolution under neutron irradiation (10-6 dpa/s) than with ion irradiation (10-3 dpa/s) because of the difference in time for defects to diffuse. Our approach is performing a series of single ion irradiations across an order of magnitude in damage rate, and therefore time, to the same level of displacement damage to deconvolute thermal and radiation processes. The proposing team seeks use, through the Nuclear Science User Facilities, of the Michigan Ion Beam Laboratory for three ion irradiations and the Michigan Center for Materials Characterization (MC2) for TEM lamella preparation and characterization of dislocation loops, dislocation cells, and possibly cavities. We propose to perform three single ion irradiation experiments and associated PIE. We will perform single ion irradiations at 600°C using 9 MeV Ni3+ ions to fluences of 5.0 × 1015 ions/cm2 with fluxes of 2.6 × 10^11 ions/cm2-s, 1.3 × 10^11 ions/cm2-s, or 2.6 × 10^10 ions/cm2-s to produce about 2 displacements per atom at nominal damage rates of 10^-4, 5×10^-5, and 10^-5 dpa/s. The proposed experiments will require an estimation of about 78 hours for three single ion irradiations and 48 hours for post-irradiation examination. The successful result of PIE of 316 SS will show the dissolution of dislocation cell structure as a function of damage rate, which will help (1) understand the influence of dislocation cell structure affecting damage accumulation under different irradiation conditions (2) develop cluster dynamic models that systematically utilize neutron and ion data for predicting AM 316 SS performance in nuclear reactors. The outcome will accelerate the qualification of AM316 SS for nuclear applications and will offer industry a rapid and cost-effective alternative for building advanced reactor components.
추가 정보
| 필드 | 값 |
|---|---|
| Award Announced Date | 2024-05-28T17:08:22.14 |
| Awarded Institution | Argonne National Laboratory |
| Facility Tech Lead | Kevin Field |
| Irradiation Facility | |
| PI | Wei-Ying Chen |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | None |