NSUF 24-4817: Investigating the evolution of M23C6 and MX-type precipitates in additively manufactured Grade 91 steel under high temperature simultaneous and sequential stress and irradiation
We propose conducting tests on an additively manufactured (AM) Grade 91 steel with homogeneous distribution of secondary phases, including creep, creep post-irradiation (sequential), and simultaneous irradiation with creep loading. We hypothesize that the evolution of carbides and MX carbonitride precipitates, and thus creep and radiation resistance, in Grade 91 steel is strongly impacted by the pathway for creep evaluation. This is due to differences in anisotropic diffusion and precipitate coarsening between sequential testing and simultaneous testing. The outcome of this work will be, to the proposers' knowledge, the first ion irradiation creep test evaluations of AM Grade 91 steel with systematic testing techniques and correlative microstructural evaluation.
We will perform simultaneous and sequential irradiation-creep effects tests on AM Grade 91 steel. Samples will be fabricated via laser powder bed fusion. Post-processing will involve normalizing, tempering, and machining to produce uniform microstructure and required test coupon geometry. Tapered specimens will undergo 3 MeV proton irradiation to induce radiation damage without significant hydrogen effects. During testing, temperature and strain measurements will be captured to generate stress-strain data. The experimental matrix will include 3 thermal creep tests – thermal creep at 550 °C and a stress range of 162-316 MPa on unirradiated sample; irradiation without load to a dose of 0.4 dpa at 550 °C followed by thermal creep testing at 550 °C and a stress range of 162-316 MPa; and simultaneous irradiation + creep under the same conditions. In total, tests will span 4 weeks at the user facility. The resulting dataset will reveal impacts of irradiation on creep behavior and microstructural evolution. By correlating stress-strain response with post-irradiation examination, fundamental understanding of creep in irradiated Grade 91 will be gained. This work will provide the first systematic ion irradiation creep evaluation of additively manufactured Grade 91 steel.
추가 정보
| 필드 | 값 |
|---|---|
| Award Announced Date | 2024-02-02T12:12:33.377 |
| Awarded Institution | Carnegie Mellon University |
| Facility Tech Lead | Kevin Field |
| Irradiation Facility | Michigan Ion Beam Laboratory |
| PI | Sneha Prabha Narra |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | None |