NSUF 24-5182: Mechanical and microstructural characterization of neutron irradiated ultra-fine-grained and conventional ferritic steel
The major objective of the proposed work is to characterize the effect of neutron irradiation on microstructure and mechanical properties of ultrafine grained (UFG) ECAP steel and compare it with the corresponding characteristics of conventional grain sized (CG) steel. UFG ferrtic steel (grain size 0.35 micron) was made by ECAP (equal channel angular pressing) using Bc route with four passes where the material was rotated 90 in the same direction after each pass. Conventional coarse grain (grain size 4.4 micron) counterpart was produced by annealing the UFG material at 800C for one hour. As a part of an NSUF Irradiation Experiment FY08 project funded at NCSU (one of the first NSUF projects; led by the same PI), CG and UFG ferritic steel samples were irradiated in ATR (~1.3 and 2.6 dpa; 80-89C). Partial work was completed on ~1.3 dpa samples under an NSUF RTE award #14-482. Mechanical properties of ~1.3 dpa irradiated samples were characterized using microhardness and tensile tests, and irradiation of UFG steel revealed minor radiation effects in contrast to the distinct radiation hardening and reduction of ductility in its CG counterpart. After irradiation, microhardness increased by~ 9% for UFG versus 62% for CG steel. Similarly, tensile strength increased by ~8% and 94% respectively for UFG and CG steels while corresponding reduction in ductility were 56% versus 82%. Maximum impact of this work will be obtained by performing TEM microstructural characterization of these irradiated samples to correlate the measured hardening with microstructural features. Extrapolation of the information learned from the ~1.3 dpa irradiation is best accomplished by also examining the mechanical properties and microstructure of the ~2.6 dpa samples because having data at two doses results in a more accurate extrapolation to higher doses. Hence, we propose to perform a comprehensive mechanical (~2.6 dpa samples; tensile and microhardness) and microstructural characterization (~1.3 and 2.6 dpa samples; TEM) of CG and UFG steels to understand the effect of grain size on the irradiation resistance of the material and quantify the irradiation-induced defects present in these materials. The proposed study thus meets the mission of DOE office of nuclear energy in the development of relatively more radiation resistant materials especially for the next generation nuclear reactors with design goals of more severe service conditions along with longer life cycles. The project performance is expected to take place during Oct’24-Apr’25 and will result in one conference presentation and one journal article publication.
추가 정보
| 필드 | 값 |
|---|---|
| Award Announced Date | 2024-09-23T12:22:29.343 |
| Awarded Institution | North Carolina State University |
| Facility Tech Lead | Alina Montrose, Stuart Maloy |
| Irradiation Facility | |
| PI | Korukonda Murty |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | None |