NSUF 16-611: In situ study of defect accumulation in Ti-6Al-4V under heavy ion irradiation
In previous studies, a dual dose and temperature dependence was observed in the mechanical properties of Ti-6Al-4V irradiated with neutrons[1], protons[3] and swift heavy ions[4]: Samples irradiated at higher temperature exhibited higher hardening at higher doses.The microstructure of irradiated Ti-6Al-4V was investigated by Tähtinen et al. 1 and Wilkes et al.[2] (irradiation with 17.5 MeV Cu4+ at 250°C, 350°C and 450°C at 1.5 dpa). At high temperature, the microstructure of irradiated Ti-6Al-4V is characterized by V-rich precipitates [1]or ß phase precipitation [2] at doses between 0.3 and 1.5 dpa. However, at low temperature, TEM investigations showed mainly a high density of dislocation loops [1]. The microstructure evolution induced different obstacles to the dislocation motion and could explain this higher hardening at high temperature and doses. In these studies, only the final irradiated microstructure at a certain damage level was investigated which leaves gaps in our understanding of the damage mechanisms. In-situ TEM irradiation offers the unique capability to investigate the evolution of the irradiation damage through continual imaging and observation. It allows for quantitative and qualitative microstructural studies. Similar studies were able to image the dislocation movement and the grain boundary effect in an exceptional accuracy in zirconium and its alloys [5][6][7]. Using IVEM-Tandem Facility at Argonne National Laboratory with its in-situ TEM irradiation capability could improve the understanding of the irradiation damage in Ti-6Al-4V and explain the results obtained from tensile testing. We are proposing to irradiate 6 TEM samples (3 mm disks) with 1 MeV Kr2+ ions to different damage levels ranging from 0.008 dpa to 1 dpa [7] and at different temperatures 25°C, 100°C (intermediate temperature) and 350 °C. The range of Kr ions in a Ti-6Al-4V target estimated with SRIM-2013 is ~ 450 nm. The thickness of the TEM foils (~100 nm) would allow for a homogeneous irradiation of the whole thickness. The TEM samples will be characterized before irradiation at Michigan State University. The sample preparation costs would be covered by MSU. The machine time was estimated based on SRIM calculations for a damage rate of ~ 9x10e-3 dpa.s-1. The needed machine time is 2 daysi, including set up time and sample handling.
Additional Info
| Field | Value |
|---|---|
| Abstract | In previous studies, a dual dose and temperature dependence was observed in the mechanical properties of Ti-6Al-4V irradiated with neutrons[1], protons[3] and swift heavy ions[4]: Samples irradiated at higher temperature exhibited higher hardening at higher doses.The microstructure of irradiated Ti-6Al-4V was investigated by Tähtinen et al. [1](Neutron irradiation at 350°C and at 0.3 dpa) and Wilkes et al.[2] (irradiation with 17.5 MeV Cu4+ at 250°C, 350°C and 450°C at 1.5 dpa). At high temperature, the microstructure of irradiated Ti-6Al-4V is characterized by V-rich precipitates [1]or ß phase precipitation [2] at doses between 0.3 and 1.5 dpa. However, at low temperature, TEM investigations showed mainly a high density of dislocation loops [1]. The microstructure evolution induced different obstacles to the dislocation motion and could explain this higher hardening at high temperature and doses. In these studies, only the final irradiated microstructure at a certain damage level was investigated which leaves gaps in our understanding of the damage mechanisms. In-situ TEM irradiation offers the unique capability to investigate the evolution of the irradiation damage through continual imaging and observation. It allows for quantitative and qualitative microstructural studies. Similar studies were able to image the dislocation movement and the grain boundary effect in an exceptional accuracy in zirconium and its alloys [5][6][7]. Using IVEM-Tandem Facility at Argonne National Laboratory with its in-situ TEM irradiation capability could improve the understanding of the irradiation damage in Ti-6Al-4V and explain the results obtained from tensile testing. We are proposing to irradiate 6 TEM samples (3 mm disks) with 1 MeV Kr2+ ions to different damage levels ranging from 0.008 dpa to 1 dpa [7] and at different temperatures 25°C, 100°C (intermediate temperature) and 350 °C. The range of Kr ions in a Ti-6Al-4V target estimated with SRIM-2013 is ~ 450 nm. The thickness of the TEM foils (~100 nm) would allow for a homogeneous irradiation of the whole thickness. The TEM samples will be characterized before irradiation at Michigan State University. The sample preparation costs would be covered by MSU. The machine time was estimated based on SRIM calculations for a damage rate of ~ 9x10e-3 dpa.s-1. The needed machine time is 2 daysi, including set up time and sample handling. |
| Award Announced Date | 2015-12-16T00:00:00 |
| Awarded Institution | Idaho National Laboratory |
| Facility | ATR Critical Facility |
| Facility Tech Lead | Alina Zackrone, Wei-Ying Chen |
| Irradiation Facility | None |
| PI | Carl Boehlert |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 611 |