NSUF 18-1207: Irradiation-induced precipitation/segregation in dual-phase Al0.3CoCrFeNi alloy
The objective of this proposal is to study irradiation-induced precipitation/segregation in a dual-phase multi-component alloy-Al0.3CoCrFeNi at elevated temperatures, including the precipitation in both phases (fcc and B2) and the segregations at grain boundaries. Multi-component concentrated alloys are newly emerging advanced materials, which are defined as a multi-element alloy composed of four or more principal elements in equimolar or near-equimolar ratios. Irradiation responses of multi-component concentrated alloys with single phase have been widely studied. It is found that irradiation-induced damage accumulation is suppressed with increasing principal elements, suggesting the great advantage of multi-component concentrated alloys using as nuclear materials. Furthermore, irradiation-induced volume swelling can be decreased by controlling the number and the type of alloying elements. However, most of studies are focused on the single-phase system in order to obtain a deep understanding of the effects of compositional complexity on the defect behavior. The irradiation responses of multi-component systems with multi-phase, especially dual-phase systems which have better mechanical properties at both room temperature and high temperature, remain unexplored. Here, we study a dual-phase multi-component alloy-Al0.3CoCrFeNi with composition Al-3.47 wt.%; Co-25.23 wt.%; Cr-22.26 wt.%; Fe-23.91 wt.%; Ni-25.13 wt.%. After annealing at 700 oC for 500 h, a high density of precipitates with B2 structure and enriched with Ni, Al is found, and these highly dispersed, coherent precipitates strengthen the alloy with acceptable ductility (room temperature strength ~700 MPa and moderate ductility ~30% total). Ion irradiation experiments will be performed using 5 MeV Ni at 250 °C, 350 °C, 500 °C and 650 °C in our home institution to a fluence of 2×1016 cm-2. Irradiation-induced defects and the precipitation behavior in the matrix will be first characterized by TEM. Nano indentation will be used to measure the hardness and modulus after ion irradiation. Since irradiation can result in the variations of composition, such as precipitation, mixing, segregation at defects and grain boundaries, the evolution of chemical composition under high temperature ion irradiation is crucial for evaluating its irradiation resistance. Therefore, Atom Probe Tomography (APT) characterizations are proposed to be performed in the Microscopy and Characterization Suite (MaCS) at the Center for Advanced Energy Studies (CAES) to study the evolutions of chemical compositions in both phases and at grain boundaries. Furthermore, since APT is a very sensitive characterization approach, we can obtain the quantitative precipitation/solute precipitation behavior and segregation at grain boundaries. Based on the various characterization results, we want to obtain a comprehensive understanding of the chemical composition evolution of dual-phase multi-component alloy Al0.3CoCrFeNi under high temperature ion irradiations and to verify the possible application of the dual-phase multi-component alloy in advanced nuclear reactors (Generation IV).
Additional Info
| Field | Value |
|---|---|
| Abstract | The objective of this proposal is to study irradiation-induced precipitation/segregation in a dual-phase multi-component alloy-Al0.3CoCrFeNi at elevated temperatures, including the precipitation in both phases (fcc and B2) and the segregations at grain boundaries. Multi-component concentrated alloys are newly emerging advanced materials, which are defined as a multi-element alloy composed of four or more principal elements in equimolar or near-equimolar ratios. Irradiation responses of multi-component concentrated alloys with single phase have been widely studied. It is found that irradiation-induced damage accumulation is suppressed with increasing principal elements, suggesting the great advantage of multi-component concentrated alloys using as nuclear materials. Furthermore, irradiation-induced volume swelling can be decreased by controlling the number and the type of alloying elements. However, most of studies are focused on the single-phase system in order to obtain a deep understanding of the effects of compositional complexity on the defect behavior. The irradiation responses of multi-component systems with multi-phase, especially dual-phase systems which have better mechanical properties at both room temperature and high temperature, remain unexplored. Here, we study a dual-phase multi-component alloy-Al0.3CoCrFeNi with composition Al-3.47 wt.%; Co-25.23 wt.%; Cr-22.26 wt.%; Fe-23.91 wt.%; Ni-25.13 wt.%. After annealing at 700 oC for 500 h, a high density of precipitates with B2 structure and enriched with Ni, Al is found, and these highly dispersed, coherent precipitates strengthen the alloy with acceptable ductility (room temperature strength ~700 MPa and moderate ductility ~30% total). Ion irradiation experiments will be performed using 5 MeV Ni at 250 °C, 350 °C, 500 °C and 650 °C in our home institution to a fluence of 2×1016 cm-2. Irradiation-induced defects and the precipitation behavior in the matrix will be first characterized by TEM. Nano indentation will be used to measure the hardness and modulus after ion irradiation. Since irradiation can result in the variations of composition, such as precipitation, mixing, segregation at defects and grain boundaries, the evolution of chemical composition under high temperature ion irradiation is crucial for evaluating its irradiation resistance. Therefore, Atom Probe Tomography (APT) characterizations are proposed to be performed in the Microscopy and Characterization Suite (MaCS) at the Center for Advanced Energy Studies (CAES) to study the evolutions of chemical compositions in both phases and at grain boundaries. Furthermore, since APT is a very sensitive characterization approach, we can obtain the quantitative precipitation/solute precipitation behavior and segregation at grain boundaries. Based on the various characterization results, we want to obtain a comprehensive understanding of the chemical composition evolution of dual-phase multi-component alloy Al0.3CoCrFeNi under high temperature ion irradiations and to verify the possible application of the dual-phase multi-component alloy in advanced nuclear reactors (Generation IV). |
| Award Announced Date | 2018-02-01T14:15:14.293 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Yaqiao Wu |
| Irradiation Facility | None |
| PI | Steven Zinkle |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 1207 |