Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 42 Page 43 Page 44 Page 45 Page 46 Page 47 Page 48 Page 49 Page 50 Page 51 Page 52 Page 53 Page 54 Page 55 Page 56 Page 57 Page 58 Page 59 Page 60 Page 61 Page 62 Page 63 Page 64 Page 65 Page 66 Page 67 Page 68 Page 69 Page 70 Page 71 Page 72 Page 73 Page 74 Page 75 Page 76 Page 77 Page 78 Page 79 Page 80 Page 81 Page 82 Page 83 Page 84 Page 85 Page 86 Page 87 Page 88 Page 89 Page 90 Page 91 Page 92 Page 93 Page 94 Page 95 Page 96 Page 97 Page 98 Page 99 Page 100 Page 101 Page 102 Page 103 Page 104 Page 105 Page 106 Page 107 Page 108 Page 109 Page 110 Page 111 Page 112 Page 113 Page 114 Page 115 Page 116 Page 117 Page 118 Page 119 Page 120 Page 121 Page 122 Page 123 Page 124Nuclear Science User Facilities 104 Investigation of Precipitate Formation Kinetics and Interactions in FeCrAl Alloys Samuel A. Briggs – University of Wisconsin, Madison – sabriggs2@wisc.edu Figure 1. α’ precipitates represented by 34 at.% Cr concentration isosurfaces for (a) Fe‑10Cr‑4.8Al, (b) Fe‑12Cr‑4.4Al, (c) Fe‑15Cr‑3.9Al, and (d) Fe‑18Cr‑2.9Al, neutron- irradiated in HFIR to 7dpa at 320°C. Black dots represent 2% of detected matrix Fe atoms. FeCrAl alloys are currently being considered for accident-tolerant light water reactor (LWR) fuel cladding applications and show promise as a new alloy class for nuclear systems due to their superior oxida- tion and corrosion resistance in high temperature environments. However, high‑Cr (>9 at.%) ferritic alloys are known to be susceptible to precipita- tion of a deleterious α’ phase during long-term high-temperature exposure. This process has been shown to be accelerated by irradiation and tends to result in hardening and embrittlement of the material.As such, it is important to understand the factors that influence the formation of these precipitates to mitigate their effect on material properties when designing an alloy for nuclear applications. Project Description This work investigates the composition and dose dependencies for α’ precipita- tion in neutron‑irradiated FeCrAl alloys using atom probe tomography (APT) techniques as part of a rigorous irra- diation and characterization campaign under the DOE Fuel Cycle Research and Development (FCRD) program.The data collected from theAPT technique is reconstructed into a three-dimensional (3-D) rendering of the material in question and allows for detailed study of the spatial distribution of constituent elements, allowing for identification and study of the morphology and distribu- tion of Cr‑rich α’ clusters in the α‑Fe matrix with relative ease. Of particular interest are the shape, size, number density and composition of the precipi-