TY - JOUR
T1 - Unusual irradiation-induced disordering in Cu3Au near the critical temperature
T2 - An in situ study using electron diffraction
AU - Lear, Calvin Robert
AU - Averback, Robert S.
AU - Bellon, Pascal
AU - Sand, Andrea Elisabet
AU - Kirk, Marquis A.
PY - 2018/11/28
Y1 - 2018/11/28
N2 - Atomic mixing by replacement collision sequences and other cascade effects is well known to create chemical disorder in irradiated alloys. Most studies of irradiation-induced disordering have focused on ex situ analysis of irradiated samples; however, fast in situ techniques are necessary to measure disordering at elevated temperatures without significant interference from concurrent re-ordering processes. In the present work, we use in situ electron diffraction with high speed data collection to measure the initial change in the long-range order parameter S with ion dose phi during 500 keV Ne+ irradiation of Cu3Au foils. The data reveal an unexpected and dramatic increase in the disordering rate as the critical order-disorder transition temperature T-C is approached. Molecular dynamics simulations show that this increase is not due to temperature-dependent cascade mixing. We attribute the enhanced disordering, instead, to coupling between point defect fluxes and the chemical state of order.
AB - Atomic mixing by replacement collision sequences and other cascade effects is well known to create chemical disorder in irradiated alloys. Most studies of irradiation-induced disordering have focused on ex situ analysis of irradiated samples; however, fast in situ techniques are necessary to measure disordering at elevated temperatures without significant interference from concurrent re-ordering processes. In the present work, we use in situ electron diffraction with high speed data collection to measure the initial change in the long-range order parameter S with ion dose phi during 500 keV Ne+ irradiation of Cu3Au foils. The data reveal an unexpected and dramatic increase in the disordering rate as the critical order-disorder transition temperature T-C is approached. Molecular dynamics simulations show that this increase is not due to temperature-dependent cascade mixing. We attribute the enhanced disordering, instead, to coupling between point defect fluxes and the chemical state of order.
UR - https://researchportal.helsinki.fi/en/publications/3b0a2d01-16e5-457c-a579-719e38410b89
U2 - 10.1557/jmr.2018.308
DO - 10.1557/jmr.2018.308
M3 - Article
JO - Journal of Materials Research
JF - Journal of Materials Research
SN - 0884-2914
ER -