| Description |
viii, 90 leaves : illustrations, photographs ; 29 cm |
| Summary |
"Resistivity measurements were made on ordered and disordered Fe₃Al samples while irradiated by neutrons. In the ordered as well as the disorder state, the different Fe₃Al samples were heated to 100, 150, 200, 250, and 300°C respectively, and were irradiated by a fast neutron flux of 0.534 x 10¹⁰ neutrons/cm²-sec. The ordered Fe₃Al measurements were characterized by an increase in resistivity denoting an advancement toward disorder. The disordered Fe₃Al measurements were characterized by a decrease in resistivity denoting an advancement toward order. In the Fe₃Al ordered and disordered samples irradiated at 300°C, the resistivities tended to become constant as the fast neutron flux reached 19.2 x 10¹³ neutrons/cm². This indicated that the amount of disordering is in equilibrium with the amount of ordering, and that the relatively high temperature of 300°C is the cause for this. The other ordered and disordered Fe₃Al samples irradiated at lower temperatures did not show this effect when the fast neutron flux reached 19.2 x 10¹³ neutrons/cm². If these samples had continued to be neutron irradiated, they too, at some higher flux, would have experienced this effect of the amount of disordering approximately equaling the ordering. Two different long range order parameters were obtained for both the ordered and disordered Fe₃Al samples. Resistivity measurements were used to calculate one of the parameters. In this case, the resistivity at the elevated temperature was used. The second long range order parameter was obtained by integrated intensities of the x-ray diffraction pattern. In this case, the order parameter was obtained for room temperature. It was found that the parameter obtained by the integrated intensity method, for both ordered and disordered samples, was substantially larger than the one obtained by using the resistivity method. This indicated that the point defects produced during irradiation were annealed as the Fe₃Al samples were cooled from the test temperature to room temperature"--Abstract, leaves ii-iii. |
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