Tracer Diffusion of Molybdenum in Crystallized Fe_(79-y)Mo_8Cu_1B_(12+y) Alloy

摘要

Mo tracer diffusion in Fe79.J,Mo8CuIBa+;, (y = 0, 3, 5) alloys was studied using serial sectioning method in the temperature range 573 - 773 K. Sputtering by Ar+ ions was applied as a sectioning technique. The measurement was carried out with the ribbon-like samples prepared by planar flow casting technique and crystallized before the diffusion experiment by a thermal shock in vacuum. The structure was formed by areas of three distinct types differing in chemical composition r = at. % Mo / at. % Fe: (iii) r = 0.02 (crystallites of Fe, mean size d ～ 150 nm), (ii) r = 0.09 (relaxed phase; d ～ 150 nm) and (Hi) r = 0.83 (boride phase; d ～ 30 nm). The measured profiles were linear in co-ordinates In cUo vs. x15 (CM0 - concentration of Mo in depth x), indicating that the diffusion of 99Mo was controlled by ,,type A-B" kinetics.