Radiometric and autoradiographic study on the impurity distribution factor in molybdenum when electron beam zone melting

Impurity distribution factor was studied in molybdenum when electron beam zone melting using 192Ir radioisotope. 192Ir concentration profile along a zone-melted ingot was analyzed by the radiometric method. The radiometric method was further used for direct determination of the 192Ir effective distribution factor in molybdenum by the comparison between the impurity concentration in the suddenly solidified zone and that in the molten.metal in front of this zone. Longitudinal and cross-sectional impurity distribution in the zone-melted crystal was studied by autoradiography. A zone of 192Ir increased concentration was observed. Its arising can be attributed to the turbulence of melt resulted in crystallization rate fluctuation