AN INSITU TEM OBSERVATION ON THE THERMAL-STABILITY OF A NANOCRYSTALLINE FEBSI ALLOY

The thermal stability of nanocrystalline Fe78B13Si9, prepared by cryst allization, has been studied by in situ heating TEM observations at te mperatures from 450 to 650-degrees-C. The nanocrystalline FeBSi alloy, with an average grain size of about 30 nm, was found to be thermally stable with nondetectable grain growth up to temperature of 450-degree s-C. The grain growth results can be discussed in terms of the mechani sms of precipitation, solute, vacancies and grain boundary triple junc tions which may be operative in reducing the overall mobility of the i nterfaces. At the elevated temperature of about 650-degrees-C, seconda ry recrystallization occurred with abnormal growth of a few grains.