REVERSIBLE STRUCTURAL RELAXATION IN FE-B-SI AMORPHOUS-ALLOYS

Reversible structural relaxation in two Fe-B-Si amorphous alloys, Fe78 B7Si15 and Fe75B10Si15, has been studied through measurements of the e lectrical resistance and relaxation enthalpy using a differential scan ning calorimeter. Both alloys exhibited reversible changes of these ph ysical properties due to the reversible relaxation. Larger reversible changes were observed in Fe78B7Si15 than in Fe75B10Si15. This result c an be well explained by the idea that the reversible relaxation is cau sed by changes in chemical short-range order among iron and silicon at oms according to Dubois and Le Caer's structural model of amorphous al loys. The activation energy spectrum characterizing the reversible rel axation process was obtained from reversible enthalpy changes during i sothermal annealing at 500 K. It results in an asymmetric gaussian-lik e distribution with a peak maximum at 1.7 eV.