Structural relaxation on Fe44Ni38B18 amorphous alloy by Young's modulus measurements

When rapid quenching occurs, avoiding crystallization, the undercooled liquid becomes an amorphous solid whose structure is metastable not only with respect to crystalline state, but also with respect to a theoretical deal glass. It is possible, then, that this structure can evolve towards a more amorphous stable state. This evolution is called structural relaxation and it causes important changes in physical, chemical and mechanical properties. The study of structural relaxation is a very important matter because, in many cases, the optimum properties of amorphous materials are obtained after an adequate heat treatment. This paper reports that, up to now different properties have been used for structural relaxation studies: dilatation, Young's modulus, enthalphy, lifetime of positron annihilation, microhardness, electrical resistivity, and Curie temperature. The Young's modulus is a very suitable parameter to analyze the relaxation in metallic glasses because the changes caused by these processes, in the mentioned parameter, are relatively large -for example, about an order greater than those obtained in dilatometric measurements