Effect of elastic stresses on solid-state amorphization of Zr/Co multilayers

We have examined the effect of externally applied stresses on the solid-state amorphization reaction of Zr/Co multilayers prepared by electron-beam evaporation. Three identically deposited samples were attached onto a three-point bending apparatus to impose different elastic strains on individual samples and subsequently annealed at temperatures of 483, 503 and 543 K. The imposed bending strain, estimated to be as small as 0.08%, had a significant influence on the amorphization kinetics. Cross-sectional transmission electron microscopy revealed clearly that changing the applied bending strain from tensile to compressive enhanced the amorphization reaction. This enhancement was accompanied by an extensive amorphization along grain boundaries in the Zr layers. According to the present observations, it is suggested that the applied bending stresses play an important role in the amorphization reaction by influencing the interface reaction barrier associated with the actual transformation of the terminal solution phase of Zr into the amorphous phase.