A thermodynamic model for solid state amorphization: application to Ni-Ti multilayers of different microstructures

摘要

On the basis of an assessment of both the phase-formation energies and the energies of interfaces and grain boundaries the driving force for solid state amorphization (SSA) in crystalline Ni- crystalline Ti and amorphous Ni- crystalline Ti multilayers was calculated. It followed that the structure of the interfaces and grain boundaries, and thus their energies is of crucial importance for the occurrence (or not) of SSA. The SSA behaviour of the two types of Ni-Ti multilayes upon annealing was investigated using X-ray diffraction and (high resolution) transmission electron microscopy. The crystalline Ni- crystalline Ti multilayers showed SSA at both the Ni-Ti interfaces and the Ti grain boundaries. The amorphous Ni- crystalline Ti multilayers exhibited SSA at the Ti grain boundaries only. These observations agree with the predictions from the thermodynamic model.