Papers by Keyword: Structural Inhomogeneity

Abstract: The relation between the annealing temperature dependence of the structural inhomogeneity and the diffusion coefficient in a metallic glass forming system Zr-Ti-Cu-Ni-Be is studied by using reported experimental data. It is shown that the diffusion coefficient increases with the increase of the correlation length of the structural inhomogeneity. Interestingly, the result found resembles the behavior known in superionic glasses. A discussion on the found relationship is given by exploiting the model for the superionic glasses proposed by the author. Based on the model, an inhomogeneity dependent diffusivity maximum is predicted.

Abstract: Numerical methods used to calculate strength are based on energy approaches and minimization of functionals of one type or another. Yet the model of a material is limited to stable processes of deformation. As a result, a considerable number of deformation properties related to realization of the softening stage in materials of structural elements remains unaccounted for. To describe fracture as a new phenomenon in the behavior of structures, one needs to apply newer experimental and calculational approaches. The article cites results of modelling and experimental notions on the stage of softening in materials and its role in determining their durability. It is proposed to define the durability of a structurally inhomogeneous material as its capacity of equilibrium deformation beyond its ultimate strength under specified loading conditions. That reflects nonlocality of criteria for the failure of the material, their dependence both on its own properties and the geometry of a structural element. Complete stress-strain diagrams for structural materials of various classes and examples on how the softening stage is realized in structural materials are given.

Abstract: The kinetics of structural relaxation in fragile glass former, Pd46Cu35.5P18.5 BMG, and strong glass former, Zr50Cu40Al10 BMG, was investigated by volume relaxation. The former exhibited a relaxation phenomenon that is well understood by the local topological instability model, while the latter showed monotonous relaxation behavior over a wide range down to Tg-60 K. The discrepancy may be closely related to the difference in the fragility of both glasses.