Misfit strains and phase transformations in layered composite solids

Abstract

General formulae are found for misfit strains and their energy density in multilayer solid composites. The effect of misfit strains on phase transformations (related to diffusional mixing) in layered composites is theoretically described with the help of the above general formulae. It is theoretically revealed here that misfit strains play a significant role in initiating solid-state amorphizing transformations. The dependence of the minimal critical thickness (which characterizes the amorphization processes) on misfit parameters in layered composites is found.

Misfit dislocations in multilayered films on disclinated substrates

“…In order to effectively model the behaviour of MDs in nanoscale films on deformed substrates, one should take into account the effects of dislocation cores (see, e.g., [33][34][35]), their possible splitting (see, e.g., [22,[36][37][38]), and amorphization at interphase boundaries (see, e.g., [39,40]). Such effects play an important role in the films and layered composites with vanishingly small film/layer thickness, where the dislocation core diameter and the interphase boundary thickness are close to the film/layer thickness.…”

Interfaces in Nanostructured Films and Coatings

“…Recently, it has been experimentally revealed that the solid state amorphization does not occur in Ni/Ti multilayer composites having the crystalline layer thickness in a composite below some critical thickness h" (being several nanometers) [23]. Solid state amorphizing transformations in layered composites have been theo- retically described in [25] as phase transformations affected by misfit straines. It has been found that there is a misfit-stress-induced minimal critical thickness ha m C which characterizes the solid state amorphization in layered composites: composites consisting of layers with thickness whose values are above h are amorphized, whereas below are not amorphized.…”

Nanoscale defect structures at crystal–glass interfaces

“…Crystal-glass composite materials (bulk composites consisting of crystallites embedded in an amorphous matrix, bulk composites consisting of amorphous particles embedded in a crystalline matrix, multilayer coatings, nanocomposite coatings consisting of nanocrystallites divided by amorphous intergranular layers, amorphous thin films on crystalline substrates, crystalline thin films on amorphous substrates, etc) represent the subject of intense experimental and theoretical research efforts motivated by a wide range of their applications in high technologies; see, e.g., [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Physical and mechanical properties of these composite materials essentially depend on both the structure and behavior of crystal-glass interfaces.…”

“…One of the most important characteristics of a crystal-glass interface is its energy. For instance, the interface energy serves as a key parameter regulating both crystal-to-glass and glass-to-crystal transformations [1][2][3][17][18][19]. Benedictus et al [20] have estimated the energy of crystal-glass interfaces in the framework of the thermodynamic approach, which, however, does not take into account the misfit (geometric mismatch inducing distortions) between the amorphous and crystalline phases.…”