Influence of Features of Interphase Boundaries on Mechanical Properties and Fracture Pattern in Metal–Ceramic Composites

Overcoming the limitations of distinct element method for multiscale modeling of materials with multimodal internal structure

“…The geometric and physical and mechanical properties of such interfaces depend on the characteristic size of the structural elements separated by interfaces as well as on the conditions of material production. Particularly, the characteristic width of grain boundaries does not exceed a few nanometers, whereas the width of phase interfaces may vary within several orders of magnitude and reach a few micrometers (as is observed, e.g., in sintered metal-ceramic composites [49]). The ''wide'' phase interfaces have a pronounced gradient of the internal nanostructure (vacancy and dislocation densities, secondary nanoinclusions) and mechanical properties in transition from one phase to another [50][51][52][53].…”

Fractography of the fatigue fracture surface of silumin irradiated by high-intensity pulsed electron beam

“…Consequently, the generation energy in the surface layer of stress concentrators increases greatly, and the probability of formation in the surface layer of the defective substructure decreases. In other words, the formation of multi-level structural-phase state determines the manifestation in the surface layer of the modified silumin of damping properties with regard to the base material by external mechanical and thermal influences, preventing premature nucleation of fragile microcracks and their propagation from the surface into the main volume of material leading to the formation of the main cracks and fracture of the base material [13]. …”

Comparative analysis of different models of interphase boundaries in metal-ceramic composites

“…In the framework of this approximation, mechanical properties of the interface are determined by the cohesive constitutive relationships in terms of traction-separation or potential-separation laws [2]. Here, we consider a simplified realization of the widely used nonpotential-based model of Geubelle and Baylor [3,4].…”

“…"Thermally" induced GNDs lead to an increase in the value of yield stress y , while the geometrical mismatch induced GNDs cause an increase in the strain-hardening coefficient K [5,6]. The third approximation assumes the gradient of the mechanical properties in the interface shell when passing from the inclusion surface towards the unmodified matrix (normal to the inclusion surface at that point) [4]. This gradient may be associated with the transition region of a variable composition of chemical elements at the interphase boundary [4,7], as well as with secondary nanoparticles in the vicinity of an inclusion.…”

“…The third approximation assumes the gradient of the mechanical properties in the interface shell when passing from the inclusion surface towards the unmodified matrix (normal to the inclusion surface at that point) [4]. This gradient may be associated with the transition region of a variable composition of chemical elements at the interphase boundary [4,7], as well as with secondary nanoparticles in the vicinity of an inclusion. The yield stress and the strain-hardening coefficient of interface material have maximum magnitudes at the border with the inclusion surface and decrease down to the values corresponding to the unmodified matrix at the outer border of the interface shell.…”