The effects of twins on the large strain deformation and fracture of hexagonal close packed crystalline materials

Abstract

We investigated how twin modes in hexagonal close packed materials can affect large inelastic strain behavior and fracture. We considered the two twin mode systems of and (0001) in zircaloy-2, with each mode having 24 unique twin systems. We then incorporated these twin and parent slip systems with a dislocationdensity crystalline plasticity, a non-linear finite-element, and fracture framework that accounts for crack nucleation and propagation. We investigated how these twin modes affect the interrelated effects of crack nucleation and propagation, dislocation density and inelastic slip evolution, stress accumulation, and lattice rotation. The predictions indicate that twin modes significantly affect local deformation and fracture behavior, and, therefore, are essential for the accurate representation of behavior at different physical scales in heterogeneous crystalline hexagonal close packed systems.

Research Progress on Slip Behavior of α-Ti under Quasi-Static Loading: A Review

“…Twins result in more slip systems activation than parent grains, interfacial mismatches and localized stress-strain fields with the matrix, which leads to higher strength and ductility [90,91]. Twinning has an extremely important influence on the entire deformation process.…”