Shear Deformation Behavior of Heterostructured Materials: Experimental and Numerical Analyses

초록

In this study, the heterogeneous strengthening behavior in shear deformation was experimentally characterized and numerically modeled for the first time. Uniaxial tensile and simple shear tests were conducted to evaluate the mechanical behavior of Al/Steel/Al layered sheet and its monolithic layers. Contrary to expectations, the mechanical behavior of the layered sheet showed more outstanding performance compared to a simple calculation of the rule of mixtures in not only tensile deformation but also shear deformation, proving the heterogeneous strengthening effect in shear deformation as well. Moreover, the yield strength showed similar synergies in tensile and shear deformations, but the shear deformation exhibited a higher additional strengthening effect at the load before reaching fracture. This remarkable outcome is primarily attributed to the formation of a large amount of geometrically necessary dislocations near the heterogeneous interface in shear deformation than at tensile maximum load. Meanwhile, microstructure and deformation mechanism-based constitutive models were applied to finite element simulations of tensile and shear deformations. The numerically predicted stress–strain curves were compared to experimental results, indicating that microstructure-based constitutive models are reasonable for shear stress state as well as uniaxial tension state. Furthermore, dislocation density-based hardening model is better than conventional phenomenological isotropic hardening for extrapolation of large strain in simple shear test. This is mainly due to consideration of microstructural features in dislocation density-based hardening model.

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