Plasticity in solids is dependent on microstructural history, temperature, and loading rate, sample-dependent knowledge of yield points structural materials adds reliability to mechanical behavior. Yielding commonly measured through controlled testing, ways that either distinguish elastic (stress) from total deformation measurements or identify plastic slip contributions. In this paper, we show...

A single crystal plasticity theory for insertion into finite element simulation is formulated using sequential laminates to model subgrain dislocation structures. It is known that local models do not adequately account for latent hardening, as latent hardening is not only a material property, but a nonlocal property (e.g. grain size and shape). The addition of the nonlocal energy from the forma...

Grain structure plays a key role in the mechanical properties of alloy materials. Engineering grain requires comprehensive understanding evolution boundaries (GBs) when material is subjected to various manufacturing processes. To this end, we present computationally efficient framework describe co-evolution bulk plasticity and GBs. We represent GBs as diffused geometrically necessary dislocatio...

Recent experimental studies on nanocrystalline metals have shown that mechanical strength may decrease with decreasing grain size d for d,10– 15 nm. The mechanisms underlying this trend are not understood, although such a relationship is in distinct contrast to that seen in microcrystalline metals whereby strength increases with decreasing grain size. Here, we present direct experimental observ...

Hysteresis loop curves are highly important for numerical simulations of materials deformation under cyclic loadings. The models mainly take account of only the tensile half of the stabilized cycle in hysteresis loop for identification of the constants which don’t vary with accumulation of plastic strain and strain range of the hysteresis loop. This approach may be quite erroneous particularly ...

Abstract Size effects in metal plasticity are widely accepted, and different theoretical approaches to handle the phenomenon developing literature. The present work considers Fleck Willis (2009b) framework, creates a new gradient enhanced rate-independent crystal FE-implementation. study both energetic dissipative hardening strengthening, adopts general form of effective slip rate. Monotonic cy...

for an Invited Paper for the MAR11 Meeting of The American Physical Society Influence of edge structure, substrate structure and grain boundaries on the electronic properties of graphene quantum dots and transferred graphene1 JOSEPH LYDING, University of Illinois We have used UHV STM to study the quantum size effect gap and the effects of edge electronic structure on graphene quantum dots (GQDs...