FTMP場の理論に基づくミルフィーユ構造におけるキンク形成とエネルギ解放特性に関するマルチスケールシミュレーション

抄録

Kink-strengthening for mille-feuille structures has attracted many attentions in recent years. This study aims at identifying the kink formation/strengthening mechanisms via numerical reproductions of emerging kink-like morphologies based on FTMP (Field Theory of Multiscale Plasticity)-incorporated FE simulations, where incompatibility-based relevant underlying microscopic degrees of freedom for twinning are introduced, in addition to the slip modes. The targeted phenomena here include an experimentally-observed unique feature recently reported based on the combined ND–AE (neutron diffraction - acoustic emission) technique, i.e., scale-free-like energy release before (precursor) and during kink formations. This study uses a Mg single crystal model with alternatingly aligned soft and hard layers in parallel to the basal plane under c-axis plane-strain compression, where the soft/hard regions are controlled by the activity/inactivity of the twin model. The simulated results are demonstrated to exhibit power-law type distributions both in the strain energy fluctuation and the incompatibility from the early stage of deformation even before the massive emergence of kink-like regions, which are analogous to the above-mentioned ND–AE observations. They lead us to tentatively conclude that the layered structure associated with the incompatibility-based relevant degrees of freedom, in addition to a sufficient constraint of the basal slip activity, can play pivotal roles in reproducing the targeted feature.