Heterogeneous plastic deformation and Bauschinger effect in ultrafine-grained metals: atomistic simulations

Abstract

The effect of the dislocation density on yield strength and subsequent plastic deformation of ultrafine-grained metals was investigated in large-scale atomistic simulations. Polycrystalline models were constructed and uniaxial tension and compression were applied to elucidate the heterogeneous plastic deformation and the Bauschinger effect. The initial yield becomes heterogeneous as the dislocation density decreases owing to a wide range of Schmid factors of activated slip systems in each grain. A different mechanism of the Bauschinger effect was proposed, where the Bauschinger effect of ultrafine-grained metals is caused by the change in dislocation density in the process of forward and backward loadings.

In Situ TEM Observation of Cooperative Grain Rotations and the Bauschinger Effect in Nanocrystalline Palladium

“…This leads to an inhomogeneous stress distribution and buildup of back stresses at grain boundaries. The heterogeneity of the microstructure in terms of differences in grain size, grain orientation, grain boundary type, and orientation leads to this heterogeneous stress development, which is driving the BE in agreement with previous reports on the BE in thin metallic films [ 32 , 46 , 49 ]. This is also driving the observed backward rotation during unloading fitting to the mechanical response of the thin nc Pd film ( Figure 3 ).…”

Attenuation of the Bauschinger effect and enhancement of tension–compression asymmetry in single crystal aluminum by temperature

“…Yue 17 et al investigated the reversible motion of dislocations caused by pre-dislocation reverse loading. Tsuru 18 et al investigated the effect of dislocation density on the yield strength and plastic deformation of ultrafine crystalline metals. Its Bauschinger effect was found to be due to uneven deformation due to the change in dislocation density between forward and reverse loading.…”

Mechanical, microstructural and in-situ neutron diffraction investigations of equi-biaxial Bauschinger effects in an interstitial-free DC06 steel

“…The associated Bauschinger effect is typically characterized by a decrease in yield strength after the change in load path (Bauschinger, 1886). Many research studies from the last decades (Bate and Wilson, 1986;Buckley and Entwistle, 1956;Caceres et al, 1996;Margolin et al, 1978;Masing, 1926;Mughrabi, 1983;Sleeswyk and Kemerink, 1985;Tan et al, 1994) as well as recent publications (Bagherpour et al, 2020;Demir and Raabe, 2010;Hou et al, 2022;Hu et al, 2017;Kostryzhev et al, 2010; S. W. Lewandowska, 2003;Marcadet and Mohr, 2015;Richards et al, 2011;Tsuru et al, 2016;Vincze et al, 2005) deal with various forms of Bauschinger effects and discuss potential mechanisms related to this extraordinary material behavior. Different microstructural models have been developed to explain the Bauschinger effect.…”