Origin of the Bauschinger Effect in Amorphous Solids

Sylvain Patinet (1) , Armand Barbot (1) , Matthias Lerbinger (1) , Damien Vandembroucq (1) , Anaël Lemaître (2)

1 PMMH - Physique et mécanique des milieux hétérogenes (UMR 7636)
2 NAVIER UMR 8205 - Laboratoire Navier

We study the structural origin of the Bauschinger effect by accessing numerically the local plastic thresholds in the steady-state flow of a two-dimensional model glass under athermal quasistatic deformation. More specifically, we compute the local residual strength, ∆τc, for arbitrary loading orientations and find that plastic deformation generically induces material polarization, i.e., a forward-backward asymmetry in the ∆τc distribution. In steady plastic flow, local packings are on average closer to forward (rather than backward) instabilities, due to the stress-induced bias of barriers. However, presumably due to mechanical noise, a significant fraction of zones lie close to reverse (backward) yielding, as the distribution of ∆τ c for reverse shearing extends quasilinearly down to zero local residual strength. By constructing an elementary model of the early plastic response, we then show that unloading causes reverse plasticity of a growing amplitude, i.e., reverse softening, while it shifts away forward-yielding barriers. This result in an inversion of polarization in the low-∆τ c region and, consequently, in the Bauschinger effect. This scenario is quite generic, which explains the pervasiveness of the effect.

Domaines: Physique [physics]; Science des matériaux [cond-mat.mtrl-sci]

Sylvain Patinet, Armand Barbot, Matthias Lerbinger, Damien Vandembroucq, Anaël Lemaître. Origin of the Bauschinger Effect in Amorphous Solids. Physical Review Letters, 2020, 124 (20), ⟨10.1103/PhysRevLett.124.205503⟩. ⟨hal-02991521⟩