The theory of mechanism-based strain gradient plasticity was generalized here in order to account for the effect of intrinsic lattice resistance in the Taylor dislocation model. A multiscale hierarchical framework was used to link the strain gradient plasticity theory at the mesoscale to the Taylor dislocation model at the microscale. It was established that the interaction between the strain gradient effect and the friction stress (intrinsic lattice resistance) was weak. The hardness increase due to intrinsic lattice resistance was nearly independent of the strain gradient effect. The linear relationship between the square of the micro-indentation hardness and the reciprocal of indentation depth was extended in order to explain experimental data on body-centered cubic W; where the effect of intrinsic lattice resistance played a significant role.

Effect of Intrinsic Lattice Resistance in Strain Gradient Plasticity. X.Qiu, Y.Huang, W.D.Nix, K.C.Hwang, H.Gao: Acta Materialia, 2001, 49[19], 3949-58