Backtracking Depth-Resolved Microstructures for Crystal Plasticity Identification—Part 2: Identification

Abstract

The present study considers the identification of crystal plasticity parameters from the knowledge of a deformed microstructure, which has been backtracked to the reference state, and known kinematics along the sample surface. This theoretical question is tackled on a numerical (synthetic) test case. A 2D microstructure with one dimension along the depth is generated, and deformed using known crystal plasticity law. A procedure is proposed to perform the calibration of the constitutive parameters addressing the specific challenge of having a partial knowledge of the boundary conditions. The proposed identification strategy combined with the estimation of the reference microstructure is shown to retrieve the constitutive parameters with good accuracy.

Backtracking Depth-Resolved Microstructures for Crystal Plasticity Identification—Part 1: Backtracking Microstructures

“…From the better reconstructed model and with all information available at the surface, crystal plasticity can be studied more precisely. For example, identification based on the backtracked reference configuration results in more precise parameters, than those based on extruded model from surface, according to a companion paper [15].…”

“…The present procedure is designed to estimate the reference configuration from the deformed one assuming that the constitutive law is close to the actual one. It is sketched in Figure 1, which accounts for the left part of Figure 1 in the second part of the study [15]).…”

“…The most important benefit of retrieving the microstructure underneath the surface is for the identification of a constitutive law. This question is addressed in a companion paper [15]. From 3D-EBSD analyses, it is assumed that what is known is the deformed configuration Ω exp def , namely the field of crystal orientation ξ at each material point x of the deformed geometry.…”

Incipient Bulk Polycrystal Plasticity Observed by Synchrotron in-situ Topotomography

“…A detailed parametric study is necessary to analyze the impact of these parameters values on the activation of slip systems in that grain. This can be seen as an opportunity to use such experimental data collected at the length scale of the grains and in the bulk to enrich identification data sets and solve the long standing issue of crystal plasticity material parameter identification [38]. Using the simulated mechanical fields within the grains, rocking curves can be simulated as described in section 2.5.…”

Measuring topographies from conventional SEM acquisitions

“…The topography measurement of nanoindentation with AFM helps for the direct observation of plasticity for different crystal planes [6]. Recent studies show that the precise measurement of the 3D material microstructure and its subsequent deformation, thus including topography, improves identification results of crystal plasticity parameters [7,8].…”