Assessment of crystal plasticity finite element simulations of the hot deformation of metals from local strain and orientation measurements

Abstract

a b s t r a c tSimulations of the deformation of microstructures at high homologous temperatures have been carried out using a Crystal Plasticity Finite Element (CPFE) model to predict texture and grain structure deformation in Face-Centred-Cubic (FCC) metals deformed under conditions representative of hot forming operations. Results show that the model can quantitatively predict the location and intensity of the main deformation texture components of a AA5052 aluminium alloy deformed at 300 C under Plane Strain Compression (PSC). Simulations also reasonably predict the range of strain values measured using microgrids in the microstructure of a Fe-30wt%Ni alloy deformed at 1000 C using a new experimental procedure. However, the model fails to reproduce accurately intra-granular strain distribution patterns. Results at room temperature, after a tensile test carried out inside a Scanning Electron Microscope (SEM) on the same model alloy, show a much closer match between simulation and experimental results. Despite discrepancies for some local deformation features, the model predicts the formation of intense deformation bands running at 45 with respect to the tensile axis and located along the same grain boundaries as in the experiment. Results, therefore, highlight the limitations of deterministic CPFE simulations for situations where the grain size to sample thickness ratio is small and for which the sub-surface grain geometry strongly affects surface strains. They also show that reliable predictions of the statistical response of a polycrystalline aggregate can be obtained for the hot deformation of metals which controls microstructure evolution during the processing of metals.

An analysis of macro- and micro-scale residual stresses of Type I, II and III using FIB-DIC micro-ring-core milling and crystal plasticity FE modelling

“…It is well known that the crystal plasticity activity is highly dependent on the local orientation of the material, besides the external load applied [59,60]. In fact, in all the crystalline structures there is always a specific slipping plane that is more prone to resolve shear stress.…”

A framework for material calibration and deformation predictions applied to additive manufacturing of metals

“…atom force microscopy (AFM) when using nanoindentation experiments (Zambaldi et al 2012;Schmaling and Hartmaier 2012). Other researchers have used local texture measures to verify crystal plasticity simulations (Pinna et al 2015). For large-scale deformation, DIC or the necking shape would provide valuable calibration data (Cortese et al 2017), which could be used in future implementations of the framework.…”

Efficient fast Fourier transform-based numerical implementation to simulate large strain behavior of polycrystalline materials

“…The sections above describe the general Asaro and Needleman (1985) framework that has been used in various homogenization as well as in full-field schemes (Inal, 2002;Inal et al, 2010;Brahme et al, 2011;Izadbakhsh et al, 2011;Inal and Mishra, 2012;Cyr et al, 2015;Muhammad et al, 2015;Pinna et al, 2015). This formulation, coupled with a rate tangent semi-explicit integration scheme is implemented into a FFT-based model as described next.…”