The Role of Plasticity in the Transverse Lattice Strain Evolution of a Martensitic Steel

A multi-scale crystal plasticity model for cyclic plasticity and low-cycle fatigue in a precipitate-strengthened steel at elevated temperature

“…As shown by Franciosi et al (2015) and also in the work of Ali et al (2011) and Marichal et al (2013), for bcc metals ⟨111⟩ is the slip direction and the {110} slip planes are the primary slip planes. In addition, there is no retained austenite in the P91 steels, which can be confirmed by our recent neutron diffraction measurement (Li et al, 2014b) and the synchrotron pattern of Wang et al (2014). Therefore, for computational efficiency (bearing in mind the large numbers of blocks and sub-grains in the meso-and microscale models), the present model assumes that slip occurs only on {110} planes.…”

“…The current work is based on previous developments, including previously published identification and calibration against measured monotonic test data for P91 up to 600 • C (Li et al, 2014a;Golden et al, 2015a). The validation of the polycrystal FE model for monotonic loading has been carried out using in-situ neutron diffraction measurement (Li et al, 2014b) and ex-situ EBSD measurement (Golden et al, 2015b) for room temperature behaviour. Table 1 gives the elastic constants, flow parameters and the strain hardening parameters used in this work.…”

Experimental study and multiscale modelling of the high temperature deformation of tempered martensite under multiaxial loading

“…A crystal plasticity model is used to represent the constitutive behaviour at the microscale, using the slip system based modelling framework of Asaro and Rice, 1977, implemented via an Abaqus UMAT (Cheong and Busso, 2006;Golden et al, 2016, Li et al, 2014a, 2014b. The crystal plasticity model described below is based on a slip system (Schmidt rule) model, to predict the plastic deformation of crystalline materials.…”

Microscale deformation of a tempered martensite ferritic steel: Modelling and experimental study of grain and sub-grain interactions

“…In [34,35] a physically-based micro-mechanical model was used to analyse a martensitic steel, with grain boundary interactions and the evolution of dislocation density examined numerically using a 'constructed microstructure'. In [36] a microstructurally based material model was used to predict the lattice (elastic) stress/strain response of a martensitic steel with the results validated by in-situ neutron diffraction measurements. The model was also used in [37] to investigate lath size effects in a martensitic steel (P91).…”

“…As in previous work a finite-element (FE) approach is used, with an explicit representation of the material microstructure, focusing at the block level. In [36][37][38][39][40], uniaxial loading of P91 was considered, with validation through neutron diffraction measurements in [40]. In this work, we consider a complex multiaxial loading condition (notched three point bend) with validation carried out both at the macroscale, through overall specimen deformation and notch opening, and at the microscale thourgh EBSD measurements.…”