Crystal Plasticity Modeling of Duplex Steels at High Temperatures

Abstract

The paper considers physical approach to the description of inelastic deformation of two-phase polycrystalline materials – duplex steels. Such approach is based on the introduction the key mechanisms of inelastic deformation in explicit way. The main mechanism of plastic deformation is slipping of edge dislocations. The structure of duplex steel consists of austenite and ferrite phases. At high temperatures ferrite reveals dynamic recovery (DRV) and austenite ability to undergo dynamic recrystallization (DRX). The way to describe DRV and DRX processes within the multilevel approach of elastoviscoplastic modeling is proposed. Obtained results of numerical experiments of uniaxial compression deformation at different temperatures have good qualitative agreement with experimental data.

Large Delta T Thermal Cycling Induced Stress Accelerates Equilibrium and Transformation in Super DSS

“…The complexity increases because of the simultaneous presence of δ and γ phases in DSS. Some reports have indicated that the ferrite phase of DSS exhibits dynamic recovery (DRV) at high temperatures, and the austenite phase of DSS dynamic recrystallization (DRX) [29,30]. Because γ has a lower yield stress than δ in DSS, thermal stress-induced plastic deformation occurred earlier at the γ grains.…”

“…The degree of local crystalline misorientation within each grain was determined by the illustrated color-typed code. Red (5 • ) corresponds to the highest misorientation, whereas blue (0 • ) corresponds to the grains without any misorientation [29]. In Figure 7, the KAM maps show the misorientation at the interfaces between the γ, δ, and σ phases, in an order of the as-received (Figure 7a), 2SS (Figure 7b), 2SS + 3 cycles (Figure 7c), 2SS + 7 cycles (Figure 7d), 2SS + 13 cycles (Figure 7e), and 2SS + 20 cycles (Figure 7f) from 0 • to 5 • .…”

“…In the 2SS + 20 cycles condition, the σ formation induced a higher KAM strain at the σ grain boundary than at the δ and γ grain boundaries, as shown in Figure 7f. The blue mapping inset in Figure 7 represents the grain region adjacent to the boundary with a very low dislocation density [29]. Generally, the high dislocation density results in a subgrain angle > 1 • [40][41][42][43] which can lead to the deformed grains having KAM > 1 • , whereas the recrystallized grains have KAM < 1 • .…”