Flow Stress and Work Hardening

Size effects under homogeneous deformation of single crystals: A discrete dislocation analysis☆

“…where A is a constant in the range 0.3-0.5 when the athermal component of T is retained (Gil Sevillano, 1993). increase of the flow stress (Fig.…”

Low Cycle Fatigue Behaviour of DP Steels: Micromechanical Modelling vs. Validation

“…The flow curve of individual phases for ferrite and martensite at room temperature is quantified based on a dislocation-based strain hardening model of Rodriguez and Gutierrez [34]. This model emerges from the classical dislocation theory approaches of Bergström [35] and Estrin/Mecking [36] and from the work of Gil-sevillano [37]. The model constants are quantified by Rodriguez [34] and are reported in Equations (1) and (2):…”

Parameter evolution in a continuous Masing approach for cyclic plasticity and its physical interpretation

“…reviewed by Gil Sevillano (2005). Classically, the assumption of a perfectly random distribution of dislocations leads to Taylor's work-hardening approach ðr / ffiffiffi ffi q p Þ that foresees a screening of the stress field of a dislocation by the whole entity of dislocations over a distance of 1= ffiffiffi ffi q p , (Taylor, 1934;Gil Sevillano, 2005). Other sources of internal stress are due to the heterogeneous distribution of dislocations which is observed, e.g.…”

“…Mughrabi considers the different volume fractions of hard (dislocation walls) and soft (cell interiors) dislocation structures to estimate the flow stress (Mughrabi et al, 1976;Mughrabi, 1981Mughrabi, , 1983Mughrabi, , 1987aLaird et al, 1986). Variations of the internal stress are also produced by the differing mechanical behaviour of neighbouring grains or sub-grains with the size D (Gil Sevillano, 2005). Commonly, a HallPetch relationship ðr / D À 1 2 Þ is used to describe the (sub-) grain size influence on the flow stress, (Hall, 1951;Petch, 1953).…”

“…(Kuhlmann-Wilsdorf, 1970). The dependence of the relationship on the relative share of dislocation cells and sub-grains and their size is thoroughly discussed by Thompson (1977) and Gil Sevillano (2005). For a mixture of an ill-defined dislocation cell and a well-defined subgrain structure, as observed for fatigued 2CrMoNiWV, a linear relationship is suggested to be more appropriate (Thompson, 1977).…”