Microstructure characterization of 316L deformed at high strain rates using EBSD

Journal Article · Thu Dec 15 04:00:00 EST 2016 · Materials Characterization

DOI:https://doi.org/10.1016/J.MATCHAR.2016.10.017· OSTI ID:22689662

Specimens from split Hopkinson pressure bar experiments, at strain rates between ~ 1000–9000 s{sup −1} at room temperature and 500 °C, have been studied using electron backscatter diffraction. No significant differences in the microstructures were observed at different strain rates, but were observed for different strains and temperatures. Size distribution for subgrains with boundary misorientations > 2° can be described as a bimodal lognormal area distribution. The distributions were found to change due to deformation. Part of the distribution describing the large subgrains decreased while the distribution for the small subgrains increased. This is in accordance with deformation being heterogeneous and successively spreading into the undeformed part of individual grains. The variation of the average size for the small subgrain distribution varies with strain but not with strain rate in the tested interval. The mean free distance for dislocation slip, interpreted here as the average size of the distribution of small subgrains, displays a variation with plastic strain which is in accordance with the different stages in the stress-strain curves. The rate of deformation hardening in the linear hardening range is accurately calculated using the variation of the small subgrain size with strain. - Highlights: •Only changes in strain, not strain rate, gave differences in the microstructure. •A bimodal lognormal size distribution was found to describe the size distribution. •Variation of the subgrain fraction sizes agrees with models for heterogeneous slip. •Variation of subgrain size with strain describes part of the stress strain curve.

• OSTI ID: 22689662
• Journal Information: Materials Characterization, Journal Name: Materials Characterization Vol. 122; ISSN 1044-5803; ISSN MACHEX
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BACKSCATTERING
DEFORMATION
DIAGRAMS
DISLOCATIONS
ELECTRON DIFFRACTION
GRAIN SIZE
PLASTICITY
STAINLESS STEEL-316L
STRAIN HARDENING
STRAIN RATE
STRAINS
STRESSES
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K