Deformation modes of proton and neutron irradiated stainless steels

Deformation Structure in Highly Irradiated Stainless Steels

“…Ledge formation and microcracking at grain boundaries were reported in deformed irradiated stainless steels, suggesting that localized deformation is related to grain boundary cracking. 4,7) These previous studies showed the deformation characteristics at doses less than several dpa, where the irradiated materials showed no plastic instability. It is well known that the yield strength saturates at doses near 10 dpa in stainless steels irradiated at approximately 300 C. At doses higher than such level, irradiated stainless steels show extremely low uniform elongation and plastic instability.…”

“…This was consistent with the results of previous studies and could be explained by the lower twinning stress. [6][7][8][9]12) Nanotwins were observed near partially separated grain boundaries (Figs. 12(d) and 12(e)), near cracked channels ( Fig.…”

“…[6][7][8][9][10][11][12] Both dislocation channeling and twinning were identified as deformation modes. The deformation mode was dependent on deformation temperature and strain rate as well as microstructures and extent of deformation.…”

Hydrogen Embrittlement Understood

“…Having such a dense field of obstacles would influence the mobility of dislocations much in the same way that vacancy clusters produced by irradiation influence the behavior-here they result in a strengthening of the matrix and the deformation is restricted to channels in which the defect density is reduced by the passage of dislocations. [96][97][98][99][100] Lastly, there is no experimental evidence, to our knowledge, that demonstrates how a nano-sized vacancy-produced ''void'' can grow to become micron-sized and coalescence with another void to produce fracture. Stresses needed to grow nano-sized voids are in the GPa range, whereas in mild steels embrittlement can occur in the MPa range.…”

Dislocation-Radiation Obstacle Interactions: Developing Improved Mechanical Property Constitutive Models

“…It is well established that neutron radiation damage to structural and cladding materials in current nuclear environments (Generation I and II reactor systems) produces significant mechanical property degradation. [1][2][3][4][5][6][7][8][9][10][11] However, despite the extensive effort which has produced a significant body of knowledge regarding the macroscopic degradation, we lack the physically-based models that are capable of predicting this degradation and materials failure. This is particular apparent as we attempt to predict the material response in the elastic-plastic regime.…”