The development of dislocation structures in the plastic zone ahead of a crack tip has been in- vestigated in a duplex stainless steel during in-situ deformation experiments in a scanning transmission electron microsc...The development of dislocation structures in the plastic zone ahead of a crack tip has been in- vestigated in a duplex stainless steel during in-situ deformation experiments in a scanning transmission electron microscope.It was found that the dislocation distribution was significantly different in the ferrite and in the austenite.In the ferrite grains,the dislocations emitted by the crack tip may cross-slip out of the original slip planes and form a broad plastic zone.However,in the austenite,the dislocation free zone is small and the dislocations emitted by the crack pile up in its slip plane.The selection of slip systems at the crack tip depends on the crack tip Schmid factors in both phases.But after large deformation,the selection of the second slip systems at the craek tip in austenite does not depend on the Schmid factors.展开更多
The alteration of substructure of an austenitic stainless steel has been investigated during con- stant strain fatigue.No plateau stage on the cyclic stress-strain curve was observed for the stainless steel in contras...The alteration of substructure of an austenitic stainless steel has been investigated during con- stant strain fatigue.No plateau stage on the cyclic stress-strain curve was observed for the stainless steel in contrast with a monocrystalline pure copper specimen.This may relate to its low stacking fault energy.During strain fatigue under various amplitudes the substructure of dislocation in austenite alterates correspondingly.It revealed to associate with the appearance change of the cyclic stress-strain curve.展开更多
文摘The development of dislocation structures in the plastic zone ahead of a crack tip has been in- vestigated in a duplex stainless steel during in-situ deformation experiments in a scanning transmission electron microscope.It was found that the dislocation distribution was significantly different in the ferrite and in the austenite.In the ferrite grains,the dislocations emitted by the crack tip may cross-slip out of the original slip planes and form a broad plastic zone.However,in the austenite,the dislocation free zone is small and the dislocations emitted by the crack pile up in its slip plane.The selection of slip systems at the crack tip depends on the crack tip Schmid factors in both phases.But after large deformation,the selection of the second slip systems at the craek tip in austenite does not depend on the Schmid factors.
文摘The alteration of substructure of an austenitic stainless steel has been investigated during con- stant strain fatigue.No plateau stage on the cyclic stress-strain curve was observed for the stainless steel in contrast with a monocrystalline pure copper specimen.This may relate to its low stacking fault energy.During strain fatigue under various amplitudes the substructure of dislocation in austenite alterates correspondingly.It revealed to associate with the appearance change of the cyclic stress-strain curve.
