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 scanningtransmission electron microscop...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 scanningtransmission electron microscope.It was found that the dislocation distribution wassignificantly different in the ferrite and in the austenite.In the ferrite grains,the dislocationsemitted by the crack tip may cross-slip out of the original slip planes and form a broad plasticzone.However,in the austenite,the dislocation free zone is small and the dislocations emittedby the crack pile up in its slip plane.The selection of slip systems at the crack tip depends onthe crack tip Schmid factors in both phases.But after large deformation,the selection of thesecond 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 thestainless steel in contrast ...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 thestainless steel in contrast with a monocrystalline pure copper specimen.This may relate to itslow stacking fault energy.During strain fatigue under various amplitudes the substructure ofdislocation in austenite alterates correspondingly.It revealed to associate with the appearancechange 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 scanningtransmission electron microscope.It was found that the dislocation distribution wassignificantly different in the ferrite and in the austenite.In the ferrite grains,the dislocationsemitted by the crack tip may cross-slip out of the original slip planes and form a broad plasticzone.However,in the austenite,the dislocation free zone is small and the dislocations emittedby the crack pile up in its slip plane.The selection of slip systems at the crack tip depends onthe crack tip Schmid factors in both phases.But after large deformation,the selection of thesecond 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 thestainless steel in contrast with a monocrystalline pure copper specimen.This may relate to itslow stacking fault energy.During strain fatigue under various amplitudes the substructure ofdislocation in austenite alterates correspondingly.It revealed to associate with the appearancechange of the cyclic stress-strain curve.
