J. Mater. Sci. Technol. ›› 1991, Vol. 7 ›› Issue (1): 35-39.

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Dislocation Behaviour near the Crack Tip in Bulk Fe-3% Si Single Crystal

XU Yongbo HA Kuanfu WANG Zhongguang YANG Chunsong DAI Zhongling Laboratory for Fatigue and Fracture of Materials,Institute of Metal Research,Academia Sinica,Shenyang,110015,China.Jilin University,Changchun,130023,China.To whom correspondence should be add   

  1. LaboratoryforFatigueandFractureofMaterials,InstituteofMetalResearch,AcademiaSinica.Towhomcorrespondenceshouldbeaddressed.;JilinUniversity,Changchun,130023,China.;LaboratoryforFatigueandFractureofMaterials,InstituteofMetalResearch,AcademiaSinica,Shenyang,110015,China.;LaboratoryforFatigueandFractureofMaterials,InstituteofMetalResearch,AcademiaSinica,Shenyang,110015,China.;LaboratoryforFatigueandFractureofMaterials,InstituteofMetalResearch,AcademiaSinica,Shenyang,110015,China.
  • 收稿日期:1991-01-28 修回日期:1991-01-28 出版日期:1991-01-28 发布日期:2009-10-10

Dislocation Behaviour near the Crack Tip in Bulk Fe-3% Si Single Crystal

XU Yongbo HA Kuanfu WANG Zhongguang YANG Chunsong DAI Zhongling Laboratory for Fatigue and Fracture of Materials,Institute of Metal Research,Academia Sinica,Shenyang,110015,China.Jilin University,Changchun,130023,China.To whom correspondence should be add   

  • Received:1991-01-28 Revised:1991-01-28 Online:1991-01-28 Published:2009-10-10

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摘要： <正> An investigation has been made of the disloca-tion distribution and dislocation free zone near thecrack tip in bulk Fe-3% Si single crystal duringdeformation in SEM.It has been found that anumber of dislocations were emitted from the cracktip during deformation.After that,the dislocationsmoved rapidly away from the crack tip,which indi-cated that they were strongly repelled by the stressfield at the crack tip.Between the crack tip and theplastic zone there is a region of dislocation-free,which is referred to as dislocation-free zone (DFZ).The length of DFZs is roughly estimated 100μm which is much longer than that found in thinfoil specimen.The variation of dislocation densityas a function of the distance from the crack tip wasmeasured,which showed that the dislocations areinversely piled up in the plastic zone.The length ofDFZs increased with both the length of pre-crackand the amplitude of applied stress.

Abstract: An investigation has been made of the disloca- tion distribution and dislocation free zone near the crack tip in bulk Fe-3% Si single crystal during deformation in SEM.It has been found that a number of dislocations were emitted from the crack tip during deformation.After that,the dislocations moved rapidly away from the crack tip,which indi- cated that they were strongly repelled by the stress field at the crack tip.Between the crack tip and the plastic zone there is a region of dislocation-free, which is referred to as dislocation-free zone (DFZ). The length of DFZs is roughly estimated 100 μm which is much longer than that found in thin foil specimen.The variation of dislocation density as a function of the distance from the crack tip was measured,which showed that the dislocations are inversely piled up in the plastic zone.The length of DFZs increased with both the length of pre-crack and the amplitude of applied stress.

Key words: dislocation, crack tip, DFZ, Fe-3%Si single crystal