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不锈钢微裂纹形核扩展的TEM原位观察
引用本文:李红旗,陈奇志,褚武扬.不锈钢微裂纹形核扩展的TEM原位观察[J].金属学报,1996,32(11):1159-1164.
作者姓名:李红旗  陈奇志  褚武扬
作者单位:北京科技大学,北京科技大学材料物理系
摘    要:310奥氏体不锈钢在透射电镜中的原位拉伸观察表明,如在裂尖发射位错后保持恒位移,则在裂尖能形成无位错区,这个弹性的DFZ不均匀减薄,其应力集中可等于原子键合力,从而导致纳米微裂纹在DFZ中形核,并很快钝化成空洞,如果裂尖发射位错后继续拉伸,则上述基本过程被掩盖,仅看到交滑移使裂尖区减薄,从而导致微米给空洞或裂纹的形核和连接。如稍稍卸载,则可观察到裂尖前反塞积位错群的逆返现象。

关 键 词:不锈钢  TEM  裂纹  形核扩展  微裂纹
收稿时间:1996-11-18
修稿时间:1996-11-18

IN SITU TEM OBSERVATION OF NUCLEATING AND PROPAGATING OF MICROCRACKS IN STAINLESS STEEL UNDER TENSION
LI Hongqi,CHEN Qizhi,CHU Wuyang.IN SITU TEM OBSERVATION OF NUCLEATING AND PROPAGATING OF MICROCRACKS IN STAINLESS STEEL UNDER TENSION[J].Acta Metallurgica Sinica,1996,32(11):1159-1164.
Authors:LI Hongqi  CHEN Qizhi  CHU Wuyang
Affiliation:LI Hongqi,CHEN Qizhi,CHU Wuyang(University of Science and Technology Beijing,Beijing )
Abstract:TEM in situ tensile tests of 310 stainless steel show that a dislocation free zone (DFZ) forms after equilibrium if the displacement keeps constant after many dislocations are emitted from a crack tip. The elastic DFZ is gradually thinned and the stress in DFZ will reach the cohesive strength resulting in nucleating of nanocracks in DFZ and blunting into voids. If continuously tensioning after crack tip emitted dislocations, and inhomogeneously thinning ahead of crack tip, then initiating and connecting of micro-voids(or micro-cracks) will be observed rather than DFZ, initiating of nanocracks and nanocracks' blunting into voids. The inversely piled-up dislocations ahead of a loaded crack tip can move towards the crack tip if unloading a little.
Keywords:stainless steel  in situ TEM tension  dislocation free zone  initiation of
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