ZONE OF FATIQUE CRACK GROWTH OF STAINLESS STEEL: STRUCTURE-PHASE STATES EVOLUTION
The transmission electron microscopy was used to analyze formation of the structural phase states in the fatigue crack growth area in 08XI8N10T anstenite (0,1％C; 17,5％Cr; 10％N; 1％Ti) stainless steel subjected to high-cycle fatigue.In the initial state up to 75％ of the total volume was occupied by a chaotic dislocation substructure,the rest was shared in equal proportion by reticular and cellular-reticular substructures.Average scalar density of dislocations amounted to 1.5.1010cm-2.Carbide phase was represented by chromium carbides M23C6 sized 0.1-1 Inn comprised of (FeCr)23C6 and TiC with average size of 62±5 nm.High-cycle fatigue testing resulted in higher (up to 5.2* 1010cm-2) scalar density of dislocations in the ruptured zone which increased share of material in the total volume with ordered dislocation substructures against the chaotic ones. In steel fractured after 170 thousand stress cycles the fatigue growth area has the following proportion of dislocation substructures: chaotic-5％,reticular-70％,cells and balls comprise the rest in equal proportion.In strained steel stacking faults and microtwins are formed,channels for slip and twinning steel deformation are triggered.Deformation twinning leads to martensite γ→ε transformation.Steel fatigue loading entails partial dissolution of carbides M23C6 near grain boundaries and isolation of Cr3C2 on carbide interlayer boundaries,as well as coagulation of TiC particles up to 120±7 nm in ruptured state.At the same time their size variety is substantially expanded.Microcracks form near carbide-matrix phase boundaries and within the volume of carbide phase particles that are some nanometers in size.Such locations are stress concentrators which lead to failure of the whole sample.
steel dislocation substructure fatigue
S.V.Vorobev A.V.Gromova Yu.F.Ivanov S.V.Konovalov, K.D.Lukin
Post graduate students Doctor of Physics and Mathematics,Professors,Siberian State University of Industry,654007,Russia,Nov Doctor of Physics and Mathematics,Professors,Siberian State University of Industry,654007,Russia,Nov
国际会议
第二届国际非均质材料力学会议(The Second International Conference on Heterogeneous Material Mechanics)
安徽黄山
英文
435
2008-06-03（万方平台首次上网日期，不代表论文的发表时间）