| Numéro |
J. Phys. Colloques
Volume 47, Numéro C2, Mars 1986
32 nd International Field Emission Symposium / 32ème Symposium International d'Emission de Champ
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| Page(s) | C2-233 - C2-238 | |
| DOI | https://doi.org/10.1051/jphyscol:1986235 | |
J. Phys. Colloques 47 (1986) C2-233-C2-238
DOI: 10.1051/jphyscol:1986235
A STUDY OF PRECIPITATION AND SEGREGATION ON AN ATOMIC SCALE OF 11at% Cr-lat% Mo HEAT RESISTING STEEL BY ATOM-PROBE AND TEM
N. IGATA1, S. SATO1, T. ANDO1, T. HASHIZUME2, T. SAKURAI2 et H.W. PICKERING31 Department of Materials Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo, Japan
2 The Institute for Solid State Physics, The University of Tokyo, Minato-ku, Tokyo, Japan
3 Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802, U.S.A.
Abstract
An 11at.%Cr-lat.%Mo commercial steel which contains C, Si, Mn, Nb and V as minor elements was investigated by atom-probe (AP) and transmission electron microscope (TEM). This steel has an excellent heat resisting property at 600 - 650°C but there is a problem in ductile - brittle transition in this temperature range. The following results were obtained : (1) After solution treatment the FIM image was homogeneous on an atomic scale. (2) After tempering at 650°C for 1hr the precipitate was detected. Our AP analysis showed that the precipitate was to be M(C+N) which includes Nb, Cr, V, Mo, Fe, C and N. (3) After tempering at 700°C for 1hr, the precipitate with Fe/Cr ratio 46/42 (sigma phase) was detected. (4) After tempering at 700°C for 1hr the precipitate Fe/Cr ratio 60/40 (sigma phase) was also observed at the lath boundary and adjacent to this region chromium concentration decreased to 1%.