Topic
Bainite
About: Bainite is a research topic. Over the lifetime, 9520 publications have been published within this topic receiving 145305 citations.
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15 May 2003-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, an ultra low carbon Cu bearing HSLA steel, micro alloyed with Nb and Ti was forged in two stages and subsequently cooled at different cooling rates, and the microstructures and the mechanical properties at various cooling rates have been studied.
Abstract: An ultra low carbon Cu bearing HSLA steel, micro alloyed with Nb and Ti was forged in two stages and subsequently cooled at different cooling rates. Variation in microstructures and the mechanical properties at different cooling rates have been studied. Volume fraction of bainitic phase has been found to vary with different cooling rates. Maximum strength was achieved in this steel at an intermediate cooling due to precipitation hardening of very fine microalloying carbides, carbonitrides and e-Cu precipitates. Finer polygonal ferrite and granular bainite structure obtained at the slowest cooling rate resulted in high impact toughness values at ambient and sub ambient temperatures.
64 citations
TL;DR: An X-ray diffractometer study of martensite formed in an 18 wt pct nickel, 0.98 wt Pct carbon austenite single crystal yields the shapes, positions, and integrated intensities of 200, 020, and 002 peaks as mentioned in this paper.
Abstract: An X-ray diffractometer study of martensite formed in an 18 wt pct nickel, 0.98 wt pct carbon austenite single crystal yields the shapes, positions, and integrated intensities of 200, 020, and 002 peaks. Martensite, which forms below − 60 °C, was tempered at successively higher temperatures from −45 to 450 °C. The results show that after subambient aging, during which C atoms in c-oriented octahedral sites have clustered, carbide precipitation starts and small regions (∼30A in the [001]) with negative tetragonality appear. Upon subsequent tempering these are augmented by larger regions which have small positive tetragonality. In this process the “c” lattice parameter changes markedly but the “a” and “b” lattice parameter increase very little. These results indicate the formation of carbon depleted martensite which is coherently strained by the carbide particles. At and just above 100 °C the 200, 020, and 002 peaks all become doublets as the martensite matrix discontinuously breaks free of coherency and becomes highly imperfect ferrite. This change also occurs during the so-called “first stage of tempering.” Further tempering decreases the defect content of this ferrite. The lattice of the martensite is extensively reoriented during tempering just above room temperature. These reorientations probably accommodate the lattice parameter changes described above and may be carried out by movement of twin boundaries.
64 citations
01 Jul 1974-Metallurgical and Materials Transactions B-process Metallurgy and Materials Processing Science
TL;DR: A. Nesbitt and H. Williams: Trans. Appl. Metals, 1970, vol. 8, pp. 904-7. as mentioned in this paper The Trans.
Abstract: 419-42. 2. N. A. Hill and J. W. S. Jones: s NueL Mater., 1961, vol. 3, pp. 138-55. 3. D. L. Douglass: Trans. Amer. Soe. Metals, 1961, vol. 54, pp. 322-30. 4. M. Garfinkle and R. G. Garlick: Trans. TMS-AIME, 1968, vol. 242, pp. 809-14. 5. D. G. Alexander and O. N. Carlson: Trans. TMS-AIME, 1969, vol. 245, pp. 2592-3. 6. E. A. Nesbitt and H. J. Williams: J. Appl. PIjys., 1955, vol. 26, pp. 1217-21. 7. Y. lwama, M. lnagaki and T. Miyamoto: Trans. Japan. Inst. Metals, 1970, vol. 11, pp. 268-74. 8. A. J. Perry and D. J. Rowcliffe: J. Mater. ScL, 1973, vol. 8, pp. 904-7. l o w vo id s e m i c o h e r e n t
64 citations
TL;DR: In this paper, the effect of retained austenite stability on impact-abrasion wear resistance was investigated, and it was demonstrated that a high mechanical stability of retained Austenite brought about improved wear resistance in bainite steels.
64 citations
25 Nov 2006-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the fine structure of martensite/austenite (M/A) islands in pipeline steel X70 was investigated using transmission electron microscopy, and it was shown that the microstructure of the steel undergoing thermo-mechanical controlled processing, comprises a majority of irregular blocky ferrite and acicular ferritic constituents and a small amount of so-called M/A islands which in turn consisted of retained austenite and martensites plates different in size and orientation.
Abstract: The fine structure of martensite/austenite (M/A) islands in pipeline steel X70 was investigated using transmission electron microscopy. It was shown that the microstructure of the steel undergoing thermo-mechanical controlled processing, comprises a majority of irregular blocky ferrite and acicular ferritic constituents and a small amount of so-called M/A islands which in turn consisted of retained austenite and martensite plates different in size and orientation. Microtwins and midrib are usually formed within a martensite plate, which is an indication of the occurrence of high-carbon martensite. It was in addition found that the amount of the M/A islands decreased slightly with increasing the cooling rate after the hot deformation, and the morphology of the M/A islands changed from thick, irregular long strip to thin, short rods. The holding temperature after the fast cooling had no evident effect on the amount of the M/A islands, though lowering the holding temperature could yield a finer and more dispersive M/A islands.
64 citations