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Micromechanisms of Dynamic Crack Propagation in an AISI 4340 Steel

Godse, R. and Ravichandran, G. and Clifton, R. J. (1989) Micromechanisms of Dynamic Crack Propagation in an AISI 4340 Steel. Materials Science and Engineering A, 112 . pp. 79-88. ISSN 0921-5093. doi:10.1016/0921-5093(89)90346-8.

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The present work is aimed at understanding the micromechanisms of dynamic crack growth at room temperature and a low temperature (−100°C) in an AISI 4340 steel studied by Ravichandran and Clifton. For this purpose, a fractographic and metallographic examination of the specimens used by Ravichandran and Clifton was carried out. Results showed that the steel contained an appreciable amount of upper bainite (about 15%). The study suggests that dynamic crack propagation in the 4340 steel occurs in two stages, i.e. nucleation of microcracks in the upper bainite followed by propagation of these microcracks into the surrounding martensite. At low temperatures, failure of the martensite occurs by cleavage whereas, at room temperature, it occurs by shear localization, leading to microvoid growth and coalescence. At both temperatures, bainitic microcracks serve as failure initiation sites and reduce the dynamic fracture toughness of the steel.

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Ravichandran, G.0000-0002-2912-0001
Additional Information:© 1989 Elsevier Sequoia. Received July 18, 1988; in revised form November 10, 1988. This research was supported by the Army Research Office. Central facilities support was provided through the National Science Foundation Materials Research Group at Brown University.
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Army Research Office (ARO)UNSPECIFIED
Record Number:CaltechAUTHORS:20150225-154649661
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Official Citation:R. Godse, G. Ravichandran, R.J. Clifton, Micromechanisms of dynamic crack propagation in an AISI 4340 steel, Materials Science and Engineering: A, Volume 112, June 1989, Pages 79-88, ISSN 0921-5093, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:55218
Deposited By: Cheryl Gause
Deposited On:02 Mar 2015 23:19
Last Modified:10 Nov 2021 20:43

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