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Atomistic simulation for configuration evolution and energetic calculation of crack in body-centered-cubic iron

Published online by Cambridge University Press:  03 March 2011

Li-Xia Cao  and
Chong-Yu Wang
Li-Xia Cao*
Affiliation:
Central Iron and Steel Research Institute, Beijing 100081, People’s Republic of China
Chong-Yu Wang
Affiliation:
International Centre for Materials Physics, Academia Sinica, Shenyang 110016, People’s Republic of China; and Central Iron and Steel Research Institute, Beijing 100081, People’s Republic of China; and Department of Physics, Tsinghua University, Beijing 100084, People’s Republic of China
*
a) Address all correspondence to this author. e-mail: [email protected]
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Abstract

The molecular dynamics method has been used to simulate mode I cracking in body-centered-cubic iron. Close attention has been paid to the process of the atomic configuration evolution of the cracks. The simulation shows that at low temperatures, partial dislocations are emitted before the initiation of crack propagation, subsequently forming the stacking faults or multilayer twins on {112} planes, and then brittle cleavage and extended dislocation nucleation are observed at the crack tip accompanied by twin extension. These results are in agreement with the experimental observation that twinning and fracture processes cooperate at low temperatures. Furthermore, an energetics analysis has been made on the deformation behavior observed at the crack tip. The effect of temperature on the fracture process is discussed. At the higher temperature, plastic deformation becomes easier, and crack blunting occurs. With increasing temperature, the fracture resistance increases, and the effect of the lattice trapping can be weakened by thermal activation.

Keywords

FeFractureSimulation
Type
Articles
Information
Journal of Materials Research , Volume 21 , Issue 10 , October 2006 , pp. 2542 - 2549
Copyright
Copyright © Materials Research Society 2006

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