The influence of interaction geometry on the obstacle strength of voids and copper precipitates in iron

P. Grammatikopoulos*, D. J. Bacon, Yu N. Osetsky

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Interaction between a 1/2{1 1 1}{1 1 0} edge dislocation and voids or coherent bcc Cu precipitates (diameter D = 2 or 4 nm) in Fe with their centre displaced by±δz from the dislocation glide plane is investigated by computer simulation for temperature T = 0 to 450 K. Voids provide the highest critical stress, τc, when δz = 0. The dislocation climbs up on release when δz ≥ 0, but down when δz < 0. Void-surface facets influence the sense of climb. There is no correspondence between τc and the sense or magnitude of climb. 2 nm precipitates give highest τc when δz < 0 and lowest when δz > 0, due to a combination of the modulus difference and size misfit between bcc Cu and Fe. 4 nm precipitates are partially transformed to fcc structure by the dislocation when T ≤ 300K and δz ≥ 0. Surprisingly, the transformed fraction of Cu at low T is highest for δz = D/2, due to the compressive field of the dislocation. The geometries that produce large transformed fractions result in the lowest τc, in contrast to expectation from previous studies.

Original languageEnglish
Article number015004
JournalModelling and Simulation in Materials Science and Engineering
Volume19
Issue number1
DOIs
StatePublished - Jan 2011
Externally publishedYes

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