TY - JOUR
T1 - The influence of interaction geometry on the obstacle strength of voids and copper precipitates in iron
AU - Grammatikopoulos, P.
AU - Bacon, D. J.
AU - Osetsky, Yu N.
PY - 2011/1
Y1 - 2011/1
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=79251577098&partnerID=8YFLogxK
U2 - 10.1088/0965-0393/19/1/015004
DO - 10.1088/0965-0393/19/1/015004
M3 - 文章
AN - SCOPUS:79251577098
SN - 0965-0393
VL - 19
JO - Modelling and Simulation in Materials Science and Engineering
JF - Modelling and Simulation in Materials Science and Engineering
IS - 1
M1 - 015004
ER -