The elastic energies (
E) of edge dislocations in planes of a 〈111〉 zone axis which are {
pqr}〈111〉 type dislocations, and those of edge and screw dislocations with various Burgers vectors in planes {110} and {112} which are {110}〈
lmn〉 and {112}〈
l′
m′
n′〉 type dislocations in
bcc metals (α-Fe, Fe-Si, Nb, V, Ta, W, Mo, Cr, K, Li, Na) are calculated in terms of an anisotropic elasticity theory.
Among the elastic energies of the {
pqr}〈111〉 type edge dislocations, the energy of a {112}〈111〉 edge dislocation is the maximum and that of a {110}〈111〉 edge one is the minimum for all
bcc metals evaluated. Among the energies of dislocations with three typical Burgers vectors
a⁄2〈111〉,
a〈100〉, and
a〈110〉 in planes {110} and {112}, the following inequalities hold:
Ea⁄2〈111〉<
Ea〈100〉<
Ea〈110〉 for metals with
A>1, where subscripts refer to the Burgers vectors and
A is Zener’s anisotropy factor; when
A<1, the difference between
Ea⁄2〈111〉 and
Ea〈100〉 becomes small, and especially for screw dislocations
Ea〈100〉 is comparable to
Ea⁄2〈111〉. According to the analysis of dislocation reactions, it appears that the
a⁄2〈111〉 and
a〈100〉 type dislocations are stable and the
a〈110〉 type is unstable.
Using these results, the dislocation energies and the choice of the slip system in
bcc metals are discussed on the basis of the criterion of the minimum dislocation energy.
抄録全体を表示