Estimation of back stress produced by dislocation interaction in icosahedral Al-Pd-Mn

摘要

We attempted to calculate the breakaway stress σ{sub}b of dislocation from attractive junction made by reaction of dislocations. Assuming that the force facting on the unit length of dislocation with the Burgers vector B under a shear stress τ{sub}a is f =τ{sub}a |b"| where b" is the phonon component of B, and that the elastic energy per unit length of dislocation W is approximated by W = G(|b"|{sup}2 + c{sub}2 |b{sup}⊥|{sup}2) where G is the shear modulus, b{sup}⊥ the phason component of B and c{sub}2 a coefficient of about 3.1×10{sup}(-3). Using the values G = 48.4 GPa at 1070 K, the Taylor factor M= 3 and the measure dislocation density of 1.8×10{sup}13 m{sup}（-2）, we calculated σ{sub}b for 21 possible dislocation reactions. Picking up the most possiNe dislocation reactions, σ{sub}b distributed between 50 and 80 MPa, and the average of them was 64 MPa. This result strongly suggested the possibility that the main part of the internal stress of the high-temperature deformation of icosahedral Al-Pd-Mn is explained by σ{sub}b.