Estimating the Strength of Single-Ended Dislocation Sources in Micron- Sized Single Crystals (Postprint)

摘要

Three-dimensional (3D) discrete dislocation dynamics simulations were used to calculate the effects of anisotropy of dislocation line tension (increasing Poisson's volumes with free surfaces) and to compare them with the strength of double-ended sources of equal length. Their plastic response was directly modeled within a 1um3 volume composed of a single crystal fcc metal. In general, double-ended sources are stronger than single-ended sources of an equal length and exhibit no significant effects from truncating the long-range elastic fields at this scale. The double-ended source strength increases with v, exhibiting an increase of about 50% at v=0.38 (value of Ni) as compared to the value at v=0. Independent of dislocation line direction, for v greater than 0.20, the strengths of single-ended sources depended upon the sense of the stress applied.