Initial Examination of the Strength of Single-Ended Sources in Micrometer-Sized Single Crystals (Preprint)
UES INC DAYTON OH
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A recent study indicated that the behavior of single-ended dislocation sources contributes to the flow strength of micrometer-scale crystals. In this study 3D discrete dislocation dynamics simulations are used to calculate the effects of anisotropy of dislocation line tension on the strength of single-ended dislocation sources in micrometer-sized volumes with free surfaces, and to compare them with the strength of double-ended sources of equal length. This is done by directly modeling their plastic response within a 1-micron cubed 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 Poisson ratio, exhibiting an increase of about 50 at v 0.38 value for 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 depend upon the sense of the stress applied.