On the Crystal Perfection of Iron Whiskers

摘要

The density and distribution of dislocations in tip grown iron whiskers produced by the hydrogen reduction of liquid iron halide salts has been measured by means of x‐ray rocking curves. The data show that the more perfect whiskers have dislocation densities below 106 dislocation lines per cm2. Thus, many of these whiskers which are less than 10 μ in diameter would contain, at most, only a small number of dislocations and should behave as perfect crystals. No evidence of a large elastic twist was found in any of the whiskers as would be expected for a whisker grown by a screw dislocation mechanism. This did not completely prove that iron whiskers must grow, therefore, by a mechanism based on coherent two‐dimensional nucleation as there are combinations of specific types of screw dislocations which will not produce elastic twists in the whiskers.