Postprint version. Published in Scripta Metallurgica et Materialia, Volume 26, Issue 6, March 15, 1992, pages 939-944.
NOTE: At the time of publication, the author Blair London was not yet affiliated with Cal Poly.
The definitive version is available at https://doi.org/10.1016/0956-716X(92)90686-9.
Materials Science and Engineering