Accession Number : AD0472855

Title :   FIELD ION MICROSCOPY OF FILAMENTARY IRON CRYSTALS.

Descriptive Note : Final rept. Jul 64-May 65,

Corporate Author : PENNSYLVANIA STATE UNIV UNIVERSITY PARK DEPT OF PHYSICS

Personal Author(s) : Mueller ,Erwin W. ; Nishikawa,Osamu

Report Date : AUG 1965

Pagination or Media Count : 17

Abstract : Filamentary iron crystals of the C, D and H Series as furnished by Air Force Materials Laboratory were observed in several cross sections along the total length using the field ion microscope. No change in crystal orientation was noticed for (001), (111) and (110) oriented specimens. The previously discussed amorphous core structure was found to be caused by yield in the (111) region due to the field stress. Hydrogen promoted field evaporation is a means of shaping the tip surface at a reduced field strength so that artifacts can be avoided and perfect (111) planes can be developed. The few dislocations observed place no limit on the strength of the tip core which withstands a field stress of 710 kg/sq mm, or 4% of the bulk modulus. (Author)

Descriptors :   (*IRON, SINGLE CRYSTALS), (*SINGLE CRYSTALS, MICROSCOPY), FILAMENTS, GRAIN STRUCTURES(METALLURGY), CRYSTAL GROWTH, CRYSTAL DEFECTS, HYDROGEN, EVAPORATION, GRAIN BOUNDARIES, HELIUM, LIQUEFIED GASES, STRESSES

Distribution Statement : APPROVED FOR PUBLIC RELEASE