Accession Number : AD0739709

Title :   Deformation of Field Ion Microscopy Tips by Mechanical Contact.

Descriptive Note : Technical memo.,

Corporate Author : PENNSYLVANIA STATE UNIV UNIVERSITY PARK ORDNANCE RESEARCH LAB

Personal Author(s) : Walko,Robert J.

Report Date : 15 JAN 1971

Pagination or Media Count : 63

Abstract : Tungsten and iridium field ion microscope (FIM) tips served as asperities which were subjected to measurable compressive loads by mechanically contacting them in air to tungsten and platinum plates. FIM tips contacted with tungsten displayed dented regions of irregular shape, where FIM tips contacted to platinum had well designed, nearly circular contact regions. Average contact pressures were calculated. Mechanically induced twinning on the (111) planes of (001) oriented iridium tips was observed to occur for iridium-tungsten and iridium-platinum contacts. This can be explained by an imperfect slip of each layer of the (111) plane into a <112> direction. The critical shear stress necessary for twinning was also estimated. (Author)

Descriptors :   (*FIELD EMISSION, CRYSTAL DEFECTS), (*MICROSCOPY, *CRYSTAL DEFECTS), TUNGSTEN, IRIDIUM, MICROSCOPES, TEST METHODS, DEFORMATION

Subject Categories : Test Facilities, Equipment and Methods

Distribution Statement : APPROVED FOR PUBLIC RELEASE