Accession Number : AD0836591

Title :   EFFECT OF DEFORMATION ON EXTINCTION OF ULTRASOUND IN MOLYBDENUM AND NIOBIUM MONOCRYSTALS (VPLYV DEFORMATSIYI NA ZAHASANNYA ULTRAZVUKU V MONOKRYSTALAKH MOLIBDENU I NIOBIYU),

Corporate Author : FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OH

Personal Author(s) : Mordyuk, M. S.

Report Date : 16 NOV 1967

Pagination or Media Count : 8

Abstract : The paper aims to explain the effect of deformation on ultrasound damping in single crystals of Mo and Nb in the form of cylinders and cubes of zone purity with planes removed and heated to 1100C for several hours to relieve polishing stress. Measurements were made at 10 and 30 Mc by the pulse method of crystals deformed by compression perpendicular to the (100) plane and recorded the ultrasonic damping as a function of deformation. In molybdenum slight deformation results in great damping with a maximum at 1% deformation and leveling off at 2%, which is attributed to shortening and widening of the dislocation loop. Ultrasonic damping in Nb rises linearly at both frequencies with no maximum at room temperatures. This is attributed to intense restoration of elastic properties. Further experiments showed restoration of damping in a single crystal of Mo to be insignificant, while it is more pronounced in the deformed Nb specimens. Temperature dependence of the damping factor in single Nb crystals was also studied and found to be of the same order as deformation changes. (Author)

Descriptors :   (*MOLYBDENUM, CRYSTAL STRUCTURE), (*NIOBIUM, CRYSTAL STRUCTURE), DEFORMATION, ULTRASONIC PROPERTIES, SINGLE CRYSTALS, CRYSTAL GROWTH, IMPURITIES, CRYSTAL DEFECTS, TEMPERATURE, COMPRESSIVE PROPERTIES, MEASUREMENT, USSR.

Subject Categories : Physical Chemistry
      Crystallography

Distribution Statement : APPROVED FOR PUBLIC RELEASE