Accession Number : AD0430167


Title :   THE STUDY OF THE STRUCTURAL AND TRANSFORMATION CHARACTERISTICS OF THE PRESSURE INDUCED POLYMORPHS IN BISMUTH,


Corporate Author : WATERVLIET ARSENAL N Y


Personal Author(s) : Davidson,T E ; Lee,A P


Report Date : Nov 1963


Pagination or Media Count : 42


Abstract : It is known from the early work of Bridgman that the two lowest pressure transitions (I-II and IIIII) are accompanied by substantial and abrupt changes in resistivity and volume, the former being highly desirable for pressure calibration purposes. However, unlike the temperature induced allotropic transformations observed in such elements as lithium, cobalt, tin, etc., there is little actually known about many of the characteristics of the pressure induced transitions. This current work involves an examination of the structural and transformation characteristics of the bismuth I-II and II-III transitions under hydrostatic pressures. The relationship of initial structure to the transformation pressure, rate, resistivity change, and resultant structure is discussed. It is shown that the transition pressure and transformation rate are independent of the presence of grain boundaries and associated anisotropy induced deformation. An observed hysteresis in both the I-II and II-III transitions is shown. (Author)


Descriptors :   *BISMUTH , *CRYSTALS , CRYSTAL STRUCTURE , DEFORMATION , TRANSFORMATIONS , HIGH PRESSURE , ANISOTROPY , HYSTERESIS , GRAIN STRUCTURES(METALLURGY) , ELECTRICAL RESISTANCE , CALIBRATION , HYDROSTATIC PRESSURE


Distribution Statement : APPROVED FOR PUBLIC RELEASE