Accession Number:

AD0256351

Title:

INFLUENCE OF DISPLACIVE-SHEARING STRESSES ON THE KINETICS OF RECONSTRUCTIVE TRANSFORMATIONS EFFECTED BY PRESSURE IN THE RANGE 0-100,000 BARS

Descriptive Note:

Corporate Author:

PENNSYLVANIA STATE UNIV UNIVERSITY PARK

Personal Author(s):

Report Date:

1960-04-02

Pagination or Media Count:

1.0

Abstract:

Earlier results showed that ordinary laboratory grinders and mixers were able to convert several phases e.g. PbO2, MnF2, CaCO3, BeF2, etc. into their respective high-pressure forms which, at equilibrium require 10-15,000 atmospheres at room temperature. Hence, experiments were devised to attempt to separate the effect of hydrostatic pressure from those of shearing stresses and bond-breakage. A study of the influence of shearing stresses superimposed upon quasihydrostatic pressures of up to 100,000 bars at temperatures below 550 C was made possible by the development of simple apparatus. This consists of the Bridgman uniaxial-type apparatus, with a provision for continuous rotation of the bottom piston very slowly back and forth through a 2 degree arc. The sample is heated externally displacive-shearing runs with pressure and temperature automatically controlled can be made for periods exceeding several days if desired. The results clearly separate the influence of hydrostatic pressure itself upon reaction rates from the effect of the added displacive-shearing stresses. From the results it becomes clear that equilibrium relations between phases are not altered by the shearing stresses. Author

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Distribution Statement:

APPROVED FOR PUBLIC RELEASE