Accession Number:

AD0643598

Title:

PERCUSSIVE (SHOCK) COMPRESSION OF QUARTZ,

Descriptive Note:

Corporate Author:

FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO

Report Date:

1966-12-07

Pagination or Media Count:

21.0

Abstract:

There is a large amount of silica in the earths crust, which appears to be the main rock-forming material. Due to the fact that the high compressibility of silica at various depths may influence phenomena taking place underground high polymorphic conversions, the study of silica conversion involving dense forms at a high temperature and pressure was made. In 1953, a crystalline form of silica--coesite with a density of 3.01 gcu cm was discovered, obtained by a static pressure of 35,000 kgm at temperatures from 500-800C. Coesite was found to come directly from quartz without using mineralizers it was found in three large meteorite craters with a probable percussive origin. There arose the necessity to prove that coesite is formed in a very short action time under high pressure and temperature. Quartz crystals were cut at various angles and subjected to different types of compression shock waves. Screens of aluminum and iron were prepared to measure the shock waves. The waves were created by reflecting various detonation eaves from the screens and by percussion of aluminum and iron flakes accelerated by explosion products. Samples with a width to height ratio of more than three were used in all experiments. Time intervals were taken by an electrocontact method and four oscillograms. Many equations are given with the application of the Hook Law. One of the conclusions is that displacing stresses within the body can be disregarded in comparison to normal stresses. Here the material is investigated as a liquid. An elastic and a plastic wave are produced, which react a certain way and then act as one. Author

Subject Categories:

  • Geology, Geochemistry and Mineralogy
  • Ceramics, Refractories and Glass
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE