Accession Number : AD0726710

Title :   A Chemical Interpretation of Static Fatigue.

Descriptive Note : Technical rept.,

Corporate Author : NATIONAL BUREAU OF STANDARDS WASHINGTON D C

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

Report Date : JUN 1971

Pagination or Media Count : 37

Abstract : The effect of crack tip environment on the fracture process in glass is discussed. It is suggested that the crack tip environment is determined by local chemical reactions between the crack surface and water at the crack tip. Crack extension is believed to be controlled by the crack tip hydroxyl ion concentration. Experimental support for these ideas is presented. Crack velocity data are consistent with an equation derived from the absolute rate theory of chemical reactions. The hydroxyl ion concentrations of ground glass water slurries are found to correlate with the velocity of crack motion in glass. Furthermore, the apparent activation energy for glass corrosion is found to be in reasonable agreement with that calculated from crack velocity and pH data. Experimental results are consistent with the suggestion that static fatigue is a stress corrosion process in which hydroxyl ions play an important role. (Author)

Descriptors :   (*GLASS, FRACTURE(MECHANICS)), (*CRACK PROPAGATION, CHEMICAL REACTIONS), FATIGUE(MECHANICS), HYDROXIDES, IONS, REACTION KINETICS, STRESS CORROSION

Subject Categories : Physical Chemistry
      Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE