Corrosion Cracking of Metallic Materials
Technical rept. Oct 1969-Oct 1970
OHIO STATE UNIV COLUMBUS DEPT OF METALLURGICAL ENGINEERING
Pagination or Media Count:
Activation energies of 6-7 kcal for stress corrosion cracking were determined for unalloyed titanium and titanium alloys Ti-6-4 and Ti-8-1-1, and beta III in CH3OH HCl H2O and CH3OH Br2 solutions, suggesting that either chloride ion attack or titanium hydride formation describe the cracking mechanism. Chemical methods, to reduce the water content of methanol to low levels and to accurately determine these levels, have been developed to examine the effect of small water concentrations on the stress corrosion cracking behavior of titanium in methanol environments. Work on the fundamental aspects of stress corrosion cracking of high-strength steels includes studies of effects of structure on crack velocity, hydrogen interactions with the steel, acoustical emission, dissolution of iron carbides, and growth kinetics of passive films. Studies on hydrogen absorption show that the kinetics of hydrogen entry depended critically on the potential as it relates to the chemical identity of arsenic-containing species. Growth kinetics of passive films at pH 4 and 6 are reported and optical constants are found to exhibit wider variations at these pHs than at pH 8. The dissolution of the film was shown to increase with decreasing pH. Work on the delayed failure of high-strength steels shows that ductility is significantly affected by specimen size, hydrogen charging conditions, and extent of prior deformation.
- Properties of Metals and Alloys