Stress Corrosion Cracking off Ti and Zr in HCl-Methanol Solutions

Abstract

Abstract It was discovered by the authors that Ti is easily attacked by stress corrosion cracking in methanol containing HCl. This is a report on a study to assess quantitatively stress corrosion cracking of Ti in alcohol solutions. At the same time stress corrosion cracking of Zr was studied because of its similarity in chemical behavior to Ti. Stress corrosion cracking of Ti occurs in methanol solutions containing HCl or H2SO4 and that of Zr is observed in methanol containing HCl or H2SO4 or HCOOH and in ethanol containing HCl. In HCl-alcohol solutions it is observed also that the larger the molecular weight of the alcohol, the longer life the metals have. Addition of water to HCl-methanol solution prevents stress corrosion cracking of Ti and Zr. Critical concentration of water in 0.4 percent HCl-methanol solution is about 1.5 percent for Ti and about 3 percent for Zr. To prevent stress corrosion cracking by stress relief, annealing temperatures should be higher than 500 C (932 F) for Ti and 450 C (842 F) for Zr.