The effect of internal hydrogen on the stress corrosion cracking of Ti-6Al-6V-2Sn in 3.5% NaCl solution

• Published in: Materials science and engineering 1980-08, Vol.45 (1), p.49-54
• Main Authors: Lederich, R.J., Sastry, S.M.L., Pao, P.S.
• Format: Article
• Language: English
• ISSN: 0025-5416
• DOI: 10.1016/0025-5416(80)90068-3

The microstructural dependence of the effects of internal and external hydrogen on subcritical sustained-load cracking behavior in Ti-6Al-6V-2Sn was studied in specimens which had been β annealed, recrystallization annealed or solution treated and aged with internal hydrogen concentrations from 10 to 600 ppm. The threshold stress intensity and crack growth rates were determined in dry argon and 3.5% NaCl solution, and the fracture morphology was studied by scanning electron microscopy. The threshold stress intensities were lower and the crack growth rates were higher in 3.5% NaCl solution than in dry argon. The alloy which had been solution treated and aged exhibited a lower threshold stress intensity and higher crack growth rates than did the β-annealed and recrystallization-annealed alloys. An increased hydrogen concentration resulted in an enhanced cleavage, a lower threshold stress intensity and an accelerated crack growth in 3.5% NaCl solution for all three microstructures. The effects of internal and external hydrogen on the sub-critical crack growth were additive.