Hydrogen embrittlement of a metastable ?-titanium alloy

Localized tensile strain distribution and metallurgy of electron beam welded Ti–5Al–5V–5Mo–3Cr titanium alloys

“…A few possibilities have been proposed for the low ductility in welded metastable ␤ titanium alloys including phase transformation, formation of hard and brittle precipitates, and formation of hydrides at the weld zones. Alvarez et al (2004) showed that hydrogen in excess of 3.5 at% in bulk metastable B-C Ti caused brittle fracture to occur in the aged condition. Danielson et al (2003) found that oxygen embrittled commercially pure Ti by inducing a phase change from low temperature ␣ cells and large ␤ grains in a low oxygen specimen to an acicular microstructure with retained ␤ phase between ␣ cells, Widmanstätten plates, and ␤ phase along grain boundaries.…”

Stress corrosion cracking (SCC) and hydrogen-assisted cracking in titanium alloys

“…At a critical hydrogen concentration the a phase transforms to body centred tetragonal (bct) hydrides, and to d-hydrides on further increase in hydrogen concentration in the matrix (Alvarez et al, 2004). This transformation was stress-induced as it was observed only in front of crack tips.…”

ESR Refining Potential for Titanium Alloys using a CaF2‐based Active Slag

“…Alvarez et al [18] have proved a considerable decrease of the ductility of pure titanium for hydrogen contents above 3.5 at.-%. Chen et al [19] have also shown that in pure titanium which was equilibrated at 400°C already at 77 ppm c-titanium-hydrides and at 350 ppm d-titanium-hydrides occur.…”