Abstract
To reveal the influence of hydrogen on the characteristics of defect-free titanium alloy welded joints, the effects of hydrogen addition on the precipitation behavior in the hydrogenated 0.12 wt.%H weld zone of Ti-0.3Mo-0.8Ni alloy argon-arc-welded joints have been investigated. The results showed that lamellar δ-hydride (face-centered cubic) could only precipitate from α-lamellae, but not from the transformed β-phase due to the high hydrogen solubility in β-phase. Formation of δ-hydride was the result of the αH-phase separation reaction: αH → α (H-lean region) + δ (H-rich region). The formation mechanism of the relatively massive δ-hydride in the αH-matrix was mainly based on the combined effects of harsh stress field states and stringent hydrogen content requirements. A sharp drop in elongation and a slight increase in weld zone hardness of the hydrogenated welded joint were associated with δ-hydride precipitation.
Original language | English |
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Pages (from-to) | 1902-1907 |
Number of pages | 6 |
Journal | JOM |
Volume | 70 |
Issue number | 9 |
DOIs | |
Publication status | Published - 1 Sept 2018 |
Externally published | Yes |