2022/01/05 by Qing Tan, Tan, Qing, Zhiran Yan +9
Materials Science · #Nuclear Materials and Properties #Hydrogen embrittlement and corrosion behaviors in metals #Fusion materials and technologies
paper · pdf · doi:10.48550/arxiv.2201.01569
The corrosion potential of commercially pure titanium in NaCl solutions is dramatically affected by trace Fe additions, which cause the appearance of submicron pockets of \beta phase at grain boundary triple points. Furthermore, the low solubility of hydrogen in hexagonal close-packed α-Ti makes titanium alloys prone to subsequent hydride-associated failures due to stress corrosion cracking. We analyzed α-α and α-\beta sections of the abutting grain boundary of a \beta pocket in a Grade 2 CP-Ti, and the α-\beta phase boundary. Fe and H partition to \beta and segregate at the grain boundary, but no segregation is seen at the α-\beta phase boundary. In contrast, a significant Ni (>1 at%) accumulation is observed at the α-\beta phase boundary. We propose that the \beta-pockets act as hydrogen traps and facilitate the nucleation and growth of hydrides along grain boundaries in CP-Ti.