Notch effects on high-cycle fatigue properties of Ti–6Al–4V ELI alloy at cryogenic temperatures Original Research Article

Notch effects on the high-cycle fatigue properties of the forged Ti–6Al–4V ELI alloy at cryogenic temperatures were investigated. Also, the high-cycle fatigue data were compared with the rolled Ti–5Al–2.5Sn ELI alloy. The one million cycles fatigue strength (FS) of the smooth specimen for the forged Ti–6Al–4V ELI alloy increased with a decrease of test temperature. However, the FS of each notched specimen at 4 K were lower than those at 77 K. On the other hand, the FS of the smooth and the notched specimens for the forged Ti–6Al–4V ELI alloy at 4 K were lower than those for the rolled Ti–5Al–2.5Sn ELI alloy. This is considered to be the early initiation of the fatigue crack in the forged Ti–6Al–4V ELI alloy compares with the forged Ti–5Al–2.5Sn ELI.