TY - GEN
T1 - Effects of environments and shot peening on creep and creep-fatigue behaviors of Ni-Fe-base superalloy inconel® alloy 706
AU - Yoshioka, Yomei
AU - Saito, Daizo
AU - Sumiya, Rie
AU - Ishibashi, Kazutoshi
AU - Ito, Shoko
AU - Kobayashi, Daisuke
AU - Itou, Akihiro
AU - Miyabe, Masamichi
AU - Kagiya, Yukio
PY - 2012
Y1 - 2012
N2 - Fleet leader machines with non-shot-peened discs made of Inonel® alloy 706 were experienced to have cracks in the first stage gas turbine wheels. These were inter-granular cracking and observed to be highly stressed locations with less potential for oxidation, which is thought to be quasi-brittle inter-granular cracking due to stress induced atmospheric oxygen penetration, so called, hold-time cracking. To recognize this phenomenon, creep and creep-fatigue tests with smooth and notched specimens were conducted at 600 and 650°C in air and vacuum and confirmed the environmental effects on those lives and fracture modes. The effectiveness of shot peening which was used as one of the countermeasures for this phenomenon was verified by using the creep-fatigue tests. The durability was also evaluated by thermal and stress aging tests at 450 and 500°C up to around 104 hours. Little relaxations were observed during the thermal agings after the initial rapid relaxation of the surface residual stress, but the effects of the loading stresses were observed above the yielding stress at each temperature.
AB - Fleet leader machines with non-shot-peened discs made of Inonel® alloy 706 were experienced to have cracks in the first stage gas turbine wheels. These were inter-granular cracking and observed to be highly stressed locations with less potential for oxidation, which is thought to be quasi-brittle inter-granular cracking due to stress induced atmospheric oxygen penetration, so called, hold-time cracking. To recognize this phenomenon, creep and creep-fatigue tests with smooth and notched specimens were conducted at 600 and 650°C in air and vacuum and confirmed the environmental effects on those lives and fracture modes. The effectiveness of shot peening which was used as one of the countermeasures for this phenomenon was verified by using the creep-fatigue tests. The durability was also evaluated by thermal and stress aging tests at 450 and 500°C up to around 104 hours. Little relaxations were observed during the thermal agings after the initial rapid relaxation of the surface residual stress, but the effects of the loading stresses were observed above the yielding stress at each temperature.
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U2 - 10.1115/GT2012-68313
DO - 10.1115/GT2012-68313
M3 - Conference contribution
AN - SCOPUS:84881179960
SN - 9780791844717
T3 - Proceedings of the ASME Turbo Expo
SP - 91
EP - 98
BT - ASME Turbo Expo 2012
T2 - ASME Turbo Expo 2012: Turbine Technical Conference and Exposition, GT 2012
Y2 - 11 June 2012 through 15 June 2012
ER -