Initiation and Propagation Behaviours of Naturally Initiated Small Crack in a Polycrystalline Ni-base Superalloy under Thermo-Mechanical Fatigue Condition
Ni-base superalloys used as blade and vane in gas turbine are subjected with thermo-mechanical fatigue (TMF) loading.Therefore, an understanding of the crack propagation characteristics under TMF conditions is essential.In this work, the initiation and propagation behaviours of naturally initiated small crack in a polycrystalline Ni-base superalloy, IN738LC, under the several kinds of TMF conditions.The effect of phase angle between temperature and strain cycles in TMF loading on the initiation and propagation behaviour of small crack was investigated.The experimental results revealed that the initiation and propagation morphologies of the naturally initiated crack were affected by thermo-mechanical loading condition.The small crack growth rate was also affected with the TMF conditions.However, when the small crack propagation rates were correlated with the effective fatigue J integral range based on the continuum fracture mechanics, they could be expressed with a unique curve regardless of the difference in TMF condition.The TMF life could be predicted by the crack propagation life based on the small crack propagation.
Thermo-mechanical fatigue Naturally initiated small crack Phase angle Fatigue J integral Initiation and propagation morphologies
Yasuhiro Yamazaki Tomohiro Tomita
Department of Engineering, Niigata Institute of Technology, Fujihashi 1719, Kashiwazaki 945-1195,Jap Department of Mechanical and control Engineering, Niigata Institute of Technology, Fujihashi 1719,Ka
国际会议
长沙
英文
2-6
2016-10-16（万方平台首次上网日期，不代表论文的发表时间）