期刊
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
卷 43A, 期 2, 页码 491-504出版社
SPRINGER
DOI: 10.1007/s11661-011-0877-7
关键词
-
资金
- United States Department of Energy (US DOE), Nuclear Energy University [DE-AC07-051D141517, 00090711]
The fatigue crack propagation (FCP) as well as the sustained loading crack growth (SLCG) behavior of two solid-solution-strengthened Ni-based superalloys, INCONEL 617 (Special Metals Corporation Family of Companies) and HAYNES 230 (Haynes International, Inc., Kokomo, IN), were studied at increased temperatures in laboratory air under a constant stress-intensity-factor (K) condition. The crack propagation tests were conducted using a baseline cyclic triangular waveform with a frequency of 1/3 Hz. Various hold times were imposed at the maximum load of a fatigue cycle to study the hold time effect. The results show that a linear elastic fracture mechanics (LEFM) parameter, stress intensity factor (K), is sufficient to describe the FCP and SLCG behavior at the testing temperatures ranging from 873 K to 1073 K (600 A degrees C to 800 A degrees C). As observed in the precipitation-strengthened superalloys, both INCONEL 617 and HAYNES 230 exhibited the time-dependent FCP, steady SLCG behavior, and existence of a damage zone ahead of crack tip. A thermodynamic equation was adapted to correlate the SLCG rates to determine thermal activation energy. The fracture modes associated with crack propagation behavior were discussed, and the mechanism of time-dependent FCP as well as SLCG was identified. Compared with INCONEL 617, the lower crack propagation rates of HAYNES 230 under the time-dependent condition were ascribed to the different fracture mode and the presence of numerous W-rich M6C-type and Cr-rich M23C6-type carbides. Toward the end, a phenomenological model was employed to correlate the FCP rates at cycle/time-dependent FCP domain. All the results suggest that an environmental factor, the stress assisted grain boundary oxygen embrittlement (SAGBOE) mechanism, is mainly responsible for the accelerated time-dependent FCP rates of INCONEL 617 and HAYNES 230.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据