Low cycle fatigue behavior of a directionally solidified nickel base superalloy at elevated temperature
The total strain-controlled low cycle fatigue (LCF) behaviors of a directionally solidified (DS) superalloy at 850℃ and 1000℃ for R=0.05 were investigated.The results of LCF tests indicated that mean stress relaxation occurred under asymmetric straining.The rate of mean stress relaxation increased with the increasing of strain amplitude.The alloy showed cyclic steady at 850℃, while the alloy showed cyclic steady at high strain amplitudes and initial cyclic hardening at low amplitudes at 1000℃.The cyclic stress response of the alloy is closely related with testing temperature and total strain amplitude.All the LCF data obtain under various ratis were well correlated by a modified SWT approach for lifetime prediction, the all data fell into the factor of±3 times scatter band.The SEM results show that the fatigue crac ks of the alloy originate from the subsurface of the specimen at the strain amplitude of 0.475% for 850℃, while from the surface of the specimen at the strain amplitude of 0.404% for 1000℃.
DS superalloy low cycle fatigue strain ratio mean stress relaxation
Shichao Zhang Huichen Yu
Aviation Key Laboratory of Science and Technology on Materials Testing and Evaluation, Science and Technology on Advanced High Temperature Structural Materials Laboratory, Beijing Key Laboratory of Aeronautical Materials Testing and Evaluation, Beijing Institute of Aeronautical Materials, Beijing 100095, China
国际会议
长沙
英文
165-171
2016-10-16（万方平台首次上网日期，不代表论文的发表时间）