Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7972321 | Materials Science and Engineering: A | 2018 | 24 Pages |
Abstract
High W-content cast Ni-based superalloy which can be served as isothermal forging die materials over 1050â¯Â°C was investigated in this paper. Based on the microstructure evolutions, stress-rupture life of the alloy were examined under 1100â¯Â°C /70â¯MPa, where the alloy was evaluated after thermally exposed at 1000, 1050, and 1100â¯Â°C for 100-1000â¯h, respectively. Results showed that increasing of exposure temperature can cause coarsening and coalescing of γⲠprecipitates along with a decreasing in their volume fraction, especially at 1100â¯Â°C. The coarsening rate of the γⲠprecipitates increased with the exposure temperature and followed by the modified Lifshitz-Slyozov-Wagner coarsening theory of Ostwald ripening. The coarsening rate coefficient (k) at 1000, 1050, and 1100â¯Â°C was calculated to be 5.72, 7.40, and 8.71â¯nm/s1/3, respectively. In addition, at those temperatures, it found the blocky M6C carbides in the interdendritic area to be precipitated and coarsened. Furthermore, the M6C carbides linked with each other like a chain wrapped around the grain boundary and along the eutectic γⲠphase. Because of the degradation of the microstructure, the stress-rupture life decreased after thermal exposure, from 94.8â¯h at 1000â¯Â°C to 49.3â¯h at 1100â¯Â°C for 1000â¯h. Finally, in view of the experimental results, a relationship between the microstructural evolution and the stress-rupture life of the alloy was discussed in details.
Related Topics
Physical Sciences and Engineering
Materials Science
Materials Science (General)
Authors
Tongjin Zhou, Hongsheng Ding, Xiuping Ma, Wei Feng, Huibin Zhao, Yu Meng, Huaxia Zhang, Yongmin Lv,