GH4033合金短时超温后的显微组织损伤及力学性能MICROSTRUCTURAL DEGRADATION AND MECHANICAL PROPERTIES OF GH4033 ALLOY AFTER OVERHEATING FOR SHORT TIME

对已服役的航空发动机用GH4033合金二级涡轮叶片榫头部位进行900~1100 ℃短时超温3 min热处理, 之后再进行组织表征和力学性能测试, 研究了合金短时超温过程中的组织损伤及其对室温硬度和700 ℃, 430 MPa 下持久寿命的影响规律. 结果表明, GH4033合金中γ′相颗粒在短时超温过程中发生粗化和回溶现象, 当温度达到980 ℃及以上时, 保温 3 min后γ′相完全回溶; 随着超温温度的升高, 晶界碳化物逐渐溶解, 1100 ℃时完全溶解, 并造成晶粒开始长大. 短时超温后叶片合金的室温硬度随着γ′相的回溶急剧下降, 当γ′相完全回溶时室温硬度降低至 170 HV 左右. 合金在700 ℃, 430 MPa 下持久寿命随着短时超温温度的升高呈现先增大后急剧降低的规律, 其主要受γ′相的回溶与再析出以及晶界碳化物回溶的影响.

Service safety of turbine blades in aircraft engines are threatened by microstructural and property degradation instantly caused by overheating during service. Systematic investigations about microstructural degradation during overheating exposures and its influence on mechanical properties of turbine blades during service are limitedly reported. In this work, microstructure and mechanical properties of GH4033 alloy, which was sectioned from the shank of a serviced 2nd stage turbine blade in an aircraft engine, were studied after overheating at 900~1100 ℃ for 3 min. Microstructural degradation during overheating exposures as well as its influence on room temperature hardness and stress rupture life at 700 ℃, 430 MPa were analyzed. The results of microstructural characterization indicated that the coarsening and dissolution of γ′ precipitates were introduced by overheating exposures, and all of the γ′ precipitates dissolved at 980 ℃ for 3 min. Gradual dissolution of grain boundary (GB) carbides was observed with the increase of overheating temperature. Complete dissolution of GB carbides at 1100 ℃ resulted in grain growth. The room temperature hardness after overheating exposures decreased grossly with the dissolution of γ′ phase. Due to the dissolution and re-precipitation of γ′ phase as well as the dissolution of GB carbides, the stress rupture life under 700 ℃, 430 MPa of GH4033 alloy was initially increased and then decreased significantly.

全文下载：http://pan.baidu.com/s/1dD56MRn