Creep Behavior of a Re-Free Nickel-Based Single Crystal Superalloy at High Temperature
Creep Behavior of a Re-Free Nickel-Based Single Crystal Superalloy at High Temperature
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DOI：
10.4028/www.scientific.net/msf.788.466
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发表时间：
2014-04
期刊：
影响因子：
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通讯作者：
S. Liang;S. Tian;Z. Guo;Y. Xue;De-long Shu
中科院分区：
文献类型：
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作者：
S. Liang;S. Tian;Z. Guo;Y. Xue;De-long Shu
通过蠕变性能测试和显微组织观察，研究了一种无Re-free单晶镍基高温合金的高温蠕变行为。实验结果表明，该合金在1040℃/137 MPa试验条件下的蠕变寿命为556h。蠕变初期，合金的变形机制为γ基体内部位错滑移，合金中的γ′相沿垂直于应力轴方向转变为筏状组织。在蠕变后期，主/次滑移位错的交替激活可使片状γ′相发生扭曲，促进裂纹沿γ′/γ相界面的萌生和扩展直至蠕变断裂。在试样的不同区域出现了不同形态的筏形γ′相，其中靠近断口区域的筏形γ′相的粗化和扭转可能是由于较大的塑性变形所致。
The creep behavior of a Re-free single crystal Ni-base superalloy at high temperature has been investigated by means of creep property measurement and microstructure observation. The experimental results show that the creep life of the alloy under the testing condition of 1040 oC/137 MPa was measured to be 556h. In the primary stage of creep, the deformation mechanism of the alloy is dislocations slipping within the γ matrix, and the γ′ phase in the alloy is transformed into the rafted structure along the direction vertical to the stress axis. In the latter stage of creep, the alternate activation of the main/secondary slipping dislocations may twist the rafted γ′ phase to promote the initiation and propagation of the cracks along the interfaces of γ′/γ phases up to the creep fracture. And the various configurations of the rafted γ′ phase appeared in the different regions of the sample, thereinto, the coarsening and twisting of the rafted γ′ phase in the regions near the fracture may be attributed to the bigger plastic deformation.