Effects of stacking fault energy on the creep behaviors of Ni-base superalloy
Effects of stacking fault energy on the creep behaviors of Ni-base superalloy
复制标题
堆垛层错能对镍基高温合金蠕变行为的影响
DOI：
10.1016/j.matdes.2014.08.007
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发表时间：
2014-12-01
影响因子：
8.4
通讯作者：
Sun, Xiaofeng
中科院分区：
文献类型：
--
作者：
Tian, Chenggang;Han, Guoming;Sun, Xiaofeng
钴含量为23重量%为了研究层错能（SFE）对蠕变机制的影响，用Ni系统地取代了含Co的Ni基高温合金。利用透射电镜（TEM）研究了合金在725 ℃和630 MPa条件下不同蠕变阶段的变形组织。结果表明，合金的蠕变寿命随SFE的降低而提高，这与合金中Co含量的增加相对应。在蠕变初期，位错很难脱离SFE。相反，在第二和第三蠕变阶段，位错在γ/γ '界面处解离，并且部分位错开始剪切γ'沉淀物，在高SFE合金中留下孤立断层（IF），而位错在基体中解离，部分位错扫过基体，γ '沉淀产生扩展堆垛层错（ESF）或变形微孪晶，其参与扩散，介导的低SFE合金中的重新排序。结果表明，随着SFE的降低，变形过程中的微孪晶有利于合金的蠕变抗力的提高，从而改善合金的蠕变性能。(C)2014爱思唯尔有限公司版权所有。
Cobalt in a 23 wt.% Co containing Ni-base superalloys was systematically substituted by Ni in order to study the effects of stacking fault energy (SFE) on the creep mechanisms. The deformation microstructures of the alloys during different creep stages at 725 degrees C and 630 MPa were investigated by transmission electron microscopy (TEM). The results showed that the creep life increased as the SFE decreased corresponding to the increase of Co content in the alloys. At primary creep stage, the dislocation was difficult to dissociate independent of SFE. In contrast, at secondary and tertiary creep stages the dislocations dissociated at gamma/gamma' interface and the partial dislocation started to shear gamma' precipitates, leaving isolated faults (IFs) in high SFE alloy, while the dislocations dissociated in the matrix and the partials swept out the matrix and gamma' precipitates creating extended stacking faults (ESFs) or deformation microtwins which were involved in diffusion-mediated reordering in low SFE alloy. It is suggested that the deformation microtwinning process should be favorable with the decrease of SFE, which could enhance the creep resistance and improve the creep properties of the alloys. (C) 2014 Elsevier Ltd. All rights reserved.