Xu H, Zhang Z J, Zhang P, Cui C Y, Jin T, Zhang Z F
Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, 110016, Shenyang, PR China.
University of Chinese Academy of Sciences, 19A Yuquan Road, 100049, Beijing, PR China.
Sci Rep. 2017 Aug 14;7(1):8046. doi: 10.1038/s41598-017-07884-4.
It is a great challenge to improve the strength of disc superalloys without great loss of plasticity together since the microstructures benefiting the strength always do not avail the plasticity. Interestingly, this study shows that the trade-off relationship between strength and plasticity can be broken through decreasing stacking fault energy (SFE) in newly developed Ni-Co based disc superalloys. Axial tensile tests in the temperature range of 25 to 725 °C were carried out in these alloys with Co content ranging from 5% to 23% (wt.%). It is found that the ultimate tensile strength (UTS) and uniform elongation (UE) are improved synchronously when microtwinning is activated by decreasing the SFE at 650 and 725 °C. In contrast, only UTS is improved when stacking fault (SF) dominates the plastic deformation at 25 and 400 °C. These results may be helpful for designing advanced disc superalloys with relatively excellent strength and plasticity simultaneously.
在不造成塑性大幅损失的情况下提高盘式高温合金的强度是一项巨大挑战，因为有利于强度的微观结构往往对塑性不利。有趣的是，这项研究表明，在新开发的镍钴基盘式高温合金中，通过降低层错能（SFE）可以打破强度与塑性之间的权衡关系。对钴含量在5%至23%（重量百分比）范围内的这些合金进行了25至725°C温度范围内的轴向拉伸试验。结果发现，在650和725°C下通过降低SFE激活微孪晶时，极限抗拉强度（UTS）和均匀伸长率（UE）会同步提高。相比之下，在25和400°C下当层错（SF）主导塑性变形时，只有UTS会提高。这些结果可能有助于设计同时具有相对优异强度和塑性的先进盘式高温合金。
