Primary creep in single crystal superalloys: some comments on effects of composition and microstructure
Primary creep in single crystal superalloys: some comments on effects of composition and microstructure
复制标题
DOI：
10.1179/174328408x369311
复制
发表时间：
2009-02-01
影响因子：
1.8
通讯作者：
Zhang, L.
中科院分区：
文献类型：
--
作者：
Rae, C. M. F.;Zhang, L.
当前单晶高温合金的低温蠕变特征是：一次蠕变应变较大，但与取向有关，其次是长时间的二次蠕变，其速率与一次蠕变应变密切相关。叙述了合金的孕育、成核和扩展过程，并讨论了合金成分和显微组织对这些过程的影响。结果表明，蠕变的孕育期对合金成分不敏感，但改变γ′尺寸的热处理对蠕变的早期阶段有较大的影响。高初蠕变的关键似乎是位错带形核的迁移率，这对合金成分很敏感。伽玛和伽玛'中的断层能量对于确定位错带的形式很重要。早期的结果表明，钌可能对降低第四代合金的初蠕变有有益的作用。
Creep at low temperatures in current single crystal superalloys is characterised by a large but orientation dependent primary creep strain followed by prolonged secondary creep at a rate closely linked to the primary creep strain. The processes of incubation, nucleation and propagation are described and the linked effects of alloy composition and microstructure are discussed in relation to these processes. It is shown that the incubation period is relatively insensitive to the alloy composition but that heat treatments which vary the gamma' size can have a larger effect on the early stages of creep. The key to high primary creep appears to be the mobility of the dislocation ribbons nucleated and this is sensitive to the alloy composition. Fault energies in both the gamma and the gamma' are important in determining the form of the dislocation ribbons. Early results suggest that ruthenium may have a beneficial effect reducing the primary creep of fourth generation alloys.