Development of low-density γ/γ′ Co-Al-Ta-based superalloys with high solvus temperature
Development of low-density γ/γ′ Co-Al-Ta-based superalloys with high solvus temperature
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DOI：
10.1016/j.actamat.2020.02.049
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发表时间：
2020-04-15
期刊：
影响因子：
9.4
通讯作者：
Liu, Xingjun
中科院分区：
文献类型：
--
作者：
Chen, Yuechao;Wang, Cuiping;Liu, Xingjun
本文报道了不含 W、Mo、V 以及含 Ni 和 Cr 的 Co-Al-Ta 基高温合金的开发。特别是，通过实验验证了 Co-12Al-2Ta 合金中亚稳态 L1(2)-gamma' 相的存在。结果表明，通过提高所研究合金中的Ni含量，可以提高γ相稳定性并拓宽γ/γ'成分范围。此外，元素分配证明Cr是γ相形成体，其添加减少了γ/γ'晶格失配和y沉淀物粗化率。此外，所开发的含Cr合金即使在800-1100℃的高温下也表现出优异的γ相稳定性。特别是Co-30Ni-12Al-4Ta-12Cr（12Cr）合金具有高固溶线温度（类似于1152℃）、低密度（类似于8.38 g/cm(3)）、低gamma/gamma'晶格失配（类似于至+0.33%），并且γ'沉淀物的粗化率低（类似于900℃时的1.95 x 10(27) m/s）。此外，所开发的12Cr合金在环境温度和高温下的标称和比屈服强度值并不比其他可用的含Cr和无W钴基高温合金差。 (C) 2020 Acta Materialia Inc. 由 Elsevier Ltd 出版。保留所有权利。
The present paper reports the development of W-, Mo-, and V-free and Ni- and Cr-containing Co-Al-Ta-based superalloys. In particular, the presence of a metastable L1(2)-gamma' phase is experimentally verified in Co-12Al-2Ta alloy. The results show that the gamma phase stability is improved and the gamma/gamma' composition range is broadened by rising the Ni content in alloys under study. Moreover, elemental partitioning proves that Cr was a gamma-phase former, which addition reduces the gamma/gamma' lattice misfit and the y precipitate coarsening rate. Moreover, the developed Cr-containing alloys exhibit excellent gamma phase stability even at high temperatures of 800-1100 degrees C. In particular, Co-30Ni-12Al-4Ta-12Cr (12Cr) alloy possesses a good combination of high solvus temperature (similar to 1152 degrees C), low density (similar to 8.38 g/cm(3)), low gamma/gamma' lattice misfit (similar to+0.33%), and low coarsening rate of gamma' precipitate (similar to 1.95 x 10(27) m/s at 900 degrees C). Besides, nominal and specific yield strength values of the developed 12Cr alloy at ambient and high temperatures are no worse than those of other available Cr-containing and W-free cobalt-based superalloys. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.