1 Institute for Special Steels, Central Iron and Steel Research Institute, Beijing 100081, China 2 College of Material Science & Engineering, Taiyuan Science & Technology University, Taiyuan 030024, Shanxi, China
Microstructural evolution and mechanical properties of a new Ni-based heat-resistant alloy during aging at 750��C
1 Institute for Special Steels, Central Iron and Steel Research Institute, Beijing 100081, China 2 College of Material Science & Engineering, Taiyuan Science & Technology University, Taiyuan 030024, Shanxi, China
ժҪ Microstructural evolution and mechanical properties of a new candidate Ni-based heat-resistant alloy for advanced ultra-supercritical (A-USC) steam turbine rotors were investigated during aging at 750��C up to 10000 h. The evolutions of �á� particles inside austenitic grain and M23C6 carbides along grain boundaries were characterized according to their morphologies, distributions, and growth kinetics. Mean radius of the �á� spherical particles grew from 20��3 to 90��0 nm after aging for 10000 h, and the corresponding coarsening behavior was conformed to the law of Lifschitz-Slyosovd-Wagner (LSW). The weight fraction of �á� particles slightly increased from 10��0 to 12��0 wt��% after aging of long duration at 750��C. The Cr-rich M23C6 carbides discontinuously precipitated along grain boundaries, while other detrimental phases were not formed during the aging treatment, and hence the strength of grain boundary was enhanced by these discontinuously distributed carbides. The critical size of �á� had a direct influence on the maximum hardness of this alloy. Moreover, this alloy presented a good impact toughness for the safety after long time aging at high temperature.
Abstract��Microstructural evolution and mechanical properties of a new candidate Ni-based heat-resistant alloy for advanced ultra-supercritical (A-USC) steam turbine rotors were investigated during aging at 750��C up to 10000 h. The evolutions of �á� particles inside austenitic grain and M23C6 carbides along grain boundaries were characterized according to their morphologies, distributions, and growth kinetics. Mean radius of the �á� spherical particles grew from 20��3 to 90��0 nm after aging for 10000 h, and the corresponding coarsening behavior was conformed to the law of Lifschitz-Slyosovd-Wagner (LSW). The weight fraction of �á� particles slightly increased from 10��0 to 12��0 wt��% after aging of long duration at 750��C. The Cr-rich M23C6 carbides discontinuously precipitated along grain boundaries, while other detrimental phases were not formed during the aging treatment, and hence the strength of grain boundary was enhanced by these discontinuously distributed carbides. The critical size of �á� had a direct influence on the maximum hardness of this alloy. Moreover, this alloy presented a good impact toughness for the safety after long time aging at high temperature.
��������:High technology research and development programme of china
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E-mail: tian82628@163.com
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Zhong-liang Tian,,Sen-bao Jiang,Zheng-zong Chen,Han-sheng Bao,Zheng-dong Liu,*. Microstructural evolution and mechanical properties of a new Ni-based heat-resistant alloy during aging at 750��C[J]. �й������ڿ���, 2017, 24(5): 513-519.
Zhong-liang Tian,,Sen-bao Jiang,Zheng-zong Chen,Han-sheng Bao,Zheng-dong Liu,*. Microstructural evolution and mechanical properties of a new Ni-based heat-resistant alloy during aging at 750��C. Chinese Journal of Iron and Steel, 2017, 24(5): 513-519.
2017, Vol. 24 
