Microstructural evolution and castability prediction in newly designed modern third-generation nickel-based superalloys
来源期刊：International Journal of Minerals Metallurgy and Materials2016年第5期
论文作者：Homam Naffakh-Moosavy
文章页码：548 - 562
摘 要：The present research aims to establish a quantitative relation between microstructure and chemical composition（i.e., Ti, Al, and Nb） of newly designed nickel-based superalloys. This research attempts to identify an optimum microstructure at which the minimum quantities of γ/γ′ and γ/γ″ compounds are achieved and the best castability is predicted. The results demonstrate that the highest quantity of intermetallic eutectics（i.e., 41.5wt%） is formed at 9.8wt%（Ti + Al）. A significant quantity of intermetallics formed in superalloy 1（with a composition of γ- 9.8wt%（Ti + Al））, which can deteriorate its castability. The type and morphology of the eutectics changed and the amount considerably decreased with decreasing Ti + Al content in superalloy 2（with a composition of γ- 7.6wt%（Ti + Al）, 1.5wt% Nb）. Thus, it is predicted that the castability would improve for superalloy 2. The same trend was observed for superalloy 4（with a composition of γ- 3.7wt%（Ti + Al）, 4.4wt% Nb）. This means that the amount of Laves increases with increasing Nb（to 4.4wt%） and decreasing Ti + Al（to 3.7wt%） in superalloy 4. The best castability was predicted for superalloy 3（with a composition of γ- 5.7wt%（Ti + Al）, 2.8wt% Nb）.
Homam Naffakh-Moosavy
Department of Materials Engineering, Faculty of Engineering, Tarbiat Modares University
摘 要：The present research aims to establish a quantitative relation between microstructure and chemical composition（i.e., Ti, Al, and Nb） of newly designed nickel-based superalloys. This research attempts to identify an optimum microstructure at which the minimum quantities of γ/γ′ and γ/γ″ compounds are achieved and the best castability is predicted. The results demonstrate that the highest quantity of intermetallic eutectics（i.e., 41.5wt%） is formed at 9.8wt%（Ti + Al）. A significant quantity of intermetallics formed in superalloy 1（with a composition of γ- 9.8wt%（Ti + Al））, which can deteriorate its castability. The type and morphology of the eutectics changed and the amount considerably decreased with decreasing Ti + Al content in superalloy 2（with a composition of γ- 7.6wt%（Ti + Al）, 1.5wt% Nb）. Thus, it is predicted that the castability would improve for superalloy 2. The same trend was observed for superalloy 4（with a composition of γ- 3.7wt%（Ti + Al）, 4.4wt% Nb）. This means that the amount of Laves increases with increasing Nb（to 4.4wt%） and decreasing Ti + Al（to 3.7wt%） in superalloy 4. The best castability was predicted for superalloy 3（with a composition of γ- 5.7wt%（Ti + Al）, 2.8wt% Nb）.
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