Effect of cooling rate during quenching on the microstructure and creep property of nickel-based superalloy FGH96

• Published in: International journal of minerals, metallurgy and materials Vol. 26; no. 4; pp. 493 - 499
• Main Authors: Feng, Ye-fei, Zhou, Xiao-ming, Zou, Jin-wen, Tian, Gao-feng
• Format: Journal Article
• Language: English
• Published: Beijing University of Science and Technology Beijing 01.04.2019; Springer Nature B.V; Science and Technology on Advanced High Temperature Structural Materials Laboratory, Beijing Institute of Aeronautical Materials, Beijing 100095, China
• Subjects: Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Composites; Cooling; Cooling effects; Cooling rate; Corrosion and Coatings; Creep rate; Creep tests; Deformation mechanisms; Dislocation density; Glass; Heat treating; Load distribution; Materials Science; Metallic Materials; Microstructure; Natural Materials; Nickel; Nickel base alloys; Precipitates; Quenching; Stacking faults; Superalloys; Surfaces and Interfaces; Thin Films; Tribology; cooling rate; secondary γ′ precipitates; quantitative relationship; deformation mechanism; steady creep rate; secondaryγ' precipitates
• ISSN: 1674-4799; 1869-103X
• DOI: 10.1007/s12613-019-1756-2

The effect of cooling rate during quenching on the microstructure and creep property of nickel-based superalloy FGH96 was investigated. Three groups of samples were quenched continuously with three fixed cooling rates, respectively, then subjected to a creep test under a constant load of 690 MPa at 700°C. Clear differences in size of secondary γ′ precipitates, creep properties and substructure of creep-tested samples were observed. The quantitative relationship among cooling rate, the size of secondary γ′ precipitates, and steady creep rate was constructed. It was found that with increasing cooling rate, the size of secondary γ′ precipitates decreases gradually, showing that the relationship between the size of secondary γ′ precipitates and the cooling rate obeys a power law, with an exponent of about −0.6, and the creep rate of steady state follows a good parabola relationship with cooling γ′ precipitate size. For 235°C/min, FGH96 alloy exhibited very small steady creep rate. The density of dislocation was low, and the isolated stacking fault was the dominant deformation mechanism. With decreasing cooling rates, the density of dislocation increased remarkably, and deformation microtwinning was the dominant deformation process. Detailed mechanisms for different cooling rate were discussed.