Design and thermomechanical properties of a γ′ precipitate-strengthened Ni-based superalloy with high entropy γ matrix

JOURNAL OF ALLOYS AND COMPOUNDS

卷:792

Article

Detrois, Martin^1,2  Jablonski, Paul D.¹  Antonov, Stoichko^3,4  Li, Shilei^3,5  Ren, Yang⁶  Tin, Sammy⁴  Hawk, Jeffrey A.¹ 

[1] Natl Energy Technol Lab, 1450 Queen Ave SW, Albany, OR 97321 USA

[2] Leidos Res Support Team, 626 Cochrans Mill Rd,POB 10940, Pittsburgh, PA 15236 USA

[3] Univ Sci & Technol Beijing, State Key Lab Adv Met & Mat, Beijing 100083, Peoples R China

[4] IIT, 10 W 32nd St, Chicago, IL 60616 USA

[5] Argonne Natl Lab, Appl Mat Div, 9700 Cass Ave, Lemont, IL 60439 USA

[6] Argonne Natl Lab, Adv Photon Source, Xray Sci Div, 9700 Cass Ave, Lemont, IL 60439 USA

关键词: Nickel-based superalloy;    High-entropy alloy;    Precipitation;    Phase stability;    Mechanical properties;   

DOI  :  10.1016/j.jallcom.2019.04.054

来源: Elsevier

【 摘 要 】

A novel Ni-based superalloy was designed with gamma' precipitate strengthening, controlled gamma/gamma' lattice misfit and high configurational entropy of the gamma matrix for improved high temperature performance up to 800 degrees C. The alloy contains nano-sized gamma' precipitates, MC and other grain boundary carbides. Three variants of the alloy were fabricated using vacuum induction melting, a computational-based homogenization cycle for reducing solidification segregation, and thermomechanical processing steps of forging followed by hot rolling to produce plates from which ASTM standard test specimens were extracted. Tensile testing at room temperature and elevated temperatures up to 800 degrees C revealed superior yield stress when compared to Nimonic 105 with good tensile strength values. Furthermore, the three alloys are machinable with maximum stresses comparable to standard practices as determined using deformation mechanisms maps obtained from Gleeble testing and EBSD analysis. Due to the composition of the experimental alloys falling outside the typical range used to populate thermodynamic databases, differences in phase predictions and related temperatures were observed between the experiment and Thermo-Calc predictions. The gamma' forming elements Ti and Nb had a similar effect on the gamma' precipitates and indirectly contributed to changing the entropy of the gamma matrix. Based on the results of this study, these alloys have the potential for use at 800 degrees C in energy structural applications. Definitions related to this novel class of alloys are discussed. (C) 2019 Elsevier B.V. All rights reserved.

【 授权许可】

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