Achieving Exceptional Strength-Ductility Synergy via Nano-precipitation Hardening in a Ni–Fe–Cr–Co–Al Alloy

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Vol. 55; no. 7; pp. 2359 - 2373
• Main Authors: Kar, Shubhada, Shivam, Vikas, Srivastava, V. C., Mandal, G. K.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-07-2024; Springer Nature B.V
• Subjects: Alloys; Aluminum; Annealing; Characterization and Evaluation of Materials; Chemistry and Materials Science; Chromium; Cobalt; Ductility; High entropy alloys; High temperature; Iron; Materials Science; Mechanical properties; Metallic Materials; Nanotechnology; Nickel base alloys; Original Research Article; Precipitation hardening; Recrystallization; Room temperature; Solid solutions; Solution strengthening; Structural Materials; Superalloys; Surfaces and Interfaces; Thin Films; Vacuum induction melting
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-024-07402-y

In the present work, a Ni–Fe–Co–Cr–Al-based medium entropy alloy (MEA) was developed by exploring the vast compositional space provided by the birth of high-entropy alloys (HEAs). The composition was designed
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the CALPHAD approach and the designed alloy was melted through the vacuum induction melting (VIM) technique using commercial elements. Post-homogenization treatment, the material was cold deformed up to 73 pct reduction in thickness. This cold-rolled material was annealed with varying duration at a fixed temperature of 900 °C for a better understanding of the static recrystallization mechanism. The systematic static recrystallization study was performed to design a heterogeneous grain distribution within the matrix
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partial recrystallization. Post-establishment of the annealing schedule, ageing treatment at 600 °C for 5 hours was carried out. The room temperature mechanical properties were evaluated for selected ageing conditions. An excellent strength of > 950 MPa accompanied by an appreciable ductility of 60 pct was obtained for the fully recrystallized and aged specimen. The obtained results surpassed the strength-ductility synergy exhibited by various solid solution-strengthened (SS) Ni-based superalloys and heterogeneous HEAs and hold the potential to be explored for elevated temperature applications. A systematic study has also been carried out to estimate the contribution of various strengthening factors in the designed alloy and the predicted results corroborate well with the experimental findings.