Effect of nitrogen addition and aging treatment on microstructure and high temperature mechanical properties of Ti‐48Al‐2Cr‐2Nb (at%) intermetallic alloy

•N addition resulted in a significant microstructure refinement in 4822 alloy.•N addition prevented instability of the lamellar structure during aging.•Higher SPT forces were achieved in the N-bearing alloys aged at 700 °C/10 h.•N addition increased uniformity of microstructures and mechanical prope...

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Veröffentlicht in:Journal of alloys and compounds 2022-05, Vol.904, p.164077, Article 164077
Hauptverfasser: Ghorbani, Hamid Reza, Kermanpur, Ahmad, Rezaeian, Ahmad, Sadeghi, Fazlollah, Ahmadi Siahboumi, Abbas
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Sprache:eng
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Zusammenfassung:•N addition resulted in a significant microstructure refinement in 4822 alloy.•N addition prevented instability of the lamellar structure during aging.•Higher SPT forces were achieved in the N-bearing alloys aged at 700 °C/10 h.•N addition increased uniformity of microstructures and mechanical properties.•The 1N alloy exhibited the most uniform deformation behavior during SPT. Effects of nitrogen (N) addition (0.5, 1, and 2 at%) on microstructure formation and high temperature mechanical properties of the age-hardened Ti‐48Al‐2Cr‐2Nb (4822, at%) intermetallic alloy were investigated. Alloys were fabricated by vacuum arc re-melting followed by hot isostatic pressing, solution annealing, and finally aging at two different conditions of 700 °C/10 h or 900 °C/1 h. Mechanical properties of the age-hardened samples were investigated via small punch testing at 800 °C. Results showed that N addition resulted in microstructure refinement and increased uniformity of microstructures and mechanical properties. Lamella coarsening and fragmentation was occurred during both aging conditions; however, a more stable lamellar microstructure was achieved by N addition. Colonies with various lamellar orientation showed different fragmentation behavior. Better mechanical properties was achieved in the alloy containing 1 at%N after aging at 900 °C/1 h. Inter-lamellar fracture was the predominant fracture mechanism in all intermetallic alloys.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2022.164077