Effect of the δ phase on the hot deformation behavior of Inconel 718

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Structural materials : properties, microstructure and processing, 2005-11, Vol.408 (1), p.281-289
• Main Authors: Yuan, H., Liu, W.C.
• Format: Article
• Language: English
• Subjects: Applied sciences; Dynamic recrystallization; Elasticity. Plasticity; Exact sciences and technology; Hot deformation; Inconel 718; Mechanical properties and methods of testing. Rheology. Fracture mechanics. Tribology; Metals. Metallurgy; δ Phase
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2005.08.126

Hot compression tests at different temperatures and strain rates were performed on Inconel 718 solution treated as well as solution treated and then aged at 900 °C for 1–24 h in order to investigate the effect of the δ phase on hot deformation behavior. A hyperbolic-sine Arrhenius-type equation was used to characterize the dependence of the peak stress on deformation temperature and strain rate. In the case of Inconel 718 with a large amount of the δ phase, the apparent activation energy was determined to be 458 kJ/mol, which was slightly higher than the activation energy of 443 kJ/mol for solution treated Inconel 718. The γ″/γ′ phases present in Inconel 718 prior to hot deformation enhanced the peak stress, but did not affect the peak strain. The δ phase present in Inconel 718 not only decreased the peak strain and the peak stress, but also promoted the flow softening after the peak stress.