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

• DOI: 10.1016/j.msea.2005.08.126
• Publication Date: 2005-09-27T14:19:28Z
• Authors: H. Yuan; W.C. Liu
• Keywords: Inconel; Flow stress

Abstract 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.