Orientational growth behavior and mechanism of delta (δ) phase precipitation in cold-rolled Inconel 718 alloy during heat treatment
Neng-yong Ye1, Guang-liang Zhang1, Tian-yue Huang1, Ming Cheng2, Shi-hong Zhang2, Lei Wang1
1 School of Materials Science & Engineering, Taizhou University, Taizhou 318000, Zhejiang, China 2 Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, Liaoning, China
Orientational growth behavior and mechanism of delta (δ) phase precipitation in cold-rolled Inconel 718 alloy during heat treatment
Neng-yong Ye1, Guang-liang Zhang1, Tian-yue Huang1, Ming Cheng2, Shi-hong Zhang2, Lei Wang1
1 School of Materials Science & Engineering, Taizhou University, Taizhou 318000, Zhejiang, China 2 Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, Liaoning, China
摘要 Due to the important role of δ phase’s quantity and morphology in the mechanical and fatigue properties of Inconel 718 alloy and its components, it is necessary to renew insights into the effect of cold deformation on the δ phase precipitation, especially on the morphology evolution. Therefore, the nucleation and growth behavior of δ phase in cold-rolled Inconel 718 alloy during aging were investigated. The results show that the precipitation rate and volume fraction of δ phase increase with increasing the cold rolling reduction from 10% to 50%. The volume fraction of δ phase reaches equilibrium after 5 h, remaining at 5.98%, 6.52%, and 6.79% under different rolling reductions (10%, 30%, and 50%), respectively. The nucleation of δ phase mainly occurs on different sites (grain boundaries, new twin boundaries and old twin boundaries) under 10% rolling reduction, while δ phase mainly nucleates on the new grain boundaries of static recrystallization due to 50% rolling reduction. And the growth of δ phase undergoes a process of alternate orientation growth from spherical (nucleation) → short rod (longitudinal orientation growth) → short rod (radial orientation growth) → dynamic equilibrium. Under 10% rolling reduction, δ phase tends to grow into the matrix, while under 50% rolling reduction, the orientation grows faster and is easily affected by the grain boundary curvature.
Abstract：Due to the important role of δ phase’s quantity and morphology in the mechanical and fatigue properties of Inconel 718 alloy and its components, it is necessary to renew insights into the effect of cold deformation on the δ phase precipitation, especially on the morphology evolution. Therefore, the nucleation and growth behavior of δ phase in cold-rolled Inconel 718 alloy during aging were investigated. The results show that the precipitation rate and volume fraction of δ phase increase with increasing the cold rolling reduction from 10% to 50%. The volume fraction of δ phase reaches equilibrium after 5 h, remaining at 5.98%, 6.52%, and 6.79% under different rolling reductions (10%, 30%, and 50%), respectively. The nucleation of δ phase mainly occurs on different sites (grain boundaries, new twin boundaries and old twin boundaries) under 10% rolling reduction, while δ phase mainly nucleates on the new grain boundaries of static recrystallization due to 50% rolling reduction. And the growth of δ phase undergoes a process of alternate orientation growth from spherical (nucleation) → short rod (longitudinal orientation growth) → short rod (radial orientation growth) → dynamic equilibrium. Under 10% rolling reduction, δ phase tends to grow into the matrix, while under 50% rolling reduction, the orientation grows faster and is easily affected by the grain boundary curvature.
Neng-yong Ye,Guang-liang Zhang,Tian-yue Huang, et al. Orientational growth behavior and mechanism of delta (δ) phase precipitation in cold-rolled Inconel 718 alloy during heat treatment[J]. Journal of Iron and Steel Research International, 2024, 31(1): 264-274.
2024, Vol. 31 
