Effect of re-solution treatment on microstructure and mechanical property of nickel-base alloy Inconel 718

Abstract

The microstructures and mechanical properties of Inconel 718 alloy were analyzed by using 982 ℃ water cooled solid solution bar after repeated solution and re-aging treatment, and compared with direct aging treatment.The effects of repeated solution treatment temperatures ranging from 941 to 1010 ℃ on microstructures and mechanical properties of the alloy were systematically studied. The results show that with the increase of repeated solution temperature, the content of γ′′ phase / δ phase gradually increases / decreases with no obvious change in grain size, leading to an evident improvement on room-temperature hardness, high-temperature tensile strength and stress-rupture life of the alloy. The maximum values of the tensile elongation and the stress rupture ductility are reached at the repeated solution temperature of 982 ℃. As compared to the direct aging treatment condition, there is no apparent change in microstructure and mechanical properties of the alloy aged after the repeated solution treatment at 982℃. On the contrary to the higher repeated solution temperature, the lower repeated temperature produces unfavorable effect on the mechanical properties.

Keywords

• inconel 718
• re-solution treatment
• solution temperature
• microstructure
• mechanical property