Investigation of low stress rupture properties in Inconel-718 super alloy

14th International Symposium on Advanced Materials

Zaman, T.^1 ; Farooque, M.^1 ; Rizvi, S.A.^1 ; Salam, I.^1 ; Waseem, M.^1

Institute of Industrial Control Systems, P. O. Box 1398, Rawalpindi, Pakistan^1

关键词: Aircraft gas turbines;    Creep behaviors;    Creep properties;    Effect of annealing;    Hardening phase;    High temperature stress ruptures;    Primary carbides;    Secondary carbides;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/146/1/012051/pdf
DOI  :  10.1088/1757-899X/146/1/012051

来源: IOP

【 摘 要 】

Inconel-718 is a Ni-Cr-Fe based super alloy. It is widely utilized in aircraft gas turbines, nuclear power systems, space vehicles and medical applications. Aim of the present study is to evaluate the effect of Ti and Nb content on high temperature stress rupture properties of Inconel718. OM, SEM and TEM were utilized for characterization of microstructure. Inconel718 is unique in that it forms large number of phases due to its composition and variety of heat treatments. γ"+ γ' precipitates and the effect of annealing on these precipitates have been studied using TEM. The main hardening phase was identified as metastable Ni3Nb (γ"). Other phases identified after annealing were secondary carbides (NbC) and stable acicular 5 phase. Effect of γ", 5, primary carbides and NbC on creep behavior was observed using OM and SEM. Higher Ti content(1.25 wt. %) resulted in poor creep properties due to large concentrations of primary carbides (TiC) at grain boundaries.