EXPERIMENTAL INVESTIGATION AND THERMODYNAMIC CALCULATION ON PHASE PRECIPITATION OF INCONEL 740
来源期刊：Acta Metallurgica Sinica2006年第6期
论文作者：J.X. Dong S.Q. Zhao X.S. Xie Y. Jiang
Key words：superalloy; INCONEL 740; precipitate; thermodynamic calculation;
Abstract: A novel nickel-based superalloy INCONEL 740 was under development for application in ultra-supercritical superheater tubers above 750℃. The precipitation behaviors of η phase andγ′ particles of the alloy were investigated through experimental study and phase computation.Experimental results showed that η phase formed a Widmanst(a)tten pattern structure following long-term exposure at elevated temperatures and that the coarsening of γ′ particle follows a cube rate law: (r)3 ∝t. Thermodynamic calculation results showed that Al and Ti had an important effect on the precipitation behavior of γ′ and η phases. Two suggested novel modified alloys, wherein the Al and Ti contents were modified, were designed and melted for the experimental study. The preliminary results indicated that the modified alloys exhibited higher structural stability following long-term exposure at 750℃ till 5000h.
J.X. Dong1，S.Q. Zhao2，X.S. Xie1，Y. Jiang3
(1.High Temperature Materials Research Laboratories, University of Science and Technology Beijing,Beijing 100083, China;
2.Department of Physics, Ningxia University, Yinchuan 750021, China;
3.Department of Materials Science, The Northwest Second Nationalities Institute, Yinchuan 750021, China)
Abstract:A novel nickel-based superalloy INCONEL 740 was under development for application in ultra-supercritical superheater tubers above 750℃. The precipitation behaviors of η phase andγ′ particles of the alloy were investigated through experimental study and phase computation.Experimental results showed that η phase formed a Widmanst(a)tten pattern structure following long-term exposure at elevated temperatures and that the coarsening of γ′ particle follows a cube rate law: (r)3 ∝t. Thermodynamic calculation results showed that Al and Ti had an important effect on the precipitation behavior of γ′ and η phases. Two suggested novel modified alloys, wherein the Al and Ti contents were modified, were designed and melted for the experimental study. The preliminary results indicated that the modified alloys exhibited higher structural stability following long-term exposure at 750℃ till 5000h.
Key words:superalloy; INCONEL 740; precipitate; thermodynamic calculation;
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