High Temperature Creep, Fatigue and Creep/Fatigue Interaction Behavior of γ' Strengthened Austenitic Iron-Base Superalloy

Xie, Xi Shan; Mao, Zhengdong; Dong, Jin‐Yong; Hu, Yaohe

doi:10.4028/0-87849-978-4.1458

Cited by 2 publications

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“…Most of hot rotating components are working at complicated stress conditions such as at high temperature creep and fatigue interaction conditions. A creep and fatigue interaction fracture map, the new criterion of high temperature materials evaluation as described in reference [5], has been made for the comparison between air-melted and vacuum melted GH871 Experimental results show that VIM GH871 has longer cycles to failure than AIM GH871 (see Fig. 5) because of its high strength and ductility improvement (especially high temperature stress rupture and good ductility as shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

High Temperature Creep, Fatigue and Creep/Fatigue Interaction Behavior of γ' Strengthened Austenitic Iron-Base Superalloy

Xie

Mao²,

Dong

et al. 2005

KEM

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A new modified Nb-containing A-286 γ' strengthened austenitic Fe-base superalloy (14Cr- 28Ni-1.5Mo-1W-2Ti-Nb-Al) designated as GH871 in China characterizes with high level of tensile, stress rupture and low cycle fatigue properties at 650°C. However, the stress rupture ductility is low and the crack propagation rates at 650°C creep or creep/fatigue interaction conditions are high. For ductility and crack propagation behavior improvement vacuum melted GH871 can still keep its high strength level, also raise stress rupture ductility and simultaneously to decrease crack propagation rates at 650°C. Our results support GH871 to be used as a disk material in high temperature industry.

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Section: Resultsmentioning

confidence: 99%

High Temperature Creep, Fatigue and Creep/Fatigue Interaction Behavior of γ' Strengthened Austenitic Iron-Base Superalloy

Xie

Mao²,

Dong

et al. 2005

KEM

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An investigation on thermodynamics and kinetics of η phase formation in Nb-modified iron-nickel base A286 superalloy

Gilakjani

Razavi

Seifollahi

2020

Metall. Res. Technol.

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In this study, precipitation of η phase (Ni3Ti) in conventional and Nb-modified (Nb-A286) A286 superalloys was evaluated at different aging times and temperatures. The TTP curve of the η phase formation was plotted using thermodynamic analyses, kinetics and microstructural studies. Depending on temperature and heat treatment, the η phase precipitated at the grain boundaries or twin sites, as a result of the γ′ phase or matrix austenite transformation. Heat treatment of conventional A286 superalloy and Nb-A286 was performed within a temperature range of 650 to 900 °C for 2 to 30 h. The η phase transformation was evaluated by scanning electron microscope (SEM) which is equipped to energy dispersive X-ray spectroscopy (EDS) and optical microscopy (OM). In the analyses based on thermodynamic calculations, the interaction of the Gibbs free energy of η phase formation and the diffusion activation energy of the elements, especially titanium and niobium, was considered. The microstructural studies showed that increasing the heat treatment time results in increasing the volume fraction of the η phase. By increasing the aging temperature to 840 and 860 °C for conventional A286 superalloy and Nb-A286 superalloy, respectively, the η phase volume fraction increased, however, further increase led to volume fraction decrease. The results of the thermodynamic analyses showed the tip of the TTP diagrams at temperatures of 860 and 820 °C for the A286 and Nb-A286 alloys, respectively. Investigation of kinetics calculations showed that η phase transformation depends on the diffusion of titanium, nickel, and niobium.

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High Temperature Creep, Fatigue and Creep/Fatigue Interaction Behavior of γ' Strengthened Austenitic Iron-Base Superalloy

Cited by 2 publications

References 0 publications

High Temperature Creep, Fatigue and Creep/Fatigue Interaction Behavior of γ' Strengthened Austenitic Iron-Base Superalloy

High Temperature Creep, Fatigue and Creep/Fatigue Interaction Behavior of γ' Strengthened Austenitic Iron-Base Superalloy

An investigation on thermodynamics and kinetics of η phase formation in Nb-modified iron-nickel base A286 superalloy

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