The Structure and Mechanical Properties of Alloy 718 DA Disk on Hammer

Inconel 718(Ni-19Cr-18Fe-3Mo-5Nb-1Ti-0.5Al) nickel-base superalloy strengthened mainly by Ni3Nb type γ″ and partially by Ni3Al type γ′ precipitation is today’s most widely used superalloy in the world. China has paid special attention on Inconel 718 research and development. Systematic long-term research project has been conducted in close cooperation among our university, research institutes and factories. The goal of this long-term project is in 2 steps. First step is to improve Alloy 718 to get high quality and the second step is for improving the alloy temperature capability from 650oC to 680-700oC. The basic idea for alloy improvement is still to keep the chemical composition in the range of specification by small adjustment or control of minor elements, such as S, P, N, Si and Mg. The main achievements are segregation control by adjustment of S, P, Si, control of N for cleanliness, micro-alloying of Mg for grain boundary strengthening and control of low S and high P for stress rupture life improvement. Modification of Alloy 718 is based on structure stability study and its improvement in adjustment of main second phase strengthening alloy elements Nb, Ti and Al in total amount and the ratios among them. The goal is to achieve more stable second phase strengthening by control of alloy elements. Experimental results show that the future of modified 718 alloys is very attractive to raise the temperature capability improvement from 650oC to 680-700oC.

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The Effects of 650�C Long Exposure on Alloy 718 DA Disk

Liang¹,

Yang²,

Zhang³

et al. 2001

Superalloys 718, 625, 706 and Various Derivatives (2001)

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1111 isothermal aging study was carried out on alloy 718 DA disk for up to 1000 hours at the temperature of 650°C. There was almost no changing in the size and main amount of itrengthening phase u " , and the mechanical properties are also unchanged when allo) 71 8 DA disk was exposed for 500 hours at the temperature of 650°C. When the disk mas exposed to 1000 hours at the temperature of 650°C. although tensile properties remained stable, but h ' size became increasing, hr ' I amount decreasing and stress rupture, creep and low c) cle fatigue properties had a evident changing. The stress rupture time only had about a half of the rupture time of DA718 disk. The remained plastic strain had a larger increase in the creep tests and the abllitj of resistance against plastic strain weakened at 650°C low cqcle fatigue experiment when the DA disk was exposed to 1000 hours at the temperature of 650°C. The change of strengthening phase Y " in size and amount will cause the variation in some mechanical properties on alloy 71 8 DA disk.

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The Structure and Mechanical Properties of Alloy 718 DA Disk on Hammer

Cited by 3 publications

References 1 publication

Effects of processing heterogeneities on the micro- to nanostructure strengthening mechanisms of an alloy 718 turbine disk

Effects of processing heterogeneities on the micro- to nanostructure strengthening mechanisms of an alloy 718 turbine disk

Research and Development of Inconel 718 Type Superalloy

The Effects of 650�C Long Exposure on Alloy 718 DA Disk

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