Evaluating the efficiency of grain boundary serrations in attenuating high-temperature hot corrosion degradation in Alloy 617

Alloy 617 is the leading candidate material for an intermediate heat exchanger (IHX) application of the Very High Temperature Nuclear Reactor (VHTR), expected to have an outlet temperature as high as 950°C. Acceptance of Alloy 617 in Section III of the ASME Code for nuclear construction requires a detailed understanding of the creep-fatigue behavior. Initial creep-fatigue work on Alloy 617 suggests a more dominant role of environment with increasing temperature and/or hold times evidenced through changes in creep-fatigue crack growth mechanism/s and failure life. Furthermore, previous work on corrosion of nickel base alloys in impure helium has suggested that this environment is far from inert with respect to Alloy 617. Continuous cycle fatigue and creep-fatigue testing of Alloy 617 was conducted at 950°C and 0.3% and 0.6% total strain in air to simulate damage modes expected in a VHTR application. Continuous cycle and creep-fatigue specimens exhibited intergranular cracking, but did not show evidence of grain boundary cavitation. Despite the absence of grain boundary cavitation to accelerate crack propagation, the addition of a hold time at peak tensile strain was detrimental to cycle life. This suggests that creep-fatigue interaction may occur by a different mechanism or that the environment may be partially responsible for accelerating failure.

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Formation of Serrated Grain Boundaries and Its Effect on Tensile Properties at 950 ℃ in Alloy 617 for Very High Temperature Reactor

Korean Journal of Metals and Materials ◽

10.3365/kjmm.2014.53.1.1 ◽

2015 ◽

Vol 53 (1) ◽

pp. 1-12 ◽

Cited By ~ 5

Author(s):

Hyun Uk Hong ◽

June Woo Choi ◽

Ji Won Lee ◽

Je Hyun Lee ◽

Dong Jin Kim

Keyword(s):

High Temperature ◽

Grain Boundaries ◽

Tensile Properties ◽

Alloy 617 ◽

Very High Temperature Reactor ◽

High Temperature Reactor ◽

Very High

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Dopant effect on high-temperature plastic flow behavior and grain boundary chemistry in oxide ceramics

Zeitschrift für Metallkunde ◽

10.3139/146.101007 ◽

2005 ◽

Vol 96 (2) ◽

pp. 108-116

Author(s):

Hidehiro Yoshida ◽

Yuichi Ikuhara ◽

Taketo Sakuma

Keyword(s):

High Temperature ◽

Grain Boundary ◽

Plastic Flow ◽

Flow Behavior ◽

Oxide Ceramics ◽

Dopant Effect ◽

Boundary Chemistry

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ROLLED ALLOYS HR-120

Alloy Digest ◽

10.31399/asm.ad.ni0561 ◽

2000 ◽

Vol 49 (10) ◽

Keyword(s):

Corrosion Resistance ◽

High Temperature ◽

Physical Properties ◽

Tensile Properties ◽

Oxidation Resistance ◽

Thermal Processing ◽

Hot Corrosion ◽

Heat Treating ◽

Temperature Performance

Abstract HR-120 alloy is an alloy designed for thermal processing. It possesses excellent strength, oxidizing hot corrosion resistance, good carburization resistance, and oxidation resistance through 1093 deg C (2000 deg F). This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: Ni-561. Producer or source: Rolled Alloys.

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