A study on tensile properties of Alloy 709 at various temperatures

Journal Article · Sat Jun 23 00:00:00 EDT 2018 · Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing

DOI:https://doi.org/10.1016/j.msea.2018.06.089· OSTI ID:1538615

Upadhayay, Swathi ^[1]; Li, Hangyue ^[2]; Bowen, Paul ^[2]; Rabiei, Afsaneh ^[1]

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1. North Carolina State University, Raleigh, NC (United States)
2. University of Birmingham (United Kingdom)

In recent years, there have been several advancements in energy production from both fossil fuels and the alternate “clean” sources such as nuclear fission. These advancements are fueled by the need for more efficient systems that will optimize the use of the depleting fossil fuel reserves and shift the focus to cleaner sources of energy. The efficiency of any power generation cycle is dependent on the ability of the structural material to withstand increased peak operating temperatures. Advanced austenitic stainless steels have been in the focus as structural material for the next generation nuclear power plants, due to their strength, corrosion resistance, weldability and the wide range of temperatures at which the austenite phase is stable. Alloy 709, a recently developed advanced austenitic stainless steel, is being investigated in this paper. Here in this study, tensile tests were conducted on dog-bone samples of Alloy 709 in an in-situ scanning electron microscope (SEM) loading and heating stage, equipped with electron backscatter diffraction (EBSD), at various temperatures. The in-situ experiments indicated that the material primarily accommodated deformation by slip at lower temperatures. Void formation and coalescence at grain boundaries preceded slip at higher temperatures. Although crack initiation at all elevated temperatures was intergranular, the crack propagation through the material and the final fracture was transgranular ductile. Additionally, tensile tests were conducted on larger cylindrical samples at 550, 650 and 750 °C in air. The results of tests conducted in air and in-situ were found to be in agreement, at these temperatures.

• Research Organization: North Carolina State University, Raleigh, NC (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE), Nuclear Energy University Program (NEUP); Research Council of United Kingdom (RCUK); USDOE
• Grant/Contract Number: NE0008451; EP/N016351/1; 2015-1877/DE-NE0008451
• OSTI ID: 1538615
• Alternate ID(s): OSTI ID: 1544588
• Journal Information: Materials Science and Engineering. A, Structural Materials: Properties, Microstructure and Processing, Vol. 733, Issue C; ISSN 0921-5093
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
austenitic stainless steel
alloy 709
Fractography
in-situ scanning electron microscope
electron backscatter diffraction