Oxidation behaviour of alloy 800 in an impure helium atmosphere at high temperatures

In-beam fatigue behavior of F82H steel at 500 °C

“…They have also pointed out that the intergranular oxidation could be attributed to the depletion of Cr resulting from the selective removal of Cr from the matrix into the external scale [7]. The injection and diffusion of Kirkendall vacancies followed by selective removal of Cr would play an important role in not only producing voids at various interfaces but also providing easy diffusion paths for oxygen from the surface to form oxides at the grain boundaries [7]. The interaction between oxidation and plastic deformation during cyclic loading has been indicated for various alloys tested in air at higher temperatures [9][10][11][12].…”

“…Since the oxidation could not be observed by SEM measurements on the surfaces of both in-beam and unirradiated specimens, it was assumed that the LT-type dynamic irradiation effect would be little influenced in such a low oxygen potential condition at 60°C. However at higher temperatures, it is well known that some alloying elements are selectively oxidized to form an oxide scale on the alloy surface even in the low oxygen potential atmosphere [7,8]. Shida et al [7] have reported the formation of chromium oxide scales on the surface of Alloy 800 in the impure He atmosphere of the simulated HTGR (high temperature gas-cooled reactors) environment at temperatures ranging from 700 to 850°C.…”

“…However at higher temperatures, it is well known that some alloying elements are selectively oxidized to form an oxide scale on the alloy surface even in the low oxygen potential atmosphere [7,8]. Shida et al [7] have reported the formation of chromium oxide scales on the surface of Alloy 800 in the impure He atmosphere of the simulated HTGR (high temperature gas-cooled reactors) environment at temperatures ranging from 700 to 850°C. They have also pointed out that the intergranular oxidation could be attributed to the depletion of Cr resulting from the selective removal of Cr from the matrix into the external scale [7].…”

“…Shida et al [7] have reported the formation of chromium oxide scales on the surface of Alloy 800 in the impure He atmosphere of the simulated HTGR (high temperature gas-cooled reactors) environment at temperatures ranging from 700 to 850°C. They have also pointed out that the intergranular oxidation could be attributed to the depletion of Cr resulting from the selective removal of Cr from the matrix into the external scale [7]. The injection and diffusion of Kirkendall vacancies followed by selective removal of Cr would play an important role in not only producing voids at various interfaces but also providing easy diffusion paths for oxygen from the surface to form oxides at the grain boundaries [7].…”

The Control of Oxidation-Induced Intergranular Embrittlement by Grain Boundary Engineering in Rapidly Solidified Ni-Fe Alloy Ribbons

“…Polycrystalline materials often suffer from oxidation and corrosion during heat-treatment, hot-working and service in air or reactive environments at high temperatures in the case that extremely deep penetration of oxidation along grain boundaries can take place inside the materials. [1][2][3][4] Such oxidation morphology is termed ''intergranular oxidation'' or ''grain boundary oxidation''. Intergranular oxidation is particularly detrimental to the strength of polycrystalline materials at high temperatures.…”