The intergranular oxidation susceptibility of thermally–treated Alloy 600

Abstract

The oxidation behaviour of thermally-treated Alloy 600 was studied using hydrogenated steam at 480°C, environment known to simulate pressurized water reactors conditions, and subsequently analyzed using analytical electron microscopy. Focused Ion Beam and analytical transmission electron microscopy provided definitive evidence of localized intergranular carbides decomposition and the formation of an intergranular Cr-rich oxide embryo. These results are discussed in this paper in terms of early stages of preferential intergranular oxidation and grain boundary migration, carbide decomposition, GB pinning and the effect of local carbon enrichments in the matrix.

Internal Oxidation of a Fe–Cr Binary Alloy at 700–900 °C: The Role of Hydrogen and Water Vapor

“…A very similar corrosion phenomenon is well known to occur in nuclear materials exposed to pressurized water reactor (PWR) primary water environment: intergranular stress corrosion cracking (IGSCC). For the first time reported for 304 and 347 steel pipes in the 1960s [58], IGSCC was later observed also in Ni-based alloys [59] such as alloy 600 [60][61][62]. It is generally accepted that IGSCC is the caused by internal oxidation [63].…”

Проблемы Коррозии И Физико-Механические Модели Разрушения Конструкционных Материалов Для Энергомашиностроения

“…На основе работ [4][5][6][7][8][9][10][11][12][13][14][15][16][17], выполненных методами рентгеновской дифракции, сканирующей микро скопии, рентгеновской фотоэлектронной спектро скопии, наблюдаются следующие общие призна ки. Продукты коррозии в аустенитных сталях со стоят из пористого внешнего и плотного внутрен него оксидного слоя.…”

The effects of intergranular carbides on the grain boundary oxidation and cracking in a cold-worked Alloy 600

“…Alloy 600 is frequently reported to have high stress corrosion cracking (SCC) susceptibility in pressurized water reactor (PWR) primary water over the past decades [1][2][3][4][5][6][7]. Domian et al [8] were the first to develop a method for increasing the SCC resistance of Alloy 600 by thermal treatment.…”

“…Specifically, mill-annealed (MA) or solution-annealed (SA) alloys exhibited higher SCC susceptibility than thermally-treated (TT) alloys due to a lower IC coverage [8][9][10]. Subsequent research revealed that a semi-continuous network of ICs can also reduce SCC susceptibility effectively in hydrogenated steam environments [6,7,11,[12][13][14][15][16][17][18][19][20][21].…”