Journal ArticleDOI
The effect of water vapor in increasing growth stresses in the oxide scale on martensitic steam plant alloys
TLDR
In this article, in situ acoustic emission (AE) for monitoring scale cracking, deflection testing in monofacial oxidation (DTMO), and in situ X-ray measurements were complemented by detailed post-experimental metallographic investigations.Abstract:
Investigation of the oxidation behavior of 9% Cr steels at 650°C in dry air and air + 10% H2O have shown that oxide scale growth stresses may play a significant role in breakaway. For this reason, preliminary studies on the development and characteristics of growth stresses in oxides on these materials have begun. These studies include in situ acoustic emission (AE) for monitoring scale cracking, deflection testing in monofacial oxidation (DTMO) and in situ X–ray measurements. The measurements were complemented by detailed post-experimental metallographic investigations.From the DTMO measurements the stresses in the oxide on the specimens tested in humid environment are increased by about a factor of 5 compared to dry air at the beginning of oxidation for P91. In a humid environment the stresses decrease with oxidation time while in dry air they remain almost constant. Significant acoustic emission (AE) occurs in humid air for oxidation coupons while virtually no AE is observed for thin foils in a...read more
Citations
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Journal ArticleDOI
The oxidation behaviour of metals and alloys at high temperatures in atmospheres containing water vapour: A review
TL;DR: In this paper, the effect of water vapour on the formation of a more porous scale is discussed. But, while there is experimental evidence for altered mechanical behaviour, there is very little data on relevant mechanical properties.
Journal ArticleDOI
Water Vapor Effects on the Oxidation Behavior of Fe–Cr and Ni–Cr Alloys in Atmospheres Relevant to Oxy-fuel Combustion
TL;DR: In this article, the oxidation behavior of a number of Fe-Cr and Ni-Cr-based alloys was studied in atmospheres relevant to oxyfuel combustion at 650°C.
Journal ArticleDOI
The Influence of Cr Evaporation on Long Term Cr Depletion Rates in Ferritic Stainless Steels
TL;DR: In this article, the 22% Cr ferritic steel Sanergy HT, intended for use as an SOFC interconnect material, was exposed discontinuously over 3100h at 850°C in air + 3% H2O @ 6000 sml−min−1 (27 cm−s−1) and stagnant conditions in a tubular reactor.
Book ChapterDOI
Stress Effects in High Temperature Oxidation
TL;DR: In this paper, the role of mechanical stresses in high temperature oxidation of metallic materials was described and the different modes of scale failure were discussed and model equations were given quantifying the failure strains.
Journal ArticleDOI
Detection of breakaway oxidation with Acoustic Emission during titanium oxide scale growth
TL;DR: In this article, an extensive in-situ analysis of high temperature breakaway oxidation of titanium metal has been performed using the Acoustic Emission (AE) technique, and a critical energy value of E ǫ = 3 fJ was determined as a frontier between signal resulting from oxide parabolic growth and signals resulting from rapid linear growth.
References
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Book
Protective oxide scales and their breakdown
TL;DR: In this paper, the basic requirements for the Protective Action of Oxide Scales are discussed. And the following diagrams are presented: Oxide Scale Damage Diagrams, Depletion by Oxidation and Crack Healing of Alloying Elements which Form Protective Scales.
Journal ArticleDOI
The role of alloy composition, environment and stresses for the oxidation resistance of modern 9% Cr steels for fossil power stations
TL;DR: In this paper, the influence of alloy composition and metal subsurface zone concentration as a function of oxidation time up to 10000 h was investigated in dry air and air up to 10% water vapour at 650 °C.
Journal ArticleDOI
Role of growth stresses on the structure of oxide scales on nickel at 800 and 900°C
W. Przybilla,Michael Schütze +1 more
TL;DR: In this paper, the development and relief of intrinsic growth stresses in oxide scales on nickel of different purity have been investigated by combining the deflection test in monofacial oxidation (DTMO) with acoustic-emission analysis (AE).
Journal ArticleDOI
Limits of the oxidation resistance of several heat-resistant steels under isothermal and cyclic oxidation as well as under creep in air at 650°C
TL;DR: In order to guarantee the oxidation resistance of Cr-steels, the Cr content in the alloy must be above a critical limit as discussed by the authors, and recently developed 9Cr steels are close to that limit.
Journal ArticleDOI
Parameters determining the breakaway oxidation behaviour of ferritic martensitic 9%Cr steels in environments containing H2O
TL;DR: In this paper, the authors investigated the role of intrinsic growth stresses in the incubation time to breakaway in commercial and quasicommercial versions of P91, E911 and Nf616 steels.