Grain boundary chromium depletion in austenitic alloys

2010 ◽  
Vol 45 (21) ◽  
pp. 5872-5882 ◽  
Author(s):  
Youfa Yin ◽  
Roy G. Faulkner ◽  
Paul Moreton ◽  
Ian Armson ◽  
Peter Coyle
Keyword(s):  
Grain Boundary ◽  
Chromium Depletion ◽  
Austenitic Alloys

Prevention of Corrosion in Austenitic Stainless Steel through a Predictive Numerical Model Simulating Grain Boundary Chromium Depletion

2017 ◽  
pp. 374-389
Author(s):  
M.K. Samal
Keyword(s):  
Mathematical Model ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Numerical Model ◽  
Low Temperature ◽  
Grain Boundary ◽  
Stainless Steels ◽  
Predictive Models ◽  
Chromium Depletion ◽  
Sensitization Behavior

In this chapter, a mathematical model for rate of formation of chromium carbides near the grain boundary, which is a pre-cursor to chromium depletion and corresponding sensitization behavior in stainless steels, is presented. This model along with the diffusion equation for chromium in the grain has been used to obtain chromium depletion profiles at various time and temperature conditions. Finite difference method has been used to solve the above equations in the spherical co-ordinate system and the results of time-temperature-sensitization diagrams of four different types of alloys have been compared with those of experiment from literature. For the problem of low temperature sensitization and corresponding inter-granular corrosion in austenitic stainless steel, it is very difficult to carry out experiment at higher temperatures and justify its validity at lower operating temperatures by extrapolation. The development of predictive models is highly useful in order to design the structures for prevention of corrosion of the material in aggressive environments.

scholarly journals On the Role of Grain Size and Carbon Content on the Sensitization and Desensitization Behavior of 301 Austenitic Stainless Steel

Metals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 1193 ◽  
Author(s):  
Kolli ◽  
Javaheri ◽  
Kömi ◽  
Porter
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Grain Boundary ◽  
Carbon Content ◽  
Double Loop ◽  
Boundary Carbide ◽  
Self Healing ◽  
Chromium Depletion ◽  
Electrochemical Potentiokinetic Reactivation

The effect of grain size in the range 72 to 190 μm and carbon content in the range 0.105–0.073 wt.% on the intergranular corrosion of the austenitic stainless steel 301 has been investigated. Grain boundary chromium depletion has been studied directly using energy dispersive X-ray spectroscopy combined with scanning transmission electron microscopy and indirectly using double loop electrochemical potentiokinetic reactivation tests. In addition, chromium depletion has been modelled using the CALPHAD Thermo-Calc software TC-DICTRA. It is shown that the degree of sensitization measured using the double loop electrochemical potentiokinetic reactivation tests can be successfully predicted with the aid of a depletion parameter based on the modelled chromium depletion profiles for heat treatment times covering both the sensitization and de-sensitization or self-healing. Additionally, along with intergranular M23C6 carbides, intragranular M23C6 and Cr2N nitrides that affect the available Cr for grain boundary carbide precipitation were also observed.

Intergranular Corrosion Behavior of 00Cr12 Ferritic Stainless Steels Containing Cerium

2013 ◽  
Vol 690-693 ◽  
pp. 133-138
Author(s):  
Ya Bo Li ◽  
Fu Ming Wang ◽  
Xiao Nong Cheng
Keyword(s):  
Grain Boundary ◽  
Corrosion Behavior ◽  
Stainless Steels ◽  
Intergranular Corrosion ◽  
Optical Microscope ◽  
Mechanism Analysis ◽  
Chromium Depletion ◽  
Ferritic Stainless Steels ◽  
Boundary Density ◽  
Grain Sizes

Intergranular corrosion behavior of 00Cr12 ferritic stainless steels with different amounts cerium was evaluated. For this evaluation, electrochemical measurements - polarization curves - were obtained for tested materials, and optical microscope was used to observe corrosive microstructure. Experimental results shows: cerium reduces grain sizes and improves intergranular corrosion resistance of test materials. Through mechanism analysis: cerium reduces grain sizes, increases grain boundary density, therefore might improve distribution aspects of carbides and nitrides, chromium depletion situation near grain boundary would be improved, this work worth further study.

Localized Deformation Induced IGSCC and IASCC of Austenitic Alloys in High Temperature Water

2004 ◽  
Vol 261-263 ◽  
pp. 885-902 ◽  
Author(s):  
G.S. Was ◽  
B. Alexandreanu ◽  
J. Busby
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Localized Deformation ◽  
High Temperature Water ◽  
Austenitic Alloys ◽  
Temperature Water

Grain boundary properties are known to affect the intergranular stress corrosion cracking (IGSCC) and irradiation assisted stress corrosion cracking behavior of austenitic alloys in high temperature water. However, it is only recently that sufficient evidence has accumulated to show that the disposition of deformation in and near the grain boundary plays a key role in intergranular cracking. Grain boundaries that can transmit strain to adjacent grains can relieve stresses without undergoing localized deformation. Grain boundaries that cannot transmit strain will either experience high stresses or high strains. High stresses can lead to wedge-type cracking and sliding can lead to rupture of the protective oxide film. These processes are also applicable to irradiated materials in which the deformation can become highly localized in the form of dislocation channels and deformation twins. These deformation bands conduct tremendous amounts of strain to the grain boundaries. The capability of a boundary to transmit strain to a neighboring grain will determine its propensity for cracking, analogous to that in unirradiated metals. Thus, IGSCC in unirradiated materials and IASCC in irradiated materials are governed by the same local processes of stress and strain accommodation at the boundary.

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