A Grain Boundary Engineering Approach to Materials Reliability

1996 ◽  
Vol 458 ◽  
Author(s):  
G. Palumbo ◽  
E. M. Lehockey ◽  
P. Lin ◽  
U. Erb ◽  
K. T. Aust
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Boundary Structure ◽  
Polycrystalline Materials ◽  
Grain Boundary Engineering ◽  
Structure Property ◽  
Engineering Approach

ABSTRACTIntergranular degradation processes, (e.g., corrosion, stress corrosion, cracking, creep cracking) are a frequent cause of premature and unpredictable service failure of engineering components. Recent advances in (1) understanding structure-property relationships for grain boundaries, and (2) characterization techniques for grain boundaries in polycrystalline materials, have provided the means for improved component lifetime prediction, and the opportunity to engineer intergranular-degradation resistant microstructures.In this work, we present our previously developed geometric models for grain boundary structure and grain size effects on intergranular degradation susceptibility. Specific examples are presented of the successful application of the ‘grain boundary engineering’ approach to the prediction and mitigation of intergranular corrosion, stress corrosion cracking, and creep cracking in Ni-based materials.

Grain boundary engineering for improving stress corrosion cracking of 304 stainless steel

2019 ◽  
Vol 35 (4) ◽  
pp. 477-487 ◽  
Author(s):  
Tingguang Liu ◽  
Qin Bai ◽  
Xiangkun Ru ◽  
Shuang Xia ◽  
Xiangyu Zhong ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Grain Boundary ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
304 Stainless Steel ◽  
Grain Boundary Engineering

Application of Microdiffraction in Sem for Assessing Intrinsic Materials Susceptibility to Intergranular Corrosion and Stress Corrosion Cracking

1997 ◽  
Vol 3 (S2) ◽  
pp. 573-574
Author(s):  
G. Palumbo ◽  
E.M. Lehockey ◽  
P. Lin
Keyword(s):  
Grain Boundary ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Service Failure ◽  
Coincidence Site Lattice ◽  
Corrosion Cracking ◽  
Polycrystalline Materials ◽  
Materials Synthesis ◽  
Intergranular Cracking ◽  
Grain Boundary Character

Intergranular degradation processes (e.g., corrosion, stress corrosion cracking) are a frequent cause of premature and unpredictable service failure of engineering components. Since these processes cause component failure via propagation through the intercrystalline network, they are strongly dependent upon the distribution of specific grain boundary structures in the material. Previous studies have shown that grain boundaries crystallographically described by low Σ (Σ≤29) Coincidence Site Lattice (CSL) relationships can often selectively display a high resistance (and often immunity) to corrosion and fracture. Recent advances in automated microdiffraction techniques (e.g., EBSP) in SEM have now made it possible to readily evaluate grain boundary character distributions in conventional polycrystalline materials. by utilizing this technique, and by formulating and applying simple stochastic models for the propagation of intergranular cracking and corrosion processes, the opportunity now exists for (1) improved component lifetime prediction, and (2) the optimization of materials synthesis techniques to yield intergranular-degradation resistant microstructures.

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.

Multiphysics Modeling and Simulation for Stress Corrosion Cracking Considering Oxygen Atom Diffusion Along Grain Boundary

2010 ◽  
Author(s):  
Takahiro Igarashi ◽  
Yoshiteru Aoyagi ◽  
Yoshiyuki Kaji
Keyword(s):  
Grain Boundary ◽  
Crack Propagation ◽  
Grain Boundaries ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Corrosive Environment ◽  
Propagation Behavior ◽  
Crack Tips ◽  
Oxygen Atoms

Aged degradations of structural materials of boiling water reactors by stress corrosion cracking (SCC) have been frequently reported. SCC is the results of the synergistic interaction of mechanical stress and corrosive environment, and the investigation of this phenomenon has been an important issue. Although many kinds of studies for SCC have been carried out, we have not clarified the fundamental mechanisms of SCC initiation and propagation yet. In the recent experimental studies, nano-scale observation around crack tips using transmission electron microscopy have shown three characteristics of SCC of nuclear structural materials as follows; the size of crack tip is nanometer order, the opening crack is filled with the oxides, and oxygen atoms exist in the grain boundary beyond the crack tips. The second and third ones show that the corrosive environment is mainly influenced on the SCC propagation behavior. Furthermore, electron back scatter diffraction pattern analyses have shown that about 10–20% of plastic strain exists around the crack tips and crack sides. The existence of oxygen atoms along grain boundaries and plastic strains around grain boundaries could be related to the crack propagation mechanism of SCC. In this study, in order to observe the influence of oxygen atoms on the SCC propagation behavior, the two-dimensional SCC propagation model considering diffusion of oxygen atoms along grain boundaries is developed. In this model, the stress distribution of polycrystalline system is obtained by the crystal plasticity theory, and the concentration of oxygen atoms depending on stress localization around cracks is calculated using the diffusion equation of oxygen atoms considering the stress gradient. The density distribution of oxygen atoms is adopted for the threshold of the crack propagation. Relation between the threshold of crack propagation as a viewpoint of density of oxygen atoms along grain boundaries and the geometry of SCC is discussed in this paper.

Role of Coincident Site Lattice Boundaries in Creep and Stress Corrosion Cracking

2004 ◽  
Vol 819 ◽  
Author(s):  
G.S. Was ◽  
B. Alexandreanu ◽  
Peter Andresen ◽  
Mukul Kumar
Keyword(s):  
Grain Boundary ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
High Purity ◽  
Coincident Site Lattice ◽  
Corrosion Cracking ◽  
304 Stainless Steel ◽  
Boundary Structure ◽  
Site Lattice

AbstractInterfaces control many properties in engineering materials, several of which are critical to the integrity of the engineering structure. In single phase, solid solution, austenitic alloys, grain boundaries are often the weak link, displaying susceptibility to creep, corrosion and stress corrosion cracking. As such, grain boundary structure control affords the opportunity to improve the overall performance of alloys in a variety of applications. The role of coincident site lattice boundary (CSLB) enhancement and grain boundary connectivity is examined for how it affects the response of an alloy to stress and the environment. Specifically, the effect of grain boundary character on creep, grain boundary sliding, intergranular stress corrosion cracking, and irradiation assisted stress corrosion cracking in austenitic nickel-base (high purity Ni-Cr-Fe and alloy 600) and iron-base (high purity Fe-Cr-Ni and 304 stainless steel) alloys and for ferritic- martensitic alloy T91 is discussed.

scholarly journals Surface grain boundary engineering of Alloy 600 for improved resistance to stress corrosion cracking

2015 ◽  
Vol 648 ◽  
pp. 280-288 ◽  
Author(s):  
Abhishek Telang ◽  
Amrinder S. Gill ◽  
Deepthi Tammana ◽  
Xingshuo Wen ◽  
Mukul Kumar ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Alloy 600 ◽  
Grain Boundary Engineering ◽  
Resistance To Stress

Review of the Stress Corrosion Cracking of Inconel 600

CORROSION ◽  
1975 ◽  
Vol 31 (9) ◽  
pp. 327-337 ◽  
Author(s):  
D. VAN ROOYEN
Keyword(s):  
High Temperature ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Boundary Segregation ◽  
Corrosion Cracking ◽  
Inconel 600 ◽  
High Temperature Water ◽  
Temperature Water

Abstract Intergranular stress corrosion cracking (SCC) of Inconel 600 is of concern to the nuclear power industry. Heat exchangers in commercial nuclear systems have shown SCC in only a fraction of a percent of the tubes in high temperature water, but laboratory SCC of Ni-containing alloys have been demonstrated by several research groups. This review revolves around French data, which show a reversal of the usual sensitizing effect in the case of SCC in high temperature, deaerated water. There is no cracking reported in material first heated so as to precipitate carbides at the grain boundaries, whereas high temperature annealed conditions lead to intergranular SCC in the same laboratory experiments. Electrochemically, SCC and also grain boundary corrosion are related to the potential level of a given test; however, it is not yet understood how the different grain boundary zones in Inconel 600 corrode (with and without applied stress) so that the mechanism of cracking remains speculative. Cr-depletion is sufficient to explain only some cases of intergranular corrosion. Grain boundary segregation seems to be of equal or greater importance in high temperature water, especially when the attack involves SCC. Grain boundaries may become cleaned when segregated elements dissolve in chromium carbide precipitates. Physically, precipitates at grain boundaries could possibly influence the manner in which the metal undergoes strain. Hydrogen as a cause of SCC has not been ruled out. The relationship between surface films formed and SCC of Alloy 600 in high temperature aqueous environments requires more work.

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