Kinetics of the electrochemical processes at the crack tip in corrosion cracking of titanium alloys

1987 ◽  
Vol 22 (5) ◽  
pp. 461-464
Author(s):  
N. A. Fedotov ◽  
M. V. Soltovets ◽  
V. F. Luk'yanov
Keyword(s):  
Titanium Alloys ◽  
Crack Tip ◽  
Corrosion Cracking ◽  
Electrochemical Processes ◽  
Kinetics Of

The Ordered Phase Formation in Ti-Al-Ga Alloys

1970 ◽  
Vol 28 ◽  
pp. 440-441
Author(s):  
Shiro Fujishiro ◽  
Harold L. Gegel
Keyword(s):  
Thermal Stability ◽  
High Temperature ◽  
Titanium Alloys ◽  
Growth Kinetics ◽  
Stoichiometric Composition ◽  
Good Potential ◽  
Alpha Titanium ◽  
Cold Rolled ◽  
Kinetics Of ◽  
Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

Modeling the Interactions of Hydrogen, Stress and Dissolution in Near-Neutral pH Stress Corrosion Cracking of Pipelines

2006 ◽  
Author(s):  
Frank Y. Cheng
Keyword(s):  
Stress Corrosion ◽  
Dissolution Rate ◽  
Crack Growth ◽  
Anodic Dissolution ◽  
Hydrogen Concentration ◽  
Stress Corrosion Cracking ◽  
Crack Tip ◽  
Corrosion Cracking ◽  
Neutral Ph ◽  
Ph Stress

A thermodynamic model was developed to determine the interactions of hydrogen, stress and anodic dissolution at the crack-tip during near-neutral pH stress corrosion cracking in pipelines. By analyzing the free-energy of the steel in the presence and absence of hydrogen and stress, it is demonstrated that a synergism of hydrogen and stress promotes the cracking of the steel. The enhanced hydrogen concentration in the stressed steel significantly accelerates the crack growth. The quantitative prediction of the crack growth rate in near-neutral pH environment is based on the determination of the effect of hydrogen on the anodic dissolution rate in the absence of stress, the effect of stress on the anodic dissolution rate in the absence of hydrogen, the synergistic effect of hydrogen and stress on the anodic dissolution rate at the crack-tip and the effect of the variation of hydrogen concentration on the anodic dissolution rate.

Efficiency of Microstructure Refinement in Ti-Based Alloys

2021 ◽  
Vol 1016 ◽  
pp. 1753-1758
Author(s):  
Sergey Zherebtsov ◽  
Nikita Stepanov ◽  
Gennady Salishchev
Keyword(s):  
Plastic Deformation ◽  
Chemical Composition ◽  
Titanium Alloys ◽  
Microstructure Evolution ◽  
Large Plastic Deformation ◽  
Two Phase ◽  
Microstructure Refinement ◽  
Kinetics Of ◽  
Rate Type ◽  
Lamellar Type

The influence of various factors on the efficiency of microstructure refinement in two-phase titanium alloys with respect to a well-known Ti-6Al-4V alloy was discussed. The kinetics of microstructure evolution in titanium alloys with a lamellar type α/β microstructure during large plastic deformation depends mainly on temperature and strain rate, type of the initial microstructure, thickness of the α lamellae, path of deformation and chemical composition. Each parameter should be controlled to provide the most efficient microstructure refinement during conventional metalforming methods.

Study on Transition of Stress Corrosion Cracking to Sharp Edge Corrosion for a Liquids Pipeline

2018 ◽  
Author(s):  
Jiajun (Jeff) Liang ◽  
Ziqiang (Alex) Dong ◽  
Mengshan Yu ◽  
Mariko Dela Rosa ◽  
Gurwinder Nagra
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Synergistic Effects ◽  
Management Strategies ◽  
Crack Tip ◽  
Corrosion Cracking ◽  
Lessons Learned ◽  
Sharp Edge ◽  
Maximum Pressure ◽  
Arrest Growth

Although stress corrosion cracking (SCC) growth is attributed to the synergistic effects of stress and corrosion, these two factors can just as easily become competing mechanisms, with stress cycles driving growth (hydrogen, the by-product of corrosion, may facilitate the growth), and corrosion working to blunt the crack tip and arrest growth. It follows that reducing the maximum pressure and cycling severity can slow down the crack growth or even stop it, and aggressive corrosion can further blunt the sharp crack tip. The Authors have observed, on a particular Polyethylene (PE) tape coated pipeline, instances where SCC has exhibited a propensity to corrode and convert into sharp edge corrosion. This is attributed to the combined effects of limited corrosion protection and low stresses. The focus of the paper is to assist operators in recognizing this phenomenon and integrate lessons learned into pipeline integrity management strategies.

Effects of solute oxygen on kinetics of diffusionless isothermal ω transformation in β-titanium alloys

2020 ◽  
Vol 188 ◽  
pp. 88-91
Author(s):  
Norihiko L. Okamoto ◽  
Shuhei Kasatani ◽  
Martin Luckabauer ◽  
Masakazu Tane ◽  
Tetsu Ichitsubo
Keyword(s):  
Titanium Alloys ◽  
Kinetics Of
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