The Relative Stress-Corrosion Susceptibility of Titanium Alloys in the Presence of Hot Salt
The Relative Stress-Corrosion Susceptibility of Titanium Alloys in the Presence of Hot Salt

Author: D. N. Fager

Publisher:

Published: 1966

Total Pages: 22

ISBN-13:

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Steady-state stress-corrosion tests at elevated temperature were performed on three titanium alloys. Mill annealed titanium 6Al-4V was the least susceptible, followed in order of increasing susceptibility by titanium 8Al-1Mo-1V and titanium 6Al-6V-2Sn. Sodium chloride was more detrimental than ASTM synthetic salt. Extensive tests were conducted on duplex annealed titanium 8Al-1Mo-1V. Cyclic state testing of this alloy indicated an absence of stress-corrosion cracking and demonstrated that the time at temperature below the maximum operating temperature of a supersonic aircraft might be an important variable. Exposure tests on brake-formed, stress-relieved titanium 8Al-1Mo-1V sheet specimens indicated a deteriorating effect distinct from stress-corrosion cracking. Fatigue crack growth and fracture toughness determinations indicated no embrittling effects in titanium 8Al-1Mo-1V exposed to hot salt in the absence of stress.

Relative Susceptibility of Titanium Alloys to Hot-salt Stress-corrosion
Relative Susceptibility of Titanium Alloys to Hot-salt Stress-corrosion

Author: Hugh R. Gray

Publisher:

Published: 1971

Total Pages: 68

ISBN-13:

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Susceptibility of titanium alloys to hot-salt stress-corrosion cracking increased as follows: Ti-2Al-11Sn-5Zr-0.2Si(679), Ti-6Al-2Sn-4Zr-2Mo(6242), Ti-6Al-4V(64), Ti-6Al-4V-3Co(643), Ti-8Al-1Mo-1V(811), and Ti-13V-11Cr-3A1(13-11-3). The Ti-5Al-6Sn-2Zr-1Mo-0.25Si(5621S) alloy was both the least and most susceptible depending on heat treatment. Such rankings can be drastically altered by heat-to-heat and processing variations. Residual compressive stresses and cyclic exposures also reduce susceptibility to stress-corrosion. Simulated turbine-engine compressor environmental variables such as air velocity, pressure, dewpoint, salt concentration, and salt deposition temperature have only minor effects. Detection of substantial concentrations of hydrogen in all corroded alloys confirmed the existence of a hydrogen embrittlement mechanism.--P. [i].