SEDL / STP / STP397-EB / STP46426S

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

Piper, D. E.
Research engineers, The Boeing Co., Seattle, Wash.

Fager, D. N.
Research engineers, The Boeing Co., Seattle, Wash.

Pages: 22    Published: Jan 1966

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Abstract

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.