SEARCH · Engineering Papers
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Mercury corrosion and evaluation of corrosion products found in separators of three chromium molybdenum alloy boiling thermal convection loops
Stress corrosion of high strength aluminum alloy in NaCl solution, separating corrosion and stress effects
Corrosion and stress effects separation in stress corrosion of Al-Zn-Mg-Cu alloy, considering machined surface finishing role
Stress corrosion testing method to separate corrosion and stress effects applied to Al and Ti alloys
The problems encountered and the methods used to prevent corrosion and stress corrosion cracking on current space vehicles and aircraft are discussed. Preventing these problems on the Space Shuttle, in particular, by properly using materials that are highly resistant to this phenomenon, is examined in detail.
Candidate alloys for the Shuttle Solid Rocket Booster (SRB) case were tested under simulated service conditions to define subcritical flaw growth behavior under both sustained and cyclic loading conditions. The materials evaluated were D6AC and 18 Ni maraging steel, both heat treated to a nominal yield strength of 1380 MN/sq m (200 ksi). The sustained load tests were conducted by exposing precracked, stressed specimens of both alloys to alternate immersion in synthetic sea water. It was found that the corrosion and stress corrosion resistance of the 18 Ni maraging steel were superior to that of the D6AC steel under these test conditions. It was also found that austenitizing temperature had little influence on the threshold stress intensity of the D6AC. The cyclic tests were conducted by subjecting precracked surface-flawed specimens of both alloys to repeated load/thermal/environmental profiles which were selected to simulate the SRB missions. It was found that linear removal operations that involve heating to 589 K (600 F) cause a decrease in cyclic life of D6AC steel relative to those tests conducted with no thermal cycling.
The effect of corrosion on the tensile properties of duralumin while stressed is shown in graphical form. According to the test results, duralumin sheet, coated with aluminum, maintains its initial properties unimpaired for corrosion periods as long as 60 days with an applied tensile stress as high as 20,000 lb/sq.in., which is approximately one-half the stress corresponding to the yield point as defined here. In these tests, that material which had been heat-treated by being quenched in cold water, though far inferior to similar material having the aluminum coating, was superior to the sheet material which was heat treated by being quenched in hot water. These results are in excellent agreement with the results of previous laboratory and exposure tests.
As a result of testing, it was determined that control of the rate of quenching and the avoidance of accelerated aging by heating are the only means of modifying duralumin itself so as to minimize the intercrystalline form of corrosive attack. It is so simple a means that it should be adopted even though it may not completely prevent, but only reduce, this form of corrosive attack. By so doing, the need for protection of the surface is less urgent.
Separation of gaseous, liquid, and solid reaction products of hot salt stress corrosion cracking of titanium
Separation of gaseous, liquid and solid reaction products generated by hot salt corrosion of titanium, noting gas diffusion effect on cracking
External loading procedures for stress corrosion tests of aluminum alloys, and ferrous and nickel alloys
Material corrosion control techniques, considering initial structure design, coatings application and protective coatings specifications
The Conference Proceedings contains 31 papers presented at the Propulsion and Energetics Panel Symposium on Erosion, Corrosion and Foreign Object Damage Effects in Gas Turbines which was held from 25-28th April 1994, in Rotterdam, The Netherlands. The Technical Evaluation Report and the Keynote Address are included at the beginning and discussions follow most papers. The Symposium was arranged in the following Sessions: Operational Experience and Requirements (7); Deposition and Erosion (7); Foreign Object Damage (5); Coatings, Repairs and Materials Aspects - 1 (4); Coatings, Repairs and Materials Aspects - 2 (7); and Testing and Certification Procedures (1).
Explore the source record for details and available documents.
Stress corrosion cracking of titanium alloys and chloride absorption during formation of titanium oxide
Mechanical and electrochemical factors involved in stress corrosion of aluminum alloys
Electrochemistry of freshly generated titanium surfaces and stress corrosion cracking in aqueous solutions and in molten salts
The spectra of the pure metals tested and their oxides were used to analyze the patterns obtained for various superalloys. The quantitative results for two superalloys revealed differences between the surface compositions and their behavior under different conditions of oxidation. The following results occurred during the hot corrosion of samples in the presence of Na2So4: a lack of Ti migration; strong effects on Cr; and, a higher speed of alteration of superalloys.