Metallurgical Studies on Cracked Al–5.5Zn–2.5Mg–1.5Cu Aluminum Alloy Injector Disc of Turbine Rotor
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The high-strength aluminum alloy Al–5.5Zn–2.5Mg–1.5Cu (AA 7075) is extensively used in aerospace applications. An injector body of a gas generator for a turbine rotor in a liquid propulsion system was fabricated out of AA 7075 forgings in the T7352 condition, and, subsequent to a qualification hot test, one of the injector discs showed the presence of cracks on the top face of the body. Detailed metallurgical investigation indicated that the failure was caused by stress-corrosion cracking (SCC).
KeywordsStress-corrosion cracking AA 7075 aluminum alloy
The authors express their sincere thanks to Shri M.C. Mittal, Group Director, Materials and Metallurgy Group, VSSC, and Dr. K.N. Ninan, Deputy Director, VSSC, for their guidance and encouragement during the work. They are indebted to Dr. B.N. Suresh, Director, VSSC, Trivandrum for his permission to publish this work.
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