SEDL / STP / STP890-EB / STP33045S

Engineering Property Comparisons of PM and IM Aluminum Alloy Forgings

Wanhill, RJH
Department head and materials engineer, Materials Department, Division of Structures and Materials, National Aerospace Laboratory NLR, Emmeloord, AD

Schra, L
Department head and materials engineer, Materials Department, Division of Structures and Materials, National Aerospace Laboratory NLR, Emmeloord, AD

Pages: 21    Published: Jan 1986

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Abstract

Engineering properties of the aluminum powder metallurgy (PM) alloy 7091-T7E69 and the ingot metallurgy (IM) alloys 7075-T73, 7175-T736, 7010-T736, and 7050-T736 were compared. The properties considered were strength, fracture toughness, fatigue strength, fatigue crack propagation resistance under constant amplitude and spectrum loading, stress-corrosion crack initiation and propagation resistance, and exfoliation corrosion. The PM alloy had a substantially better combination of strength and resistance to stress corrosion and exfoliation and also greater notched fatigue strength at low mean stress levels and long lives. However, its fracture toughness was lower than (in the longitudinal-long transverse orientation) or similar to (in the long transverse-longitudinal orientation) that of the IM alloys, and its resistance to fatigue crack propagation under spectrum loading was greatly inferior. There were only minor differences in properties between the IM alloys.