| Abstract Scope |
High-strength 7xxx aluminum alloys are widely used in aerospace structures, where high strength, ductility, fracture toughness, fatigue resistance, and corrosion resistance are simultaneously required. Emerging challenges include fatigue crack branching (Kmax-dev) and environmentally assisted cracking (EAC).
Kmax-dev describes an abrupt deviation of fatigue crack propagation from the expected path. EAC, typically evaluated under elevated stress, humidity, and temperature, is associated with hydrogen embrittlement and corrosion-induced degradation.
This study presents methodologies to characterize Kmax-dev and EAC and examines the effects of chemistry and processing using commercially processed plate materials. Variations in Zn, Cu, and Mg content, along with processing conditions, were systematically investigated.
Results show that alloy chemistry and processing strongly influence susceptibility to Kmax-dev and EAC. Precise control of composition and processing is therefore essential to meet stringent performance requirements across strength, fracture, fatigue, and environmental resistance. |