Crack tip closure and environmental crack propagation

✍ Scribed by O. Buck; J.D. Frandsen; H.L. Marcus

• Book ID: 103067496
• Publisher: Elsevier Science
• Year: 1975
• Tongue: English
• Weight: 616 KB
• Volume: 7
• Category: Article
• ISSN: 0013-7944
• DOI: 10.1016/0013-7944(75)90072-7

✦ Synopsis

AMraet

-Crack propagation rate, da/dN, and crack tip closure stress, o.., in part-through crack fatigue specimens of ahuninum alloys are drastically affected by gaseous environments. The present studies indicate that the crack closure reflects the influence of the environment on the plastic deformation at the crack tip, and, therefore, on the crack propagation rates. Postulating that da;dN is mainly determined by AKa 01 (crnu-uW) (instead of AK = (a,, -o,,,,.), as is done traditionally) leads to the relationship do/dN = A(AK.,$ in which A and n are vhtuahy independent of the gaseous environment. The exponents are n -3.3 for Al 7075 T651 and n -3.1 for Al 2024 T351. respectively.