Investigation into crack initiation from corrosion pit in 7075-T6 under ambient laboratory and saltwater environments. (January 2015)

• Record Type: Journal Article
• Authors: Sabelkin, V.; Perel, V.Y.; Misak, H.E.; Hunt, E.M.; Mall, S.
• Is Part Of: Engineering fracture mechanics. Volume 134(2015)
• Page Start: 111
• Page End: 123
• Publication Date: 2015-01
• Subjects: Crack initiation -- Corrosion pit -- Aluminum alloy -- Finite element analysis -- Saltwater environment; Fracture mechanics -- Periodicals; Rupture, Mécanique de la -- Périodiques; Fracture mechanics; Periodicals; 620.112605
• DOI: 10.1016/j.engfracmech.2014.12.016
• Languages: English
• ISSNs: 0013-7944

Abstract

Highlights: Characterized experimentally transition of a corrosion pit to a crack under fatigue. Two types of corrosion pit (through and corner) at the hole were studied. Transition of pit to crack was studied in two environments (ambient and salt water). 2- and 3-dim finite element analyses were used to compute stress intensity factors. Stress intensity factor vs crack initiation cycle relations were analyzed & compared. Abstract: Transition of corrosion pit to crack was studied. Fatigue cycles to initiate 250 μm crack from two corrosion pit configurations under ambient laboratory and saltwater environments were correlated with stress intensity factor range (Δ KI ) and applied stress range. Stress to initiate crack from through-pit was less than from corner-pit in both environments. Δ KI to initiate crack from corner-pit was less than from through-pit in both environments. However, stress or Δ KI to initiate crack was less in saltwater than ambient environment for both pit configurations. Fatigue damage mechanism was similar in both pit configurations and under both test environments.