On the variability in static and cyclic mechanical properties of extruded 7075‐T6 aluminum alloy

Abstract

The present paper investigates the variability in the static and cyclic properties of two nominally identical supplies of the aeronautical Al grade 7075-T6. Samples were extracted from extruded bars of 15 and 60 mm diameter and with slightly different chemical composition. Noticeable differences were found in tensile strength, total elongation, and low-and high-cycle fatigue strength, despite the nearly identical hardness value. The diverse mechanical behavior has been imputed to different extrusion ratio and therefore work hardening along with a more or less fine distribution of precipitates and dispersoids. The high-cycle fatigue strength was found to be in direct correlation with the monotonic yield strength and the size of the largest intermetallic precipitate. A simple equation based on Murakami sqrt (area) parameter is proposed to predict the fatigue endurance. Tensile tests and microstructural analyses are recommended instead of conventional hardness tests to have a tighter quality control on the mechanical properties of semifinished products.

Initiation and growth of fatigue cracks in sheets with U-shaped notches in the first and mixed modes of fracture

“…According to the given data in reference [31], the final fracture stress is about 663 MPa, percentage of the cross-section reduction is 15%, and the Poisson's ratio will be 0.33.…”

Local Ratcheting at the Notch Region of Non-Press-Fitted and Press-Fitted Al 7075-T6 Samples Undergoing Asymmetric Stress Cycles

“…Figure 5 presents the yield surface translation based on the A-V hardening rule for different testing materials with DIFs of 0, 1%, and 2%. This figure includes stress-strain curves developed by the Ramberg-Osgood equation [30], at which materials constants for Al7075-T6 are taken from [34]. The yield translation in Figure 5c is presented for the plane stress condition and in a two-dimensional coordinate σ 1 − σ 2 system.…”

The anisotropic fatigue properties of extruded Al–Zn–Mg–Cu alloy

“…Wei [16] studied the anisotropy of the mechanical properties of 7050 alloy sheets in different directions, and its anisotropy is mainly affected by recrystallisation. Benedetti et al [17] found that there were noticeable differences in tensile strength, total elongation and low- and high-cycle fatigue strength for 7075-T6 extruded bars with nearly identical hardness. He also proposed an equation relating the yield stress and the size of the maximum intermetallic precipitate to predict the fatigue endurance.…”