Study of fatigue damage in 7010 aluminum alloy

Fracture micromechanisms in overaged 7000 alloy forgings

“…This is in general agreement with what is known about fracture resistance in Al-Zn-Mg-Cu alloys. The formation of voids may occur simultaneously on (Cu,Fe,Mn)Al 3 , Al 7 Cu 2 Fe and Mg 2 Si particles, as already reported by some investigators using the 7000 alloys [3,4,14]. It may, however, be noted that while the Mg 2 Si particles were present in low (<0.147 vol.%) volume fractions in Table 1 Geometrical parameters of the investigated forgings…”

“…Besides, the fracture or decohesion of various IM phase particles depend on the particle morphology and intrinsic mechanical properties. Therefore, the fracture resistance could be strongly affected by the larger particles of Fe-and Si-containing phases, having the lower fracture strength [13,14]. Since the unsoluble Fe-rich phases present in a form of (Cu,Fe,Mn)Al 3 and Al 7 Cu 2 Fe are mostly observed (particles of (Cu,Fe,Mn,Cr)Al 7 , (Fe,Cr,Mn,Cu) 3 SiAl 12 , AlFeCuTi and AlFeSiMgTi phases are rarely found in microstructure of all three alloys), it may be concluded that the particles containing the Fe impurity element play a crucial role in crack initiation and resultant toughness.…”

Notch fracture toughness of high-strength Al alloys

“…The observed changes in roughness are associated with a gradual change in the propagation mechanisms on the microstructure scale. As described by Patton et al [23] and Verma et al [24], crack initiation always occurs in the proximity of the free surface of the specimen and is enhanced by coarse IM particles favorably located ahead of the crack tip. The relative probability of crack initiation increases with the particle fraction and size.…”

Influence of surface treatments on fatigue life of Al 7010 alloy

“…In some cases, inclusions are not exactly at surface but are very close to it, usually at 10 m at its closest point. Patton et al (1998) studied the same alloy and also showed that most of cracks initiated by the fracture of inclusions present in this alloy. Pickling process was found to attack the grain boundaries and inclusions resulting in pits formation on the surface as shown in Fig.…”