Distinct fatigue limit of a 6XXX series aluminum alloy in relation to crack tip strain-aging

Welding of AA6061-T6 Sheets Using High-Strength 4xxx Fillers: Effect of Mg on Mechanical and Fatigue Properties

“…This produced cyclic slip resistance at the crack tip and retarded crack growth. Moreover, solute Mg can shift crack motion to a non-localized mode because a large number of slip systems are activated, leading to a longer crack path and longer fatigue life before the final failure [ 8 , 13 ]. Because of the higher Mg content in the novel filler wires, the FZ of the FMg0.6 and FMg1.4 joints contained significantly more solute Mg than that of the ER4043 joint [ 22 ].…”

“…The fatigue properties of aluminum alloy joints play an important role in the safety and reliability of structural assemblies [ 6 ], with up to 90% of engineering constructions failing because of fatigue [ 7 ]. Researchers have found that excess solute Mg can improve the fatigue strength and fatigue life of 6xxx alloys [ 8 , 9 , 10 , 11 , 12 ]. Takahashi [ 9 ] reported that the fatigue strength and fatigue life of 6xxx alloys can be improved by adding excess Mg, so that Mg exists in solid solution in the matrix.…”

“…The authors added 0.5 and 0.8 wt.% excess Mg to an AA6061-T6 alloy with a stoichiometric Mg 2 Si composition, and found that the excess Mg increased the work hardening and produced cyclic slip resistance against crack growth. In addition, the excess solute Mg caused dynamic strain aging, which reduced the propagation rate of fatigue cracks by slowing the motion of mobile dislocations [ 8 , 9 ].…”

Effects of aging state on fatigue properties of 6A01 aluminum alloy

“…Additionally, 6XXX series Al alloys have been widely used in structural body parts because of their low density, medium strength, good-forming ability, and excellent welding performance. [1][2][3][4][5] However, fatigue cracks usually occur in the Al alloy components because of the alternating load during long-term service. [6][7][8][9][10][11][12] It is estimated that 80% to 90% of the engineering component failures may result from a fatigue fracture.…”

“…Low weight and high strength are the main basis for the selection of materials for high‐speed trains. Additionally, 6XXX series Al alloys have been widely used in structural body parts because of their low density, medium strength, good‐forming ability, and excellent welding performance 1–5 . However, fatigue cracks usually occur in the Al alloy components because of the alternating load during long‐term service 6–12 .…”