Effect of Fe content on low cycle fatigue behavior of squeeze cast Al-Zn-Mg-Cu alloys

Modification Mechanism and Uniaxial Fatigue Performances of A356.2 Alloy Treated by Al-Sr-La Composite Refinement-Modification Agent

“…Generally, S-N curve is used to describe fatigue behavior of alloys under stress control, and it is usually expressed by Basquin's equation which can reflect the trend of fatigue life with stress amplitude [6][7][8]:…”

“…Under higher cyclic stress amplitudes, fatigue life of the alloy is short, and the density of dislocations in the matrix is low. Some dislocations cannot cross grain boundaries, leading to cyclic hardening of alloys [6]. However, when dislocations build up to a certain level, dislocation arrays will form by Fig.…”

“…Due to its excellent overall performances and low cost, A356.2 alloy has been widely used in many engineering structural components such as automotive wheels, engine mounts, steering knuckles and so on [3][4][5], where repeated alternating loads during service and fatigue failure of the alloys should not be ignored. Statistics results showed fatigue causes about 80% fractures of Al alloy structural components in recent decades, with sudden fractures accounting for most of them, causing huge economic losses [6][7][8].…”

Effect of ultrasonic melt processing and Al-Ti-B on the microstructural refinement of recycled Al alloys

“…However, due to the various sources of Al scraps and use of iron-based tools, these impurity elements, such as, Fe and Si, are easily introduced to the recycled Al alloys [6] , [7] , [8] , [9] . Fe is the main impurity element in Al-Cu alloys, that form hard and brittle plate-like Fe-rich intermetallic phases (named Fe-rich phases hereinafter) during solidification [10] , [11] , [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] , [25] , [26] , [27] , [28] , [29] . The type of Fe-rich phases in Al-Cu alloys, such as, Al 3 (CuFe), Al 6 (CuFe), Al 7 Cu 2 Fe (β-Fe), Al 15 Fe 3 (SiCu) 2 (α-Fe), varies with different alloy compositions, cooling rates, and external fields during solidification [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] .…”

“…The type of Fe-rich phases in Al-Cu alloys, such as, Al 3 (CuFe), Al 6 (CuFe), Al 7 Cu 2 Fe (β-Fe), Al 15 Fe 3 (SiCu) 2 (α-Fe), varies with different alloy compositions, cooling rates, and external fields during solidification [12] , [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] . The presence of these brittle particles (especially the large sizes) in the alloys significantly decreases the fatigue strength and ductility of the alloys [10] , [11] , [12] , [13] , [14] . In order to avoid these problems and foster the use of these recycled Al alloys, various methods are used: 1) The chemical route to change the morphology of Fe-rich particles by adding trace elements or grain refiner before solidification [15] , [16] , [17] , [18] , [19] , [20] , [21] ; 2) applying ultrasonic or electromagnetic fields to refine the microstructure during solidification [22] , [23] , [24] , [25] ; 3) using heat treatments or thermomechanical processing, such as rolling or extrusion, to broke the Fe-rich particles after solidification [26] , [27] , [28] , [29] .…”