Structural Characterization of the Rolled and Annealed 7475 Aluminum Alloy

Temperature and annealing time influences on cross-rolled 7475-T7351 aluminum alloy

“…Aluminum alloys are the most used nonferrous metals worldwide due to their several characteristics and advantages [1,2]. Among aluminum alloys, the 7XXX series alloys stand out because the possibility to performing aging heat treatments, due their chemical composition, which make possible to obtain a tensile strength near to 600 MPa [3][4][5][6][7]. They are widely used on aircraft components because they align high tensile strength, good ductility, high corrosion resistance, high fatigue strength and low density [3,4,6].…”

“…There is the formation of "second phase" micro-constituents with the alloy casting and heat treatments on 7XXX series aluminum alloys. They can be divided into three different groups: [3,4,7,[10][11][12] (i) the primary particles (commonly Al 7 Cr, Al 3 Ti e/ou Al 3 Zr) are the first to solidify even before aluminum; (ii) the constituent particles (commonly Al 7 Cu 2 Fe, Al 12 (Fe,Mn) 3 Si, Al 6 (Fe,Mn), Mg 2 Si, SiO 2 , Al 2 CuMg and Al 23 CuFe 4 ), that are usually coherent with the matrix, have a coarse size and can be insoluble or partially soluble; and (iii) the dispersoids (commonly Al 12 Mg 2 Cr and MgZn 2 ) which are commonly smaller than 1 μm.…”

“…[13,14] Similarly, the 7xxx series alloys mechanical strength decreases, for temperatures above 150 ºC, may be associated with the solubilization of the η' dispersoids leading to the formation of MgZn 2 dispersoids, or the coalescing of the η' dispersoid. [13,14] In addition to the T7351 treatment, cold forming processes, such as rolling, can also be used to increase the tensile strength of the 7XXX series aluminum alloys [7,10]. During cold forming processes, important events occur that change the mechanical properties, such as: increase in dislocations density (hardening) and vacancy, change in grain shape which become elongated in the mechanical work direction, and developing crystallographic texture [15][16][17][18][19].…”