Análise de ligas de alumínio aeronáuticas conformadas por jateamento com granalhas - caracterização e previsão de deformação.

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].…”

“…The 7475 aluminum alloy has gained prominence among the 7XXX series due to a high mechanical strength and a high tenacity to fracture (up to 52 MPa.m 1/2 ) [1,3,4,6]. Its basic chemical composition (in weight %) is 5.2 to 6.2% Zn, 1.90 to 2.6% Mg, 1.2 to 1.9% Cu, 0.18 to 0.25% Cr, who is a modified version of 7075 alloy with a reduction of the maximum content of impurities (Fe + Si) from 0.90% to 0.22% by weight [8,9].…”

“…The 7XXX series aluminum alloys are generally subjected to mechanical and thermal processing routes to maximize a certain characteristic. The T7351 route aims to maximize the corrosion resistance in detriment of the mechanical properties through the alloy overaging [3,8]. For the 7475 aluminum alloy, the T7351 consists of a solution heat treatment conducted at temperature of 510 °C, [3,8] a strain relief [4,9], an aging heat treatment at 107 °C during 6 to 8 hours [3,8], and finally an overaging heat treatment, which is performed at 163 °C for 24 to 30 hours [3,8].…”

Efeitos do tratamento térmico de envelhecimento interrompido (T6I4) na tenacidade à fratura da liga de alumínio AA7050

“…Sendo assim, os elementos de liga podem se apresentar como uma segunda fase composta apenas por seus átomos ou como compostos intermetálicos. As partículas de segunda fase são classificadas em: partículas primárias, constituintes, dispersóides e precipitados (BRAGA, 2011).…”

“…Por fim, os precipitados são partículas que apresentam alta solubilidade na matriz de alumínio quando ultrapassam a curva solvus. A existência dos precipitados depende da temperatura de trabalho e, por este motivo, a sua morfologia e composição podem ser controladas por tratamentos térmicos (BRAGA, 2011;ROBSON, 2004).…”