The effects of the inter-annealing process on the microstructure, plane
stress fracture toughness, and tensile properties of an AA7075 cladding sheet
were investigated using optical microscopy, scanning electron microscopy,
electron backscattered diffraction, transmission electron microscopy, and
mechanical property tests. The results indicate that the plane stress fracture
toughness of AA7075-T6 cladding sheet can be greatly improved. The plane stress
fracture toughness for the longitudinal−transverse (L−T) and
transverse−longitudinal (T−L) directions were 117.7 and 94.8 MPa·m1/2,
respectively, after intermediate annealing at 380 °C. This represents an
increase of 23.9 MPa·m1/2 in the L−T direction and
22.6 MPa·m1/2 in the T−L direction compared with the AA7075-T6
cladding sheet without intermediate annealing. Moreover, the tensile strength
remains similar under different conditions. Microstructure analysis indicates
that intermediate annealing before heat treatment can result in long
sub-grains, few recrystallized grain boundaries, and small size precipitates in
AA7075-T6 cladding sheets.
Fang YU, Ling-fei YANG, Zhong-chao ZHAO, Xiang-jie WANG, Cheng-cheng CHEN, Jian-zhong CUI
. Effect of annealing process on microstructure and plane stress fracture
toughness of 7075 cladding sheet[J]. Transactions of Nonferrous Metals Society of China, 2025
, 35(11)
: 3650
-3661
.
DOI: 10.1016/S1003-6326(25)66904-4