Evolution of microstructure and properties of AA 7072/7075/7072 composite sheets during various finish rolling temperature

In this present study, AA 7072/7075/7072 composite sheets with different finish rolling temperatures (210–350 °C) were prepared by the muti-pass hot finish rolling process. Effects of final rolling temperature on microstructure and properties of AA 7072/7075/7072 composite sheets were investigated after aging (AA 7075-T6 composite) via optical microscopy (OM), scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and transmission electron microscope (TEM). It was found that bendability of AA 7075-T6 composite alloy is highly dependent on finish rolling temperature. The results show that when increasing the finish rolling temperature, the tensile properties of 7075 hot rolled (7075-F) decreases, while tensile properties of 7075 annealed (7075-O) composites sheets increase. With excessive finish rolling temperature (280 °C and above), grain is not uniform along the thickness direction and texture was dominated by Goss texture. Bending test results show that break occurred for AA7075-T6 composite sheet when the finish rolling temperature was 280 °C and above. Texture and inhomogeneous coarse grain propagate formation of crack and degenerate bendability of the alloy.