Micro-mechanism of texture evolution during isochronal annealing of as-annealed hot rolled Al-Cu-Mg sheet

Abstract

Texture evolution of as-annealed hot rolled Al-Cu-Mg sheets with initial R-Cube {001}〈110〉, R-Cu {112} 〈110〉, and m-Brass {211}〈0,−1,1〉 texture has been studied by X-ray diffraction. Continuous overall texture intensity weakening effect and micro-mechanism, during the isochronal annealing at 280–480 °C for 2 h, was investigated using electron backscatter diffraction and scanning electron micrograph. A new texture fibre {φ1 = 0° − 90°, φ = 65°, φ2 = 63°} has been found. The results show that obvious overall texture intensity weakening started at 400 °C. The texture intensity ratio can be used to depict such weakening trend. Moreover, the overall texture intensity was determined by the reduction of R-Cube at 400–420 °C, but related to the decomposition of Brass at 420–480 °C. Such decomposition of Brass and induced rebound of orientations on the m-fibre, as well as R-Cu texture, due to the near 30°〈111〉 relationship, led to the further overall texture weakening and severe randomization. Keywords: Aluminium alloy, R-Cube, M-fibre, Texture intensity ratio