2020 Volume 59 Issue 1 Pages 105-109
Young’s modulus of a copper single crystal depends heavily on its crystallographic orientation. It is known that the <111> direction with the maximum value shows nearly three times higher Young’s modulus than the <100> direction with the minimum value. In polycrystalline metals of copper and its alloys, the Young’s modulus is closely related to crystallographic texture. Texture control is necessary to increase in a specified direction the properties such as an elastic modulus which does not change greatly by adding alloying elements. In the present study, Cu–30％Zn alloy (brass) was cold rolled to an 85％ reduction in thickness, warm rolled to a 40％ reduction at various temperatures of 573 to 723 K, and finally annealed at 723 K for 1.8 ks to obtain recrystallized microstructure. Adding warm rolling led to a great increase in the Young’s modulus at a direction of 90° to the rolling direction (at the transverse direction, TD) compared to a conventionally cold rolled sheet. The highest value of 122 GPa was achieved for the cold–rolled, warm–rolled at 623 K and annealed sheets. High Young’s moduli at the 90° direction in the annealed sheets are attributed to the recrystallization texture consisting mainly of {011} <322> orientations close to the Brass orientations {011} <211>. It is possible to predict a change in the Young’s modulus at TD with warm rolling temperature from the orientation distribution functions of the annealed sheets. In addition, the mechanism of the {011} <322> recrystallization texture evolution was investigated in the early stages of recrystallization by electron back–scatter diffraction (EBSD) measurements.
