2020 Volume 59 Issue 1 Pages 228-232
The squared resonant frequency and internal friction in commercial copper and copper alloy rolled sheets was measured as a function of temperature, using resonant method. The squared resonant frequency of Oxygen free copper rolled sheet falls when the temperature increases, subsequently rises at around the recrystallization temperature. In the case of brass rolled sheet and iron particle dispersion copper alloy rolled sheet, the squared resonant frequency of these alloys rapidly falls at around the recrystallization temperature. The internal friction curves of these copper rolled sheets consist of background and high peak at around the recrystallization temperature. In the case of the iron particle dispersion copper alloy rolled sheet, the internal friction curve has the small peak at 373K to 473K. The point of inflection of the temperature dependence of squared resonant frequency of these alloys occurs at around these temperatures. An optical length measurement method reveals permanent elongation in the rolled direction and permanent shrinkage in the perpendicular direction to the rolled direction, when the particle dispersion copper alloy rolled sheet is heated at 473K, subsequently is cooled to room temperature. These permanent deformation by heating and cooling affects the temperature dependence of squared resonant frequency.
