Effect of Deformation Temperature on Microstructure and Mechanical Properties of Low-Alloyed Copper Alloy

The microstructure evolution and mechanical properties of a copper alloy subjected to deformation at temperatures of 20 degrees C and 400 degrees C to total strains from 1 to 4 were examined. The formation of planar low-angle boundaries with moderate misorientations occurs within initial grains at relatively small strains regardless of deformation temperature. Upon further processing the misorientations of these boundaries progressively increase and the new ultrafine grains develop. Continuous dynamic recrystallization takes place during deformation at ambient and elevated temperatures. The kinetics of dynamic recrystallization is discussed in terms of a modified Johnson-Mehl-Avrami-Kolmogorov relationship. The large plastic straining results in significant strengthening, the ultimate tensile strength increases from 190 MPa in the initial state to 440 MPa and to 400 MPa after total strain of 4 at 20 degrees C and 400 degrees C, respectively. A modified Hall-Petch relationship is applied to evaluate the contribution of grain refinement and dislocation density to the overall strengthening.