Speaker
Description
Abstract: A special necking morphology was observed on Cu-Nb composites after the thermal compression. During the compression process under the heating temperature above 700℃, the nanofibers recrystallized rapidly, and the properties of Cu-Nb composites rapidly attenuated in the dynamic instabilty, and it was difficult to observe the rheological area. During the compression process below 700℃, the strain rate increased at first and reached the peak value, then rapidly dropped. The flow stress was tended to be stable, and the dynamic equilibrium was stable by the dislocation adjustment. Based on the modified Arrhenius-type hyperbolic sine constitutive model, the thermal compression constitutive relationship of Cu-Nb material was established, and the overlap between model calculation and experimental data was higher than 90%. The dynamic material model (DMM) was adopted, and the thermal processing maps of Cu-Nb composites with the strain of 0.2 and the strain of 0.6 were plotted. Based on these maps, materials with the strain of 0.6 prefers to a higher strain rate in the 620℃-750℃ region. However, lower strain rate was beneficial to a better deformability and good hot workability in the 650℃-730℃ region with the strain of 0.2.
Keywords: Pulse magnet, Cu-Nb composites, thermal deformation, constitutive relationship, thermal processing map
