Abstract
Deformation behavior of Cr phase in Cu–15Cr based in situ composites during cold deformation has been examined. Deformation strain partitioning between Cu and Cr phases after cold drawing occurs because the Cr phase tends to elongate less than Cu phase due to its higher flow stress and modulus. The deformation process of Cr phase during cold drawing comprises slight, steady and slow deforming stages, and the Cr phase is primarily deformed in the second stage. At a given drawing strain, the deformation strain of Cr phase increases with increasing hardness ratio of Cu phase to Cr phase, therefore, the finer drawing structure (with smaller interphase spacing and Cr thickness) will be obtained with either increasing hardness of Cu phase or reducing hardness of Cr. Hardening of Cr phase by the addition of alloying elements affects the strength of Cu–15Cr based in situ composites in two opposite ways-increasing the second phase strengthening and reducing the structural refinement strengthening, the latter is more prominent at higher drawing strain. The strength improvement of the as cold drawn Cu–15Cr based in situ composites can be achieved by increasing hardness ratio of Cu to Cr through either softening of the Cr phase or hardening of the Cu phase.
