Mechanical properties and the structure of chromium–zirconium bronze after dynamic channel-angular pressing and subsequent aging

Abstract

Changes in the structure and mechanical properties of the low-alloy chromium–zirconium bronze Cu–0.14% Cr–0.04% Zr have been investigated after a high-strain-rate (10⁴–10⁵ s^–1) deformation by the method of dynamic channel-angular pressing (DCAP) and following annealings at 300–700°C. A significant increase in the mechanical properties of the investigated bronze after DCAP and after DCAP and subsequent aging at temperatures of 400–450°C has been established. Thus, compared to the initial quenched state the ultimate tensile strength increases by a factor of 2.6 and 2.8 and the yield stress, by a factor of 3.3 and 5.1, respectively, with the retention of satisfactory plasticity. It has been shown that, upon DCAP and subsequent annealings, in the low-alloyed bronze under investigation there occurs a decomposition of the α solid solution with the precipitation of nanosized particles. This leads to a significant strengthening of the bronze and to an increase in its thermal stability compared with the pure copper subjected to DCAP.