Evolution and regulation of microstructure and properties of CuCr alloys prepared by self-propagating metallurgy

Abstract

In this paper, the evolution of microstructure and properties of CuCr50 alloy prepared by self-propagating method is analyzed through the synergistic effect of forging and heat treatment. It is found that when the forging ratio is 1.15, the Cr-rich phase in the forged CuCr50 alloy undergoes plastic deformation to a certain extent, the average particle size of the Cr-rich phase is refined from 22.3 μm to 20.5 μm, and the solid solution Cu content in the Cr-rich phase increases. After heat treatment (solid solution + aging treatment) of forged CuCr50 alloy, it is found that the average particle size of Cr-rich phase is further refined to 18.9 μm, and the results of EBSD show that the grains in the bulk Cr-rich phase decrease from 1.85 μm to 0.76 μm, and the lattice orientation of Cr-rich and Cu-rich grains shift to <111> plane. At this time, the second dispersed phase exists in the Cu-rich matrix, and the solid solution of Cu in the Cr-rich phase exists in spherical form. After SHS + forging + heat treatment, the density of CuCr50 alloy increased from 7.51 g cm−3 to 7.98 g cm−3, and the electrical conductivity increased from 12.5 MS m−1 to 18.7 MS m−1. Compared with SHS + heat treatment, the electrical conductivity of CuCr alloy increased by 13.3%. The performance test of 12 kV simulated vacuum interrupter shows that the insulation and breaking properties of the prepared CuCr50 alloy contact material are obviously better than those reported in literature and the requirements of national standard, which provides a theoretical basis for the preparation of high performance CuCr alloy.