Defect analysis of the Cu-Cr-Zr-Nb alloys prepared by the non-vacuum melting process

Abstract

The microstructure and properties of the Cu-Cr-Zr-Nb alloys prepared by non-vacuum melting and vacuum melting were compared and analyzed in this paper. The results showed that, compared with vacuum melting, the alloy prepared by non-vacuum melting had a more uneven microstructure and a coarser grain. In the meantime, the alloy prepared by non-vacuum melting stored less energy and had a lower proportion of HAGBs (high-angle grain boundaries), and the texture distribution along the TD and RD directions was not uniform. In terms of properties, the hardness and electrical conductivity of the Cu-Cr-Zr-Nb alloys prepared by non-vacuum melting were lower than those of the alloys prepared by vacuum melting. The electrical conductivity of the non-vacuum melting alloy was only 70.8 %IACS (International Annealed Copper Standard), and the average hardness fluctuated greatly. However, the electrical conductivity of the alloy prepared by vacuum melting could reach 81.0 %IACS, and the hardness was very uniform. Further research indicated that there were cracks and inclusions in the alloy prepared by non-vacuum melting. A large number of ZrO2 inclusions were found along the grain boundary, which demonstrated that the oxide inclusion was the primary cause of the crack formation. On this basis, three important suggestions for the preparation of the Cu-Cr-Zr-Nb alloys by non-vacuum melting were put forward to reduce the cost and improve the properties of the alloys. It provided guidance for developing high-performance Cu-Cr-Zr-Nb alloys by non-vacuum melting.