Cryogenic Temperature Properties and Secondary Phase Characterization of CuCrZr Composites

We achieved both high electrical conductivity and high mechanical strength in CuCrZr wires, which are comparable to those of Al60 at both 295 K and 77 K. The ultimate tensile strength (UTS) was above 602 MPa at 295 K. The room temperature conductivity was 84% IACS with a residual-resistivity ratio (RRR at 77 K) of 3.57. The wires fabrication included solid solution treatment, aging treatment, and cold drawing. The sequence of the aging and cold drawing after solid solution had not obvious influence on the final UTS and conductivity. At micron scale, the composite wires were composed of a high volume-fraction of Cr-rich secondary phases embedded in Cu matrix. Those Cr-rich particles demonstrated appreciable co-deformation capability with the Cu matrix during cold drawing, which was beneficial significantly to wire fabrication in decreasing the chance of de-cohesion and avoiding cracks during cold deformation. Large amount of Cr precipitates formed after aging, which significantly decreased the Cr content dissolved in Cu matrix, thereby, contributed to the high conductivity in CuCrZr composites.