Improvement of GRCop-84 Through the Addition of Zirconium

GRCop-84 (Cu-8 at.% Cr-4 at.% Nb) has excellent strength, creep resistance, low cycle fatigue (LCF) life and stability at elevated temperatures. It suffers in comparison to many commercially available precipitation-strengthened alloys below 500 C (932 F). It was observed that the addition of Zr consistently improved the mechanical properties of Cu-based alloys especially below 500 C. In an effort to improve the low temperature properties of GRCop-84, 0.35 wt.% Zr was added to the alloy. Limited tensile, creep, and LCF testing was conducted to determine if improvements occur. The results showed some dramatic increases in the tensile and creep properties at the conditions tested with the probability of additional improvements being possible through cold working. LCF testing at room temperature did not show an improvement, but improvements might occur at elevated temperatures.