A statistical study of the effects of processing upon the creep properties of GRCop-84

Reusable launch vehicles require main combustion chamber liner materials that can withstand elevated temperatures and high stresses without creeping. GRCop-84 (Cu–8 at% Cr–4 at% Nb) was developed to meet this need. The Cr2Nb precipitates formed in the alloy strengthen the Cu matrix by impeding dislocation motion and inhibiting grain growth. GRCop-84 has been produced in a variety of forms, each with a unique processing history. The creep properties of the various forms were compared, and results demonstrated that processing had a statistically significant, quantifiable effect upon the creep properties of GRCop-84. The differences in creep properties could largely be explained by texture, testing environment and scatter of the test results. Even with the statistical differences, GRCop-84 did not show grossly different creep results as a function of processing, indicating that any of the processing methods would be suitable for producing a rocket engine liner.