Discontinuous precipitation in a Cu-10Ni-1Si alloy with ultra-high strength, high shock absorption, and good stress relaxation resistance

Abstract

The discontinuous precipitation in a Cu-10Ni-1Si alloy aged at 500 °C and 550 °C was studied to clarify the types of discontinuous precipitates, and the crystal relationships between precipitates and the matrix. The continuous δ-Ni2Si precipitates were detected in the initial aging stage, then discontinuous β-Ni3Si and continuous δ-Ni2Si precipitates were detected simultaneously. The crystal relationship between discontinuous β-Ni3Si precipitates and the copper matrix at the beginning of aging was that: (1̅11̅)Cu//(111̅)β, [011]Cu//[011]β. The lamellar discontinuous β-Ni3Si precipitates significantly improve stress relaxation resistance and damping properties, which are attributed to the interaction between lamellar structure and dislocation motion. These findings indicated that the formation of the lamellar discontinuous precipitates tends to prevent dislocation slip and promote precipitation, resulting in enhanced mechanical properties and conductivity properties simultaneously.