Modulation of microstructure and properties of Cu−Ni−Sn alloy by addition of trace Ti

The segregation of Sn and discontinuous precipitation at grain boundaries are detrimental to the strength, ductility, and machinability of the Cu−Ni−Sn alloy. A strategy to solve the above problems is multi-component composition design by introducing strong enthalpic interaction element. In this work, a series of Cu₈₀Ni₁₅Sn_5−xTi_x (at.%) alloys were designed by cluster-plus-glue-atom model, and the effects of Ti content on the microstructure and properties of the alloys were systematically investigated using TEM and other analysis methods. The results demonstrate that Ti can effectively inhibit the segregation and discontinuous precipitation while promoting continuous precipitation to improve the high-temperature stability of the alloys. As the Ti content increases, the distribution of Ti changes from uniform distribution to predominant precipitation. The hardness and conductivity of the alloy exceed those of the C72900 (Cu−15Ni−8Sn (wt.%)) commercial alloy and the Cu₈₀Ni₁₅Sn₅ (at.%) reference alloy when Ti is in the solution state.