Cu–Ni–Sn–Si alloys designed by cluster-plus-glue-atom model

Segregation in the solidification process and discontinuous precipitation during aging cause the service and processing performance of Cu–Ni–Sn alloys deteriorating severely. In this work, Si is added as a fourth element for the design of Cu80Ni15Sn5−xSix (x = 0, 0.625, 1.25, 1.875, 2.5) series alloys using cluster-plus-glue-atom model to solve these issues from the point of composition design. The results suggest that the introduction of Si leads to the disappearance of the lamellar structure formed in the as-cast alloys while also inhibiting discontinuous precipitation during aging. The solidus–liquidus temperature range is reduced with the addition of Si, and this strategy is most effective when the Si is in the solution state. With increasing Si content, the high-temperature conductive stability of the alloys is improved. Moreover, the hardness and conductivity of the Cu80Ni15Sn5 alloy designed by cluster-plus-glue-atom model are improved compared with those of C72900 (Cu78.96Ni16.65Sn4.39) commercial alloy, and the properties of Cu80Ni15Sn4.375Si0.625 alloy are basically equivalent to those of C72900 alloy. These findings indicate that alloys with excellent synthetic properties can be produced as long as the content and existential state of Si are reasonably controlled. [Display omitted] •The precipitate clusters of Cu-Ni-Sn alloy are interpreted for the first time.•A series of Cu-Ni-Sn (Si) alloys are designed by the cluster-plus-glue-atom model.•The existential state of Si in the alloy is confirmed.•The new Cu80Ni15Sn4.375Si0.625 alloy with excellent synthetic properties is obtained.