Study on segregation solidification and homogenization behavior of Cu-16Sn-0.3Ti alloy powders

Low-segregation Cu-16Sn-0.3Ti alloy is the key raw material for the preparation of Nb3Sn superconducting wires. In this work, the non-segregation Cu-16Sn-0.3Ti alloy powders were successfully prepared by using vacuum induction melting inert gas atomization (VIGA) method and homogenization treatment in vacuum. The segregated solidification behavior of atomized Cu-16Sn-0.3Ti alloy droplets during gas atomization, the interface segregation and atomic diffusion behavior of alloy powders during homogenization were investigated. The results show that the segregated solidification of atomized droplets oc-curs in the form of twinned spherical segment. A critical morphological transition from cellular to dendritic structure occurs when the powder diameter is in the range of 44.1-86.0 mm. With the decreasing of the powder diameter, the lattice distortion in the a phases increases, and the 8 phase volume fraction decreases. Increasing the cooling rate of atomized Cu-16Sn-0.3Ti alloy droplets is an important measure to limit the segregation of Sn. The homogenization condition of 550 degrees C for 96 h is not only conducive to the disso-lution of 8 phases, but also conducive to inhibiting the significant segregation of 8 phases at the powder boundaries. The results provide guidance for the preparation of low -segregation Cu-16Sn-0.3Ti alloys. (c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).