Tailoring Cu nano Bi self-lubricating alloy material by shift-speed ball milling flake powder metallurgy

Abstract

A novel method for preparing lead-free Cu nano Bi (CNB) alloy materials by nano Bi powder and shift-speed ball milling (SSBM) flake powder metallurgy was proposed. To improve the mechanical and tribological properties of the alloy materials, the spherical CuSn10 powder was firstly extruded and sheared into flakes by low-speed ball milling (LSBM) in the SSBM system. Meanwhile, the nano Bi powder was evenly dispersed and coated on the CuSn10 flakes. The mechanical alloying between mixed powders and the cold welding of flake CuSn10 flakes containing nano Bi into layered particles were then realized through short-time high-speed ball milling (HSBM) in the SSBM system. While promoting the uniform dispersion of lubricating phase Bi, the surface area of matrix CuSn10 flake was increased so as to achieve better combination of CuSn10 matrix in the material. Results show that the mechanical properties of the CNB material prepared through nano Bi powder and SSBM flake powder metallurgy improved compared with the Cu-Bi material prepared by HSBM. In addition, the antifriction and wear resistance improved by 30% and 80%, respectively.