CALPHAD-guided alloy design of Cu-Pb-(X) immiscible alloy with rodlike secondary phases

Novel Cu-24Pb-xAl alloys with dispersed and rodlike Pb-rich secondary phases (PSPs) were designed and prepared with the guidance of CALPHAD. Through primary binary-phase diagram analysis and thermodynamic calculation, Al was proven to be a suitable alloying element in Cu-Pb system to promote the formation of dispersed and rodlike PSPs during solidification by introducing a (L-1 +L- (2 )+( )alpha-Cu) phase region in Cu-Pb-xAl systems. The Cu-24Pb-xAl (wt-%, x = 0, 2, 4) alloys were then prepared in order to verify the reliability of the alloy design strategy. Cu-24Pb-2Al alloy with rodlike PSPs was successfully designed and prepared. A novel strategy to design Cu-Pb-(X) immiscible alloy with optimised microstructure is thus proposed in this work which can help establish a design criterion for other immiscible alloys.

Automated summary

Novel Cu-24Pb-xAl alloys with dispersed and rodlike Pb-rich secondary phases (PSPs) were successfully designed and prepared with the guidance of CALPHAD. The addition of Al was proven to promote the formation of dispersed and rodlike PSPs in Cu-Pb system, leading to the successful design of Cu-24Pb-2Al alloy. This work proposes a new strategy to design immiscible alloys with optimized microstructure, establishing a design criterion for other immiscible alloys.