Influence of Ti Content on Microstructure and Properties of Low-Nickel Copper Alloys

Cu-2.8Ni-1.1Fe-0.9Mn-xTi low-nickel copper alloys with different contents of Ti (x=0～1.79%, mass) were prepared by vacuum induction melting. The effects of Ti content on microstructure, mechanical properties and corrosion resistance in simulated seawater of the copper alloy were studied by microstructure observation, tensile testing and corrosion testing. The results show that the grain size decreased obviously, and the small and dispersed phases precipitated with adding element Ti in the low-nickel copper alloy; the precipitation phases increased with increasing the Ti content; besides the small and dispersed phases, massive phases appeared in the copper alloy with 1.79% Ti added. The tensile strength and hardness of the low-nickel copper alloy improved gradually and the plasticity slightly decreased with the increase of Ti content. The corrosion rates of the copper alloys with Ti in simulated seawater first decreased and then increased with the increase of Ti content, but all of them were lower than that of the copper alloy without Ti. The copper alloy with 0.88% Ti has the lowest corrosion rate, 14.486 6 mg·m-2·h-1.