High strength, high conductivity and good softening resistance Cu-Fe-Ti alloy

Cu alloys with high strength, high electrical conductivity (EC) and good softening resistance (SR) are urgently needed in many fields. A Cu-1.06 wt% Fe-0.44 wt% Ti alloy was designed concerning the calculation of phase diagrams. It was expected that the Fe2Ti phases could precipitate to obtain high performance. The designed alloy was prepared and it obtained the most excellent properties of 211 HV hardness, 542 MPa tensile strength, 9.8% uniform elongation, 79% IACS EC and 575 °C softening temperature after solid solution, cold rolling (90% reduction of thickness) and aging at 450 °C for 24 h. The Fe2Ti phases indeed precipitated in the Cu matrix, which proved the alloy design idea. The precipitation kinetics, interaction between recrystallization and precipitation, and the effects of precipitation on strength, EC and SR were discussed. It was concluded that the precipitation driving force of the Fe2Ti phase itself in Cu was weak, and the cold rolling could significantly promote the precipitation. The precipitation of Fe2Ti slowed down the recrystallization to a certain extent. The high strength and high EC were mainly due to the precipitation strengthening and purification effects of the Fe2Ti precipitation on the Cu matrix. Besides, the good SR was mainly due to the low diffusion rate of Fe in Cu and the weak precipitation driving force of Fe2Ti. [Display omitted] •A novel Cu-Fe-Ti alloy was designed based on the CALPHAD and tie line principle.•Tensile strength of 542 MPa and electrical conductivity of 79% IACS were obtained.•The softening temperature of the alloy is as high as 575 °C.•The strengthening, conductive and anti-softening mechanisms were studied.