Effect of Cold Working on the Properties and Microstructure of Cu-3.5 wt% Ti Alloy

Cu-Ti alloys were strengthened by β’-Cu(4)Ti metastable precipitation during aging. With the extension of the aging time, the β’-Cu(4)Ti metastable phase transformed into the equilibrium β-Cu(4)Ti phase. The Cu-3.5 wt% Ti(Cu-4.6 at% Ti) alloys with different processing were aged at different temperatures for various times after solution treatment at 880 °C for 1 h. The electrical conductivity of samples under different heat treatments had shown an upward trend as time increased during aging, but the hardness reached the peak value and then decreased. The hardness and electrical conductivity of the samples with 70% deformation after aging are higher tha n the samples without deformation. Deformation after aging would cause the metastable phase to dissolve into a matrix. The best combination value of conductivity and hardness is 13.88% IACS and 340.78 Hv, and the optimal heat treatment is 500 °C for 2 h + 70% deformation + 450 °C for 2 h.