Strengthening of Cu-Ti alloys by stabilization of metastable βʹ phase with addition of Gd element

Strengthening of Cu-Ti alloys with alloying elements is usually accompanied by decreasing of electrical conductivity. Previous study has found that the metastable phase (β′-Cu4Ti) is coherent with Cu matrix which can greatly improve its mechanical performance. In the present work, first-principles calculation was employed to find potential alloying element which can improve the stability of the metastable phase (β′-Cu4Ti); at the same time less amount of Ti atoms remains as solutes in order to maintain moderate electric conductivity. In total effects of 84 alloying elements on β′-Cu4Ti stability were calculated, among which Gd was found to be possible to hinder the β′-Cu4Ti dissolved into matrix. Experiments were carried out to confirm the behavior of Gd as alloying element.