Excellent synergies of mechanical properties and biological performance of additively-manufactured Ti-Cu - Cu alloy

Insufficient combination of mechanical properties and biological performance has hindered the application expansion of Ti-Cu - Cu alloy in biomedical field. In this study, Ti-13Cu-1Al alloy was prepared by additive manufacturing technology, and the microstructure and properties of the alloy were regulated by post-heat treatment. The strengthening-toughening mechanisms and biological performance enhancing mechanisms were comprehensively revealed by investigating the microstructure and properties of the alloy. The results show that, although the as-deposited alloy has a homogeneous microstructure and fine precipitated phases, the higher residual stresses in the alloy make it poorly ductile. After annealing in the biphasic region, due to the processes of precipitated phases spheroidization, elimination of small defects and residual stresses, reduction of hard phases' volume fraction, and orientation alteration of the alpha-Ti matrix, the elongation of the alloy increases significantly up to 18%. After annealing in the beta-phase region, the morphology of Ti2Cu 2 Cu phases changed from blocky to lath, which effectively hinder dislocation motion and leads to a significant increase in the tensile strength, up to a maximum of 1025 MPa. Meanwhile, the alloy also has good plasticity due to the rich slip pattern of dislocations in alpha-Ti matrix, achieving a good balance of strength and plasticity. In addition, both the as-deposited and annealed alloy show strong bacterial inhibition and good biocompatibility comparing to as-cast alloy, indicating excellent synergies of mechanical and biological properties are achieved for the additively-manufactured alloy.