Optimization of mechanical and antibacterial properties of Ti-3wt%Cu alloy through cold rolling and annealing

Abstract

In this work, a process of cold rolling with 70% thickness reduction and different annealing temperatures was selected to regulate the microstructure of Ti-3wt%Cu alloy. Microstructural evolution, mechanical properties and antibacterial properties of the Ti-3wt%Cu alloy under different conditions were systematically investigated in terms of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), tensile and antibacterial test. The results indicated that cold rolling could dramatically increase the ultimate tensile stress (UTS) from 520 to 928 MPa, but reduce the fracture strain from 15.3% to 3.8%. With the annealing temperature increasing from 400 to 800 °C for 1 h, the UTS decreased from 744 to 506 MPa and the fracture strain increased from12.7% to 24.4%. Moreover, the antibacterial properties of the Ti-3wt%Cu alloy under different conditions showed excellent antibacterial rate ([ 96.69%). The results also indicated that the excellent combination of strength and ductility of the Ti-3wt%Cu alloy with cold rolling and following annealing could be achieved in a trade-off by tuning the size and distribution of Ti 2 Cu phase, which could increase the applicability of the alloy in clinical practice. More importantly, the antibacterial properties maintained a good stability for the Ti-3wt%Cu alloy under different conditions. The excellent combination of mechanical properties and antibacterial properties could make the Ti-3wt%Cu alloy a good candidate for long-term orthopaedic implant application.

Mechanisms of improving the mechanical and antibacterial properties of Ti-3wt.%Cu alloys

“…1 shows the microstructure of Ti-3Cu (S) and Ti-3Cu (700) alloys. The Ti-3Cu (S) was mainly composed of white phases with a laminar morphology (α-Ti + eutectoid Ti2Cu) and light grey phases (α-Ti), which is consistent with the previous results [6].…”

“…It is seen that the subsequent rolling and annealing significantly increased the yield strength and UTS of Ti-3Cu (S) alloy, achieving 553.98 and 683.43 MPa, respectively, while maintaining good fracture strain of 21.55%. Compared with the materials made by casting [3,4,6], the Ti-3Cu (700) alloy delivered superior comprehensive mechanical properties. The strengthening mechanisms rationalize the enhancement in the strength of Ti-3Cu alloys.…”

“…Previous studies have indicated that the antibacterial rate of Ti-Cu alloys fabricated by casting and powder metallurgy (P/M) methods was closely related to Cu contents, and the higher Cu content delivered better antibacterial properties [4,5]. Regrettably, excessive Cu addition would impair plasticity generate cytotoxicity, nausea and diarrhoea [6]. For instance, Aoki et al [7] reported that the elongation of Ti-Cu alloy was only 1% when the copper content was 10 wt.%.…”

Antibacterial Ti–Cu implants: A critical review on mechanisms of action

“…In this regard, two aspects are significant in increasing the antibacterial activity: the increase in surface area fraction of Ti 2 Cu to the total surface of the alloy and the improvement in the homogeneity of this phase in the whole microstructure. Therefore, any processes such as heat treatment, surface treatments, and aging procedures that augment the surface area fraction of Ti 2 Cu exert great influence on the antibacterial properties of the Ti–Cu implant [ 260 , 261 ].…”

Construction of a Rough Surface with Submicron Ti2Cu Particle on Ti-Cu Alloy and Its Effect on the Antibacterial Properties and Cell Biocompatibility

“…Biomedical material is an important branch of materials science as well as an advanced field with rapid development [1,2]. Antibacterial titanium alloys have excellent corrosion resistance, biocompatibility, high specific strength and antimicrobial properties, so they have a good development prospect [3][4][5]. However, antibacterial titanium alloys are still a bioinert material without cellular activity.…”