Antibacterial Titanium Produced Using Selective Laser Melting ANDREW MACPHERSON, 1 XIAOPENG LI, 2 PAUL McCORMICK, 1 LING REN, 3 KE YANG, 3 and TIMOTHY B. SERCOMBE 1,4 1.—School of Mechanical and Chemical Engineering, The University of Western Australia, Crawley, Australia. 2.—School of Mechanical and Manufacturing Engineering, The University of New South Wales, Sydney, Australia. 3.—Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China. 4.—e-mail: tim.sercombe@uwa.edu.au Titanium and titanium alloys used in current medical and dental applications do not possess antibacterial properties, and therefore, postoperative infection remains a significant risk. Recently, the addition of silver and copper to con- ventional biomaterials has been shown to produce a material with good antibacterial properties. In this article, we investigate selective laser melting as a method of producing antibacterial Ti-6Al-4V containing elemental addi- tions of Cu or Ag. The addition of Ag had no effect on the microstructure or strength, but it did result in a 300% increase in the ductility of the alloy. In contrast, the addition of Cu resulted in an increase in strength but in a de- crease in ductility, along with a change in the structure of the material. The Cu-containing alloy also showed moderate antibacterial properties and was superior to the Ag-containing alloy. INTRODUCTION Advanced additive manufacturing technologies such as selective laser melting (SLM) are having an increasingly important role in the production of customized medical devices. The ability to produce highly complex features such as specifically designed porosity and the ability to make two parts slightly differently in geometry for almost no cost penalty are some of the key advantages of the processes. Typi- cally, parts for orthopedic applications are made from Ti-6Al-4V, 1–11 Ti-6Al-7Nb, 12–14 or commercially pure titanium (CP Ti). 15–19 More recently, a new genera- tion of low modulus beta-titanium alloys have also been produced using SLM. 20–23 Nevertheless, Ti-6Al- 4V with its excellent balance of strength, ductility, and corrosion resistance remains the most popular alloy and has received the most attention. These alloys do not possess any antibacterial properties, however, which is a highly desirable trait for an implant material because the rate of infection after orthopedic implant surgery ranges from 0.5% to 5%. 24–26 Such infections lead to increased recovery time, patient discomfort, and additional strain on medical facilities. 27 Infection rates vary according to the surgery: fracture  5%, primary joint replacement  2%, and total hip and knee reconstructions  14%. 28–30 It has been shown that including copper or silver in an implant as an alloying element could combat surgery-related infections. 31,32 Recently, cast cop- per-containing Ti-6Al-4V has shown > 99% antibacterial ability against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) compared with the base Ti-6Al-4V. 32,33 Silver nanoparticle coatings have also been used to reduce adhesion of bacteria to dental implants and for prevention of biofilm formation. 31 Silver nanoparti- cles are already added to surgical instrumentation, bone replacement materials, and a wide range of prosthetics, with the release of Ag found to reduce bacterial adhesion to surfaces and to prevent the formation of bacterial biofilms. 31 In this article, we report the result of adding elemental addition of Ag or Cu to a prealloyed Ti-6Al-4V powder. EXPERIMENTAL Three different alloys were used in this study: prealloyed Ti-6Al-4V and Ti-6Al-4V containing either 5 wt.% elemental Cu or 0.5 wt.% elemental Ag. The copper content was selected based on the work of Ren et al. 33 who showed that 5 wt.% Cu resulted in a good antibacterial response, while the Ag content was chosen based on the work of Liao et al. 34 who showed that as little as 0.3 wt.% Ag was JOM, Vol. 69, No. 12, 2017 DOI: 10.1007/s11837-017-2589-y Ó 2017 The Minerals, Metals & Materials Society (Published online September 22, 2017) 2719