Fabrication of Ti-6Al-4V Scaffolds by Direct Metal Deposition

Abstract

Direct metal deposition (DMD) is a rapid laser-aided deposition method that can be used to manufacture near-net-shape components from their computer aided design (CAD) files. The method can be used to produce fully dense or porous metallic parts. The Ti-6Al-4V alloy is widely used as an implantable material mainly in the application of orthopedic prostheses because of its high strength, low elastic modulus, excellent corrosion resistance, and good biocompatibility. In the present study, Ti-6Al-4V scaffold has been fabricated by DMD technology for patient specific bone tissue engineering. Good geometry control and surface finish have been achieved. The structure and properties of the scaffolds were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and tension test. The microstructures of laser-deposited Ti-6Al-4V scaffolds are fine Widmansta¨tten in nature. The tensile and yield strengths of the as-deposited Ti-6Al-4V were 1163 ± 22 and 1105 ± 19 MPa, respectively, which are quite higher than the ASTM limits (896 and 827 MPa) for Ti-6Al-4V implants. However, the ductility of the as-deposited sample was very low (~4 pct), which is well below the ASTM limit (10 pct). After an additional heat treatment (sample annealed at 950°C followed by furnace cooling), both strength (UTS1 045 ± 16, and YS~959 ± 12 MPa) and ductility (~10.5 ± 1 pct) become higher than ASTM limits for medical implants.

X-ray computed tomography and additive manufacturing in medicine: a review

“…In this study, Hollister converted XCT data to CAD data in order to design the bounds of a scaffold structure, contrasting various AM techniques for part production. Other similar studies discussing a variety of methods of additive scaffold production from XCT data can be found elsewhere [44,[46][47][48][49]. In the papers by Mazzoli et al [48] and Dinda et al [49], the authors elaborate on AM production methods through microstructural and mechanical characterisation of manufactured scaffolds built from polyamide containing Al particles and Ti6Al4V respectively.…”

“…Other similar studies discussing a variety of methods of additive scaffold production from XCT data can be found elsewhere [44,[46][47][48][49]. In the papers by Mazzoli et al [48] and Dinda et al [49], the authors elaborate on AM production methods through microstructural and mechanical characterisation of manufactured scaffolds built from polyamide containing Al particles and Ti6Al4V respectively. These authors used scanning electron microscope (SEM) imaging, energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and various mechanical testing methods, to compare the designed implants to bone in which they could hypothetically be implanted.…”

Design for additive manufacturing of composite materials and potential alloys: a review

“…The main reason behind this limitation is the special chemical properties of the main elements in steels, but a lot of concern is given for more development. Different AM processes to fabricate multicomponents of metallic alloys are given in Table 3 [23][24][25][26]. SMD has great advantages in shaping those types of alloys as it depends on creating near-net shaped components by utilizing tungsten inert gas welding.…”

Electron backscatter diffraction characterization of fatigue crack growth in laser metal wire deposited Ti-6Al-4V

“…In previous work, the tensile [6,10] and the low cycle fatigue [9] properties have been evaluated with respect to two specimen orientations. This anisotropy could be related to several parameters such as grain boundary alpha [7,8] and prevalence of defects [9]. Moreover, the building process renders large columnar prior beta grains because of a preferential dendritic growth during solidification in the beta phase, thus from a macroscopic perspective the prior beta grains could also be related to the anisotropic properties [10].…”