Study of titanium lattice structures fabricated via selective laser melting

• Main Author: Subramaniam, Nellian Alagu
• Other Authors: Yeong Wai Yee
• Format: Final Year Project
• Language: English
• Published: 2016
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/68638
• Institution: Nanyang Technological University

Selective laser melting (SLM) is an additive manufacturing (AM) process that has been gaining widespread recognition partially due to its huge potential in biomedical applications. Titanium alloys are often the preferred choice of material for these applications due to their exceptional properties. However, the use of bulk material to manufacture biomedical implants can cause stress shielding effect due to the mismatch in elastic modulus between the material and bone. Lattice structures are more suitable for implant manufacture as their porous nature helps to minimize the stress shielding effect. In this report, commercially pure titanium (cpTi), Ti-6Aluminum-4Vanadium (Ti64) and titanium-tantalum (Ti-Ta) lattice structures fabricated via SLM are studied. The microstructure, micro-hardness and compression properties of the lattice structures were analysed and compared with those of the bulk material. The porosity and strut dimensions of the fabricated samples were also calculated and the values seemed to deviate from that of the actual CAD model designed. The difference in porosity can be attributed to the layer-by-layer manufacturing technique of SLM and process parameters utilised. On the other hand, the variation in strut dimensions is caused by the presence of partially melted powder particles that were formed during the contour scan of the struts. Next, micro-hardness test was carried out and the results were similar to that of the bulk material. This is expected since the microstructure observed for cpTi, Ti64 and Ti-Ta lattices matched with the microstructure of their respective bulk material. From the compression tests carried out, Ti-Ta lattice structures were identified to be appropriate substitutes for cpTi and Ti64 lattice structures due to their good combination of strength and elastic modulus relative to the two materials.