Physical–Mechanical Characteristics and Microstructure of Ti6Al7Nb Lattice Structures Manufactured by Selective Laser Melting

Abstract

The demand of lattice structures for medical applications is increasing due to their ability to accelerate the osseointegration process, to reduce the implant weight and the stiffness. Selective laser melting (SLM) process offers the possibility to manufacture directly complex lattice applications, but there are a few studies that have focused on biocompatible Ti6Al7Nb alloy. The purpose of this work was to investigate the physical–mechanical properties and the microstructure of three dissimilar lattice structures that were SLM-manufactured by using Ti6Al7Nb powder. In particular, the strut morphology, the fracture characterization, the metallographic structure, and the X-ray phase identification were analyzed. Additionally, the Gibson-Ashby prediction model was adapted for each lattice topology, indicating the theoretical compressive strength and Young modulus. The resulted porosity of these lattice structures was approximately 56%, and the pore size ranged from 0.40 to 0.91 mm. Under quasi-static compression test, three failure modes were recorded. Compared to fully solid specimens, the actual lattice structures reduce the elastic modulus from 104 to 6–28 GPa. The struts surfaces were covered by a large amount of partial melted grains. Some solidification defects were recorded in struts structure. The fractographs revealed a brittle rupture of struts, and their microstructure was mainly α’ martensite with columnar grains. The results demonstrate the suitability of manufacturing lattice structures made of Ti6Al7Nb powder having unique physical–mechanical properties which could meet the medical requirements.

Adhesion between Biocomposites and Different Metallic Structures Additive Manufactured

“…The CoCr powder contain grains between 10 µm to 65 µm (MCP HEK Tooling, Lübeck, Germany) and the chemical composition comply with standard ASTM F75 [33] for surgical implants. Based on previous studies and our knowledge of SLM manufacturing [34,35], some process parameters were preliminarily tested. The laser scanning strategy adopted was X/Y which allows a scanning in X direction of "n" layer and in Y direction of "n + 1" layer (rotating each hatch scan 90 • ).…”

Properties Evaluations of Topology Optimized Functionally Graded Lattice Structures Fabricated by Selective Laser Melting

“…Additive manufacturing technology has been certified that can produce high-performance components by adjusting process parameters and adopting appropriated heat treatment [ 9 ]. In particular, selective laser melting (SLM) refers to processes that fabricate the parts through the addition of material in a layer-by layer technique, which has successfully fabricated complex lattice structures [ 10 , 11 , 12 ] and is considered an effective method to fabricate FGLSs.…”

Synthesis, Surface Nitriding and Characterization of Ti-Nb Modified 316L Stainless Steel Alloy Using Powder Metallurgy

“…To modify the composition of 316L stainless steel, titanium (Ti) and niobium (Nb) have also been added in the developed compositions to make this material more promising for implant manufacturing. Pure titanium is one of the biomaterials that has been used in implant manufacturing due to its inherent properties and exceptional corrosion resistance [28][29][30]. In recent times, niobium has also gained considerable attention due to its enhanced properties and potential use in biomedical applications [31][32][33].…”