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Description
Titanium is known for its high strength to density ratio, excellent corrosion resistance, and admirable strength retention up to high temperatures but lacks in wear resistance and ductility. Discontinuously reinforced TiB whiskers have been successively used to reinforce titanium in recent years but with the increase in hardness, strength, and wear resistance that comes from an increase in percentage of TiB comes a decrease in ductility and fracture toughness. Creating a new composite that incorporates all the advantages of these two compounds, Ti and TiB[subscript w], with an increased hardness, strength, and wear resistance could play large part in improving high strength and lightweight components used in the aircraft, defense, automotive, and biomedical industry. The Selective Laser Melting method with its limited number of processing steps shows great prospect for creating this new composite material. In the biomedical sector, there is a strong mismatch between the Young's modulus of bone and titanium. To reduce the Young's modulus of titanium we look to Ti-based foams. TiH_ is known to decrease ductility but on the other hand, it is also known to act as a pore forming agent when processed with titanium underneath the influence of current. If all Ti, TiB_, and TiH_ powders could be combined in such a manner that produces a uniform distribution of pores, due to the addition to TiH_, amongst a Ti-TiB[subscript w] reinforced matrix, the Young's modulus of titanium can be reduced to better match that of bone. To process such a composite a Selective Laser Melting apparatus was designed and manufactured in the present study to be placed underneath a Nd:YAG pulsed laser. Process parameters investigated in this study include scan speed, and average laser power. These parameters were investigated on CP-Ti as well as Ti-5 wt. % TiB_-2 wt. % TiH_ composites. Both single line scans and full patterned 2D scans were produced. Optical and electron microscopy as well as energy dispersive spectroscopy and X-ray diffraction have been to determine macrostructure, microstructure, phase composition, and type.
