Morphology Transformation of Cellulose Nanofiber in Titanium during Consolidation Process

Cellulose nanofiber (CNF) is regarded as a new-generation reinforcement fiber with its low density and high mechanical properties. However, it has been considered that CNF could lose its outstanding properties due to carbonization. Therefore, CNF has never been consolidated with metal powders. On the other hand, titanium carbide (TiC) fiber is probably obtained by the chemical reaction between the carbonized CNF and titanium (Ti). This study evaluated the morphology transformation of CNF in Ti during consolidation. Moreover, the tensile properties of CNF-added Ti were investigated. CNF was carbonized around 350°C and micrometer-sized and round-shaped TiC crystals were precipitated. In addition, the O atom was distributed into Ti during the CNF carbonization process. Ti–CNF 3.25 wt% compact showed an ultimate tensile strength (UTS) of above 700 MPa and a good fracture elongation. It was demonstrated that the UTS of Ti–CNF 3.25 wt% compact was a higher UTS than the theoretical value estimated from the increment of 0.2% yield stress of Ti by O atoms.