In situ growth of TiO ₂ microrods via phase transformation in solid‐state sintering for enhanced mechanical properties

Abstract This work proposes a novel strategy for the in situ growth of TiO 2 microrods via solid‐state sintering. The approach fully exploits the accelerated grain growth that occurs during the anatase‐to‐rutile phase transition, in combination with the preferred orientation of rutile TiO 2 along specific crystallographic planes. These factors jointly direct the oriented growth of TiO 2 crystals into rod‐like morphologies, thereby significantly enhancing the mechanical properties of the resulting ceramics. Experimental results demonstrate that optimal growth of microrods is achieved by sintering at the phase transition temperature under vacuum conditions. When this microrod growth strategy is applied during hot‐press sintering, the resulting TiO 2 ceramics exhibit a flexural strength of 276.2 MPa, representing a 78.1% increase compared with samples fabricated without this strategy. This marked improvement in mechanical performance is attributed to the interlocking effect between the microrods and the ordered alignment of the rods induced by uniaxial pressure during hot pressing. This study not only provides a new pathway for strengthening TiO 2 ceramics but also highlights the potential of phase‐transition‐assisted crystal morphology control in the development of structural ceramics.