Densification Kinetics and Mass Transport Mechanisms of TiC Ceramics by Pressure‐Assisted Ultrafast Sintering

ABSTRACT

Densification mechanisms in ultrafast sintering remain poorly understood due to the ultrafast heating process and the strongly non‐isothermal conditions. This gap is particularly critical for refractory carbide ceramics, where densification and grain growth kinetics must be precisely tailored to achieve the desired microstructure and mechanical performance. In this work, the densification behavior of titanium carbide (TiC) ceramics during pressure‐assisted ultrafast sintering was quantitatively analyzed using the instantaneous shrinkage data recorded by a spark plasma sintering system. A modified creep model by incorporating temperature‐dependent terms was adopted to describe the densification and grain growth kinetic under non‐isothermal ultrafast sintering, enabling the extraction of the stress exponent and identification of the dominant mass transport mechanisms. At the early stage, the stress exponent decreases with sintering time but remains much larger than 3, corresponding to particle rearrangement‐related process. At the intermediate stage, an excellent linear correlation with n  = 2.8 indicates dislocation glide‐dominated mechanisms, which are also evidenced by TEM observations. At the final stage, lattice diffusion predominantly controls the densification and grain growth process. The mechanical property of the specimen sintered for 75 s exhibits a hardness of 22.1 ± 0.3 GPa and an indentation toughness of 5.1 ± 0.4 MPa·m ^1/2 . This research provides a quantitative framework for understanding mass transport in ultrafast, non‐isothermal sintering, offering guidance for processing refractory ceramics such as TiC.