Abstract <p>This study presents a computational investigation into the effects of high-temperature dwell time, sintering temperature, and applied pressure on the densification kinetics and grain growth of micrometer-scale boron carbide–based powder mixtures during high-speed pressure-assisted sintering (HSPAS) at pressures ranging from 250 to 1200 MPa. The simulations employed numerical models of electric heating and densification. The densification model relies on the Skorokhod–Olevsky–Stern theory of sintering for porous materials and incorporates grain growth kinetics throughout the sintering process. The results demonstrate that by adjusting the sintering temperature, dwell time, and pressure during HSPAS, one can control the densification behavior and grain evolution. Specifically, appropriate parameter selection shortens the time required for complete densification, significantly suppresses grain growth, and yields a dense microstructure in the sintered sample. At lower-temperature HSPAS conditions, increasing pressure from 250 to 1200 MPa markedly enhances the densification rate and reduces the time for full densification by a factor of 2 to 3. Notably, by optimizing the heating rate and pressure during HSPAS, the densification time can be reduced by two to three times compared to spark plasma sintering under pressures up to 100 MPa, while simultaneously preventing grain growth.</p>