Study of hot pressing sintering mechanism of aluminosilicate through molecular dynamics simulation

CQ Liu and XX Wang and AM Li, CERAMICS INTERNATIONAL, 51, 35913-35921 (2025).

DOI: 10.1016/j.ceramint.2025.05.313

The traditional sintering process is characterized by its high energy consumption; however, low-temperature hot pressing (HP) sintering presents a viable alternative. This research utilized molecular dynamics (MD) simulations to explore the mechanisms underlying the reduction of sintering temperature during the HP process. Critical parameters, such as the volume shrinkage rate and gyration radius, were analyzed to assess the influence of pressure on sintering behavior. The findings indicated that an increase in pressure from 100 MPa to 1000 MPa resulted in a substantial decrease in sintering temperature, from 1050 K to 450 K. The rate of temperature reduction initially escalated, peaking within the pressure range of 500-600 MPa, before stabilizing at 450 K when the pressure exceeded 800 MPa. A detailed examination of the microscopic mechanisms revealed that as pressure increases, the contact surfaces between particles become dislocated, leading to deformation in both the particles and the pores. This dislocation and deformation enhance surface roughness, which facilitates atomic diffusion driven by surface energy. The process of atomic diffusion effectively fills voids, creates new sintering necks, and reduces pore size, thereby accelerating densification. In contrast to conventional sintering, which necessitates high temperatures to overcome diffusion resistance, the application of pressure during HP significantly diminishes diffusion resistance and lowers the required sintering temperature. Consequently, HP demonstrates considerable potential for enhancing sintering efficiency and minimizing energy consumption.

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