Ultra-Rapid Sintering: Multiphysics Simulation, Mechanisms, Control And Stabilization – ULTRARAPIDE

Attaining the project objectives requires a coupled approach between the Multiphysics simulation for the different ultra-rapid sintering approaches and the experimental calibration/verification of the developed model/approaches.
This study is organized in 5 tasks (see below). Task 1 is the establishment of the fully coupled Multiphysics simulation tool which describes the SPS and microwaves ultra-rapid sintering processes. Then, in task 2, the initial model will be used along with experiments to understand the main conditions responsible for the “flash event” onset. Based on this knowledge, the Multiphysics simulation tool will be used in task 3 and 4, for the establishment of suitable regulation and homogeneous thermal conditions for this abrupt process. Finally, task 5 is devoted to the incorporation of the sintering aspect of the simulations and for the understanding of the underlying flash sintering mechanisms. As the physical properties of the powder evolve with the sintering, this task will also assist the other tasks for the understanding and stabilization of the flash conditions.

These preliminary studies succeed in showing the possibility to apply a flash (ultra-rapid) sintering to specimens with a thickness of 10 mm. The Flash SPS approach is inherently more stable and ready for the complex shaping of small parts. For the flash microwaves sintering, scalability solutions towards few centimeters shapes are still required. However, an interesting contactless process has been mastered up to 10 mm.

These preliminary studies succeed in showing the possibility to apply a flash (ultra-rapid) sintering to specimens with a thickness of 10 mm. The project next step is oriented in extending the flash microwave sintering from 10 mm to 30mm a critical dimension allowing the first study of complex shapes. For the flash spark plasma sintering the flash process is slightly more stable and ready to try the sintering of small complex shapes in combination with 3D printing and an interface method that I develop for the SPS complex shaping while still investigate the improvement of the process stability.

The flash SPS study has been published in the Journal of the European Ceramics Society (https://doi.org/10.1016/j.jeurceramsoc.2021.09.021) and the Microwave study will be submitted soon.

Flash (ultra-rapid) sintering is a new sintering approach allowing sintering in mere seconds. This project addresses the main inherent heating instabilities, microstructural inhomogeneity and regulation issues of this abrupt process. Flash sintering will be applied to advance sintering techniques such as spark plasma sintering (SPS) and microwave sintering. The main goal is to combine pulsed electrical current or microwave irradiation and/or high pressure to decrease the flash sintering temperature and attain a better control of this process and the sintered microstructures. The multiphysics simulation/modeling will be investigated, on the one hand, for the understanding of all coupled physical parameters, and on the other hand, for the study of the underlying flash sintering mechanisms.
This project strategy is based on five tasks organized in a certain order to reach the project objectives. The first task consists of the establishment of the multiphysics numerical tool which needs to be adapted to the ultra-rapid sintering conditions. Then, this numerical tool will be employed for the determination of the favorable ultra-rapid sintering experimental conditions, the regulation of this abrupt process, and the homogeneity of the physical fields for the scaling up of this process. The last task is dedicated to the fundamental sintering aspect of ultra-rapid sintering and its modeling. This task will be developed along with the others.
The ambition of this project is the establishment of stable and reproducible experimental conditions for the ultra-rapid sintering of metals to dielectric parts (up to 30 mm); each developed sintering process will come with a comprehensive multiphysics model which encompasses all the main physical phenomena.