A Phase-Field-Micromechanics Study on the Microstructural Evolution during Viscous Sintering

Abstract

In the manufacturing process of high-performance particulate materials, viscous sintering plays a crucial role, particularly in fields such as polymer processing and additive manufacturing. The interactions between microscopic particles, their flow behavior, and the evolution of porosity during the viscous sintering process directly influence the material's density and mechanical properties. Therefore, developing efficient modeling techniques to simulate the viscous sintering process is essential for optimizing sintering technology. However, the large deformations and dynamic surface evolution inherent in the viscous sintering of particulate materials present challenges to traditional methods based on the sharp interface model. To address these challenges, we propose a thermodynamically consistent diffusion interface model, referred to as the phase-field-micromechanics model, to analyze the evolution of various physical quantities throughout the viscous sintering process. This model implicitly describes the evolution of particle morphology through an introduced phase-field variable. Through comparisons with analytical solutions and experimental data, we rigorously validate the correctness of the proposed model qualitatively and quantitatively under both isothermal and non-isothermal conditions. Using the proposed model, we explore the development of strain and stress during the sintering process, as well as the effects of particle size, shape and arrangement on the overall sintering behavior. The evolution of these characteristic indicators allows for a clear observation of the viscous sintering process, which is vital for understanding the mechanisms behind viscous sintering and for guiding industrial production.