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One of the limitations of commercially available metal additive manufacturing (AM) processes is the minimum feature size most processes can achieve. A proposed solution to bridge this gap is microscale selective laser sintering (μ-SLS). The advent of this process creates a need for models which are able to predict the structural properties of sintered parts. While there are currently a number of good SLS models, the majority of these models predict sintering as a melting process which is accurate for microparticles. However, when particles tend to the nanoscale, sintering becomes a diffusion process dominated by grain boundary and surface diffusion between particles. As such, this paper presents an approach to model sintering by tracking the diffusion between nanoparticles on a bed scale. Phase field modeling (PFM) is used in this study to track the evolution of particles undergoing sintering. Changes in relative density are then calculated from the results of the PFM simulations. These results are compared to experimental data obtained from furnace heating done on dried copper nanoparticle inks, and the simulation constants are calibrated to match physical properties.
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This content will become publicly available on July 1, 2026
Sintering Mechanisms in Metal Extrusion-Based Sintering-Assisted Additive Manufacturing: State-of-the-Art and Perspectives
Abstract Extrusion-based sintering-assisted additive manufacturing (ES-AM) enables the fabrication of intricate metal structures, spanning from simple geometries to complex lattice structures. Sintering plays a vital role in metal densification that requires effective design and optimization of sintering processes for high-quality sintered parts. Notably, sintering behaviors in ES-AM differ from those in traditional methods, primarily due to the heterogeneous distribution of particles and pores induced by the anisotropic fabrication nature of additive manufacturing (AM). This review offers an overview of sintering processes and mechanisms fundamental to ES-AM. Theories governing solid-state sintering and liquid-phase sintering are summarized to advance a thorough comprehension of the associated sintering mechanisms. Computational studies on sintering processes at different length scales are also discussed, including atomic-level molecular dynamics, microlevel simulations (Monte Carlo, phase field, and discrete element method), and macroscopic continuum models. The distinctive anisotropic sintering behaviors in the ES-AM process are further elucidated across multiple levels. Ultimately, future directions for ES-AM, encompassing materials, sintering process, and sintering mechanisms, are outlined to guide research endeavors in this field. This review summarizes multiscale sintering behaviors in both traditional manufacturing and AM, contributing to a deeper understanding of sintering mechanisms and paving the way for innovations in the next generation of manufacturing.
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- Award ID(s):
- 2224309
- PAR ID:
- 10645847
- Publisher / Repository:
- ASME
- Date Published:
- Journal Name:
- Journal of Manufacturing Science and Engineering
- Volume:
- 147
- Issue:
- 7
- ISSN:
- 1087-1357
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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