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Laser sintering of PA12 particles studied by in-situ optical, thermal and X-ray characterization
- Source :
- Additive Manufacturing, 52:102624. Elsevier
- Publication Year :
- 2022
- Publisher :
- ELSEVIER, 2022.
-
Abstract
- The microstructure of products manufactured by selective laser sintering (SLS) is known to be highly dependent on various process and material parameters. The latter thus also affect the final part properties. While most work has focused on ex-situ characterization of the printed parts, little is known about the time-dependent microstructure development during sintering. In this work, we present direct observations of the microstructural evolution during laser sintering of polyamide 12 (PA12) particle doublets by in-situ synchrotron wide angle X-ray diffraction (WAXD), using our in-house developed laser sintering setup. Simultaneously, the neck growth between the particles and the temperature are captured via optical and infrared microscopy. We show that isothermal crystallization experiments under quiescent conditions are not sufficient to describe crystallization in a non-isothermal process like SLS. The enhanced crystallization kinetics in small particles suggests that both temperature and flow play a role. This finding was corroborated by the critical Weissenberg numbers estimated from rheological reptation and Rouse time scales. Furthermore, a microstructure survey has been carried out by microtoming thin slices of the sintered doublets. Both optical and atomic force microscopy reveal significant differences in the crystalline structure of the laser-affected zone as compared to the un-sintered region.
- Subjects :
- Technology
Science & Technology
Additive manufacturing
Materials Science
In-situ WAXD
Biomedical Engineering
Materials Science, Multidisciplinary
MECHANICAL-PROPERTIES
SMALL-ANGLE
Industrial and Manufacturing Engineering
Engineering, Manufacturing
Polyamide 12
Engineering
NYLON-12
Selective laser sintering
ENERGY DENSITY
SCATTERING
General Materials Science
POLYMERS
Crystallization
Engineering (miscellaneous)
KINETICS
TRANSITION
FLOW-INDUCED CRYSTALLIZATION
NUCLEATION
Subjects
Details
- Language :
- English
- ISSN :
- 22148604
- Database :
- OpenAIRE
- Journal :
- Additive Manufacturing, 52:102624. Elsevier
- Accession number :
- edsair.doi.dedup.....421f2436b2dd47feabd4122e4b12ab92