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Characterization of Filigree Additively Manufactured NiTi Structures Using Micro Tomography and Micromechanical Testing for Metamaterial Material Models

Authors :
Thomas Straub
Jonas Fell
Simon Zabler
Tobias Gustmann
Hannes Korn
Sarah C. L. Fischer
Publica
Source :
Materials; Volume 16; Issue 2; Pages: 676
Publication Year :
2023
Publisher :
MDPI AG, 2023.

Abstract

This study focuses on the influence of additive manufacturing process strategies on the specimen geometry, porosity, microstructure and mechanical properties as well as their impacts on the design of metamaterials. Filigree additively manufactured NiTi specimens with diameters between 180 and 350 µm and a nominal composition of Ni50.9Ti49.1 (at %) were processed by laser powder bed fusion in a first step. Secondly, they structures were characterized by optical and electron microscopy as well as micro tomography to investigate the interrelations between the process parameters, specimen diameters and microstructure. Each specimen was finally tested in a micro tensile machine to acquire the mechanical performance. The process strategy had, besides the resulting specimen diameter, an impact on the microstructure (grain size) without negatively influencing its quality (porosity). All specimens revealed a superelastic response while the critical martensitic phase transition stress decreased with the applied vector length. As a conclusion, and since the design of programmable metamaterials relies on the accuracy of FEM simulations, precise and resource-efficient testing of filigree and complex structures remains an important part of creating a new type of metamaterials with locally adjusted material behavior.

Details

ISSN :
19961944
Volume :
16
Database :
OpenAIRE
Journal :
Materials
Accession number :
edsair.doi.dedup.....d04b2c74891163379e9ac9bec88a79af
Full Text :
https://doi.org/10.3390/ma16020676