TY - JOUR
T1 - Microstructure-topology relationship effects on the quasi-static and dynamic behavior of additively manufactured lattice structures
AU - Hazeli, Kavan
AU - Babamiri, Behzad Bahrami
AU - Indeck, Joseph
AU - Minor, Andrew
AU - Askari, Hesam
N1 - Funding Information:
This work was completed under the NASA Marshall Space Flight Center (MSFC) Grant and Cooperative Agreement (contract number: 80MSFC18M0012). The author would like to thank Dr. Omar Mireles at MSFC for his assistance in manufacturing the lattice structure and his valuable inputs and discussion during the project. The author would also like to thank Dr. Hrishikesh Bale at Carl Zeiss X-ray Microscopy located Pleasanton, CA for the X-ray micro-computed tomography imaging.
Publisher Copyright:
© 2019
PY - 2019/8/15
Y1 - 2019/8/15
N2 - This study demonstrates a relationship between manufacturing variables including design topology and post-processing heat treatment on the porosity distribution, quasi-static, and dynamic behavior of additively manufactured lattice structures (AMLS). Lattice structures were manufactured out of Inconel 718 using selective laser melting technique with four different topologies. The effect of heat treatment on the porosity size and distribution was examined using X-ray computed tomography for as-built (AB), stress relieved (SR), and hot isostatic pressed (HIP) plus solution aged (SA) heat-treatment conditions. It was noticed that reduction of porosity in the as-built samples, as a result of SR, was greater compared the porosity reduction due to the subsequent HIP plus SA. Quasi-static and dynamic loading was conducted and it was found that the deformation trends of each topology were independent of the strain rate. It was also found that the stress relieving heat treatment process enhances the quasi-static and dynamic flow stress after yielding. However, further heat-treating, including HIP and SA, for the same topology were not as effective as the initial SR process. Furthermore, the validity of digital image correlation in measuring average global strain and the validity of using a Kolsky bar for measuring dynamic mechanical behavior of AMLS are discussed.
AB - This study demonstrates a relationship between manufacturing variables including design topology and post-processing heat treatment on the porosity distribution, quasi-static, and dynamic behavior of additively manufactured lattice structures (AMLS). Lattice structures were manufactured out of Inconel 718 using selective laser melting technique with four different topologies. The effect of heat treatment on the porosity size and distribution was examined using X-ray computed tomography for as-built (AB), stress relieved (SR), and hot isostatic pressed (HIP) plus solution aged (SA) heat-treatment conditions. It was noticed that reduction of porosity in the as-built samples, as a result of SR, was greater compared the porosity reduction due to the subsequent HIP plus SA. Quasi-static and dynamic loading was conducted and it was found that the deformation trends of each topology were independent of the strain rate. It was also found that the stress relieving heat treatment process enhances the quasi-static and dynamic flow stress after yielding. However, further heat-treating, including HIP and SA, for the same topology were not as effective as the initial SR process. Furthermore, the validity of digital image correlation in measuring average global strain and the validity of using a Kolsky bar for measuring dynamic mechanical behavior of AMLS are discussed.
KW - Additive manufacturing
KW - Lattice structure
KW - Porosity
KW - Strain rate effect
KW - X-ray computed tomography
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U2 - 10.1016/j.matdes.2019.107826
DO - 10.1016/j.matdes.2019.107826
M3 - Article
AN - SCOPUS:85065714624
SN - 0264-1275
VL - 176
JO - Materials and Design
JF - Materials and Design
M1 - 107826
ER -