Mechanical Properties and Microstructure of DMLS Ti6Al4V Alloy Dedicated to Biomedical Applications
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Faculty of Mechanical Engineering, Bialystok University of Technology, ul. Wiejska 45c, 15-351 Białystok, Poland
2
Department of Biomedical Engineering and Measurements, Technical University of Košice, ul. Letná 1/9, 04200 Košice, Slovakia
*
Author to whom correspondence should be addressed.
Materials 2019, 12(1), 176; https://doi.org/10.3390/ma12010176
Received: 17 December 2018
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Revised: 28 December 2018
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Accepted: 2 January 2019
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Published: 7 January 2019
(This article belongs to the Section Biomaterials)
The aim of this work was to investigate the microstructure and mechanical properties of samples produced by direct metal laser sintering (DMLS) with varied laser beam speed before and after heat treatment. Optical analysis of as-built samples revealed microstructure built of martensite needles and columnar grains, growing epitaxially towards the built direction. External and internal pores, un-melted or semi-melted powder particles and inclusions in the examined samples were also observed. The strength and Young’s modulus of the DMLS samples before heat treatment was higher than for cast and forged samples; however, the elongation at break for vertical and horizontal orientation was lower than required for biomedical implants. After heat treatment, the hardness of the samples decreased, which is associated with the disappearance of boundary effect and martensite decomposition to lamellar mixture of α and β, and the anisotropic behaviour of the material also disappears. Ultimate tensile strength (UTS) and yield strength(YS) also decreased, while elongation increased. Tensile properties were sensitive to the build orientation, which indicates that DMLS generates anisotropy of material as a result of layered production and elongated β prior grains. It was noticed that inappropriate selection of parameters did not allow properties corresponding to the standards to be obtained due to the high porosity and defects of the microstructure caused by insufficient energy density.
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Keywords:
selective laser melting; direct metal laser sintering; porous biomaterials; titanium alloys; mechanical properties
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MDPI and ACS Style
Mierzejewska, Ż.A.; Hudák, R.; Sidun, J. Mechanical Properties and Microstructure of DMLS Ti6Al4V Alloy Dedicated to Biomedical Applications. Materials 2019, 12, 176. https://doi.org/10.3390/ma12010176
AMA Style
Mierzejewska ŻA, Hudák R, Sidun J. Mechanical Properties and Microstructure of DMLS Ti6Al4V Alloy Dedicated to Biomedical Applications. Materials. 2019; 12(1):176. https://doi.org/10.3390/ma12010176
Chicago/Turabian StyleMierzejewska, Żaneta A., Radovan Hudák, and Jarosław Sidun. 2019. "Mechanical Properties and Microstructure of DMLS Ti6Al4V Alloy Dedicated to Biomedical Applications" Materials 12, no. 1: 176. https://doi.org/10.3390/ma12010176
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