Influence of the thermal history on the phase composition of laser directed energy deposited Ti-8.5 wt% Mo alloy

Ti-8.5Mo (wt%) alloy was prepared by laser directed energy deposition (L-DED) from the mixture of cp-Ti and Ti-15Mo powder in the ratio of 50:50 using constant laser power of 600 W. Microstructure of as-printed material was characterized by microhardness mapping, light and scanning electron microsco...

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Main Authors: T. Krajňák, M. Janeček, J. Kozlík, D. Preisler, J. Stráský, M. Brázda, J. Kout, K. Halmešová, J. Džugan
Format: Article
Language:English
Published: Elsevier 2022-10-01
Series:Materials & Design
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S0264127522006712
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author T. Krajňák
M. Janeček
J. Kozlík
D. Preisler
J. Stráský
M. Brázda
J. Kout
K. Halmešová
J. Džugan
author_facet T. Krajňák
M. Janeček
J. Kozlík
D. Preisler
J. Stráský
M. Brázda
J. Kout
K. Halmešová
J. Džugan
author_sort T. Krajňák
collection DOAJ
description Ti-8.5Mo (wt%) alloy was prepared by laser directed energy deposition (L-DED) from the mixture of cp-Ti and Ti-15Mo powder in the ratio of 50:50 using constant laser power of 600 W. Microstructure of as-printed material was characterized by microhardness mapping, light and scanning electron microscopy employing EDS technique and local X-ray diffraction measurements. In particular, the influence of the baseplate preheating to 500 °C on microstructure evolution was determined. The microstructure of the as-deposited samples consists of columnar grains orientated parallel to the building direction. Volume fraction of α, β and ω phases, and consequently also microhardness, vary for different positions within the sample due to different thermal history during the printing process. Bottom part of the sample contains increased fraction of α phase due to longer exposure to temperatures favorable for α phase precipitation. Preheating of the baseplate provides additional thermodynamic stabilization of the α phase. Numerical model, predicting the temperature evolution in each layer of the sample during deposition and consequently the ultimate phase composition, was developed. The results obtained from the model are consistent with the experimentally observed phase transformations.
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spelling doaj.art-4663bbc372ce4be78c3e9e893d98133d2022-12-22T02:01:12ZengElsevierMaterials & Design0264-12752022-10-01222111049Influence of the thermal history on the phase composition of laser directed energy deposited Ti-8.5 wt% Mo alloyT. Krajňák0M. Janeček1J. Kozlík2D. Preisler3J. Stráský4M. Brázda5J. Kout6K. Halmešová7J. Džugan8Charles University, Faculty of Mathematics and Physics, Ke Karlovu 3, 121 16 Praha 2, Czech Republic; Research Centre, University of Žilina, Univerzitná 1, Žilina 01026, SlovakiaCharles University, Faculty of Mathematics and Physics, Ke Karlovu 3, 121 16 Praha 2, Czech RepublicCharles University, Faculty of Mathematics and Physics, Ke Karlovu 3, 121 16 Praha 2, Czech RepublicCharles University, Faculty of Mathematics and Physics, Ke Karlovu 3, 121 16 Praha 2, Czech Republic; Corresponding author.Charles University, Faculty of Mathematics and Physics, Ke Karlovu 3, 121 16 Praha 2, Czech RepublicComtes FHT, a.s., Průmyslová 996, Dobřany 334 41, Czech RepublicComtes FHT, a.s., Průmyslová 996, Dobřany 334 41, Czech RepublicComtes FHT, a.s., Průmyslová 996, Dobřany 334 41, Czech RepublicComtes FHT, a.s., Průmyslová 996, Dobřany 334 41, Czech RepublicTi-8.5Mo (wt%) alloy was prepared by laser directed energy deposition (L-DED) from the mixture of cp-Ti and Ti-15Mo powder in the ratio of 50:50 using constant laser power of 600 W. Microstructure of as-printed material was characterized by microhardness mapping, light and scanning electron microscopy employing EDS technique and local X-ray diffraction measurements. In particular, the influence of the baseplate preheating to 500 °C on microstructure evolution was determined. The microstructure of the as-deposited samples consists of columnar grains orientated parallel to the building direction. Volume fraction of α, β and ω phases, and consequently also microhardness, vary for different positions within the sample due to different thermal history during the printing process. Bottom part of the sample contains increased fraction of α phase due to longer exposure to temperatures favorable for α phase precipitation. Preheating of the baseplate provides additional thermodynamic stabilization of the α phase. Numerical model, predicting the temperature evolution in each layer of the sample during deposition and consequently the ultimate phase composition, was developed. The results obtained from the model are consistent with the experimentally observed phase transformations.http://www.sciencedirect.com/science/article/pii/S0264127522006712Laser directed energy depositionColumnar grainsPhase transformationsMicrohardnessNumerical model
spellingShingle T. Krajňák
M. Janeček
J. Kozlík
D. Preisler
J. Stráský
M. Brázda
J. Kout
K. Halmešová
J. Džugan
Influence of the thermal history on the phase composition of laser directed energy deposited Ti-8.5 wt% Mo alloy
Materials & Design
Laser directed energy deposition
Columnar grains
Phase transformations
Microhardness
Numerical model
title Influence of the thermal history on the phase composition of laser directed energy deposited Ti-8.5 wt% Mo alloy
title_full Influence of the thermal history on the phase composition of laser directed energy deposited Ti-8.5 wt% Mo alloy
title_fullStr Influence of the thermal history on the phase composition of laser directed energy deposited Ti-8.5 wt% Mo alloy
title_full_unstemmed Influence of the thermal history on the phase composition of laser directed energy deposited Ti-8.5 wt% Mo alloy
title_short Influence of the thermal history on the phase composition of laser directed energy deposited Ti-8.5 wt% Mo alloy
title_sort influence of the thermal history on the phase composition of laser directed energy deposited ti 8 5 wt mo alloy
topic Laser directed energy deposition
Columnar grains
Phase transformations
Microhardness
Numerical model
url http://www.sciencedirect.com/science/article/pii/S0264127522006712
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