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The formation of α + β microstructure in as-fabricated selective laser melting of Ti–6Al–4V

Published online by Cambridge University Press:  25 July 2014

Marlo Simonelli ,
Yau Yau Tse  and
C. Tuck
Marlo Simonelli*
Affiliation:
Department of Materials, Loughborough University, Loughborough LE11 3TU, United Kingdom
Yau Yau Tse
Affiliation:
Department of Materials, Loughborough University, Loughborough LE11 3TU, United Kingdom
C. Tuck
Affiliation:
Additive Manufacturing and 3D Printing Research Group, Department of Mechanical, Materials and Manufacturing Engineering, Faculty of Engineering, The University of Nottingham, Nottingham NG7 2RD, United Kingdom
*
a) Address all correspondence to this author. e-mail: M.Simonelli@lboro.ac.uk
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Abstract

Ti–6Al–4V parts made by the additive manufacturing (AM) technique selective laser melting (SLM) generally show poor ductility due to their fine martensitic microstructure. This study was designed to assess whether a more suitable microstructure can be obtained when long laser/material interaction times are used. As-fabricated components with an α + β microstructure were produced and characterized with various microscopy techniques. The microstructural evolution was discussed in relation to the build platform temperature, the cyclic reheating, and the thermal stresses that developed during the process. The hardness of the samples was also evaluated and discussed. The hardness varied in relation to the different microstructure morphologies observed in the samples and different partitioning of the alloying elements. This study indicates a methodology through SLM to obtain Ti–6Al–4V with an as-deposited α + β microstructure which is more desirable than that the typical fully martensitic microstructure typically obtained after SLM.

Keywords

microstructureannealinghardness

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Type
Articles
Information
Journal of Materials Research , Volume 29 , Issue 17: Focus Issue: The Materials Science of Additive Manufacturing , 14 September 2014 , pp. 2028 - 2035
Copyright
Copyright © Materials Research Society 2014 

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