posted on 2023-02-24, 12:58authored byMing Chen, Steven Van Petegem, Zhiyi Zou, Marco Simonelli, Yau TseYau Tse, Cynthia Sin Ting Chang, Malgorzata Grazyna Makowska, Dario Ferreira Sanchez, Helena Moens-Van Swygenhoven
When Ti-6Al-4V is processed by laser powder bed fusion (L-PBF), acicular martensitic α’-Ti grains are formed within the columnar prior β-Ti grains, resulting in inferior mechanical properties. The application of blended powders in L-PBF enables to tailor the microstructures and obtain a mixture of α’ + β phases. In this work, we demonstrate an effective method to engineer the phase fraction of an L-PBF manufactured Ti alloy using blended powders consisting of Ti-6Al-4V and 3 wt% Fe particles. By varying laser parameters, the as-built microstructures transit from α’ dominated microstructure to a nearly complete β-dominant microstructure. High-speed operando X-ray diffraction during L-PBF processing combined with X-ray fluorescence and EBSD characterization allows for relating microstructure to the spatial distribution of the β-stabilizer Fe under the high cooling rates typical for L-PBF. The as-built microstructure containing large amounts of β phase achieves high strength and enhanced ductility without post-processing heat treatments.
Funding
Underpinning Multi-User Equipment
Engineering and Physical Sciences Research Council
This is an Open Access Article. It is published by Elsevier under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence (CC BY-NC-ND). Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/