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Title: Microstructure and mechanical properties of a high Nb-TiAl alloy fabricated by electron beam melting
Authors: Chen, B
Kan, W
Jing, C
Peng, H
Lin, J
First Published: 1-Oct-2018
Publisher: Elsevier
Citation: Materials and Design, 2018, 160, pp. 611-623
Abstract: Electron beam melting (EBM) has been applied to fabricate a high Nb-TiAl alloy with a fully dense microstructure and good tensile properties at both room and high temperatures. The effects of preheating and melting parameters on melting, solidification, phase transformation and resulting microstructure formation in as-EBM high Nb-TiAl alloy were investigated by performing a design-of-experiments. Results show that the limited EBM processing window can be broadened to produce different characteristic microstructures ranging from nearly fully lamellar γ/α2 to equiaxed γ grains. Such a broadened processing window has been achieved by using stronger preheating beam current. A numerical simulation was performed to understand temperature evolution at a fixed point of interest where electron beam passed several times with a certain line offset within one build layer. Both the preheating and melting stages were considered in the model. Modelling results show that a higher preheating beam current resulted in a longer hold time within the temperature range between 1300 and 1380 °C (i.e. single α-phase region). This helped to produce fine lamellar microstructure in the high Nb-TiAl alloy. Fundamental principles are thus proposed in terms of controlling microstructure formation and fabricating fully dense high Nb-TiAl alloy in as-EBM condition.
DOI Link: 10.1016/j.matdes.2018.09.044
ISSN: 0264-1275
Version: Publisher Version
Status: Peer-reviewed
Type: Journal Article
Rights: Copyright © the authors, 2018. This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License (, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
Description: Supplementary data to this article can be found online at
Appears in Collections:Published Articles, Dept. of Engineering

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