Microstructure and mechanical property of selective laser melted Ti6Al4V dependence on laser energy density
Abstract
Purpose
This paper aims to investigate the influence of laser energy density on microstructure and mechanical properties of the selective laser melted (SLMed) Ti6Al4V to complement the existing knowledge in additive manufacturing of Ti6Al4V for future application of selective laser melting (SLM) in fabricating Ti6Al4V parts.
Design/methodology/approach
Ti6Al4V alloy is fabricated by SLM by adopting various energy densities. Microstructures and mechanical properties of the Ti6Al4V deposited using different energy densities are characterized.
Findings
Both high relative densities and microhardness can be obtained in the optimized processing window. The decrease of martensite width and spacing can improve the microhardness on both XOY and XOZ sections when the applied EV (defined as the laser energy per unit volume) increases. The width of the columnar grain increases with EV, resulting in a stronger anisotropy in microhardness between XOY and XOZ sections. Residual tensile stresses exist in the SLMed Ti6Al4V and increase with an increasing EV. A tensile strength of 1,268 MPa, a yield strength of 1,030 MPa, and an elongation of 4% can be obtained by using the optimized range of EV.
Originality/value
The microstructure of SLMed Ti6Al4V is quantitatively analysed by measuring the size of columnar grains and the martensites. The anisotropy of microstructures and properties in SLMed Ti6Al4V is characterized and its dependence on laser energy density is established. The residual stress in SLMed Ti6Al4V is characterized and its dependence on laser energy density is established. An optimized processing window to deposit Ti6Al4V alloy by SLM is proposed.
Keywords
Acknowledgements
This work is supported by the National High Technology Research and Development Program of China through Program no. 2013AA031606 and the National Natural Science Foundation of China through Program no. 50905068. The authors would like to thank the Analytical and Testing Center of HUST for XRD and SEM measurements. Special thanks for Mr Wu’s SEM operation.
Citation
Han, J., Yang, J., Yu, H., Yin, J., Gao, M., Wang, Z. and Zeng, X. (2017), "Microstructure and mechanical property of selective laser melted Ti6Al4V dependence on laser energy density", Rapid Prototyping Journal, Vol. 23 No. 2, pp. 217-226. https://doi.org/10.1108/RPJ-12-2015-0193
Publisher
:Emerald Publishing Limited
Copyright © 2017, Emerald Publishing Limited