Effects of Powder Oxidation on Impact Toughness of Electron Beam Melt Ti-6Al-4V

Published

August 25, 2017

Author(s)

Edward J. Garboczi, Enrico Lucon, William Grell, Z Loftus, Maciej Kumosa, E Solis-Ramos, Paul Predecki, E Clark

Abstract

Powder quality in additive manufacturing (AM) electron beam melt (EBM) of Ti-6Al-4V components is crucial in determining the critical material properties of the end item. In this study, we report on the effect of powder oxidation on Charpy impact energy of Ti-6Al-4V parts manufactured using EBM. In addition to oxidation, the effects on impact energy owing to hot isostatic pressing (HIP), specimen orientation, and EBM process defects were also investigated. This research has shown that excessive powder oxidation (oxygen content above 0.25 wt % and up to 0.46 wt%) has a dramatic negative influence on impact energy. It was determined that the impact energy of the parts after excessive oxidation was reduced by about seven times. We also report that HIP post-processing has a significant positive effect on the impact toughness, especially for specimens with lower or normal oxygen content. The specimen orientation effect was found to be more prevalent for low oxidation levels. This research has also shown that the reduction in toughness of the oxidized Ti-6Al-4V alloy was most likely caused by the blockage of screw dislocations in α-Ti.

Citation

ACTA Materialia

Pub Type

Journals

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Keywords

Additive Manufacturing, Ti-6Al-4V Powder, EBM, Oxidation, Charpy Impact, Toughness, X-ray computed tomography

Citation

Garboczi, E. , Lucon, E. , Grell, W. , Loftus, Z. , Kumosa, M. , Solis-Ramos, E. , Predecki, P. and Clark, E. (2017), Effects of Powder Oxidation on Impact Toughness of Electron Beam Melt Ti-6Al-4V, ACTA Materialia, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=922430 (Accessed April 20, 2024)