Geometry dependence of microstructure and microhardness for selective electron beam-melted Ti–6Al–4V parts

ABSTRACT

In an additive-manufactured metallic part, distinct and different microstructure and mechanical properties may exist in different areas due to differences in shape and location. Two parts, one with straight-finned structure and the other with curve-finned structure, were fabricated by the selective electron beam melting method using pre-alloyed Ti–6Al–4V ELI powder. Microstructural characterisation of these two parts that have varying fin thickness and shape was carried out to investigate the synthetical influence of 2D planar build geometry and in-fill hatching strategy on selective electron beam melting. It was found that the β interspacing is larger in the curve-finned structure, leading to a lower microhardness as compared to the straight-finned structure. It suggests a slower cooling rate in the curve-finned structure due to the differences in build geometry and in-fill hatching strategy.

KEYWORDS:

• 3D printing
• additive manufacturing
• electron beam melting
• titanium alloy
• microstructure
• microhardness

Acknowledgements

The authors are grateful for financial support provided by A*Star industrial additive manufacturing program: work package 3. We acknowledge the use of resources in Singapore Centre for 3D Printing supported by the National Research Foundation.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCiD

X. P. Tan http://orcid.org/0000-0003-3392-8254

C. K. Chua http://orcid.org/0000-0001-5703-2490