Title

Indentation strain rate sensitivity of laser-powder bed fused and electron beam melted Ti–6Al–4V

Abstract

Indentation hardness (Hin) and strain rate sensitivity (SRS) of additive manufactured Ti–6Al–4V (Ti64) alloys fabricated through both laser powder bed fusion (L-PBF) and electron beam melting (EBM) are investigated. One major difference between these processes is the higher cooling rates associated with the L-PBF. The indentation tests were performed at loading rates of 1, 10, and 50 mN/s. The L-PBF alloy showed a higher hardness value (3.45 GPa at 1 mN/s, 3.57 GPa at 10 mN/s, and 3.66 GPa at 50 mN/s) being correlated with its finer grain structure as compared with the EBM counter material (3.12 GPa at 1 mN/s, 3.37 GPa at 10 mN/s, and 3.55 GPa at 50 mN/s). The indentation SRS was explained based on the print orientation and dislocation density. EBM-Ti64 shows a higher SRS (0.0335 compared with 0.0147 in the L-PBF alloy) due to the rotation of α-prismatic planes along the building direction.

Publication Title

Vacuum

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