Mika León Altmann, Daniel Knoop, Kerstin Hantzsche, Anastasiya Toenjes

Materials Today Communications 46 (2025): 112734

https://doi.org/10.1016/j.mtcomm.2025.112734

Through adaption of the process parameters during additive manufacturing, the microstructure of Ti-6Al-4V parts can be tailored through in-situ heat treatment and post processes. The influence of the energy input, described by the line and the volume energy density as well as the influence of the laser power on microstructural features and the resulting fundamental mechanical properties is shown. Higher energy inputs and laser power leading to higher β-phase contents up to 7.4?vol.-% in as-built state and a very fine bimodal to fully lamellar microstructure combining high strength of 1183 MPa with a high ductility of 11.4?% but a low impact toughness of 118 kJ m^-2. Beyond this, hot-isostatic pressing is applied as a secondary heat treatment step, to close low-density defects and tune the properties even further. By adapting the energy inputs during additive manufacturing, the final volume content of precipitation-hardened β-phase and α-morphology can be controlled by adjusting the initial as-built mircostrucutre and the oversaturation of the phases due to in-situ heat treatment of the laser additive manufacturing process. This leads to an increase of the material strength of 11?% to 1095?MPa in combination with an elongation of 12?% and a high impact toughness of 348 kJ m^-2. This shows the potential of additive manufacturing as a preliminary heat treatment step for hot-isostatic pressing, allowing defect-free locally adjusted microstructures, which could combine high strength, ductility and toughness.

 ? 2025 The Author(s). Published by Elsevier Ltd.