In-situ Heat Treatment Of FeTiB2 High Modulus Steel By Additional Laser Exposure During L-PBF

Authors:

Nicklas Tönnißen (Max-Planck für Eisenforschung GmbH, Germany),
Shohag Hussain (Leibniz-Institut für Werkstofforientierte Technologien – IWT, Germany),
Hauke Springer (Max-Planck für Eisenforschung GmbH, Germany)

Abstract:

Additive manufacturing of Fe-Ti-B high modulus steels using the laser powder bed fusion (L-PBF) combines innovative processing technology with novel alloy design to enable next generation lightweight design solutions. By the inherent rapid solidification and in-process precipitation an even distribution of nanometer-sized TiB2-particles in a a-matrix is achieved, but porosity and cracks can only be eliminated by a substantial high substrate preheating for FeTiB2 (15 vol.%). Here we demonstrate how the substrate preheating temperature can be substantially reduced by use of intermittent laser exposure between layer depositions for FeTiB2 (12 vol.%). Hence, the molten surface is treated in a second exposure step with a reduced laser power (i.e. 25 – 75 %) as an in-situ heat treatment, aiding in the transformation of brittle metastable compounds to the equilibrium constituent’s ferrite and TiB2. These are not only desirable for improving the stiffness|density ratio, but also exhibit much less susceptibility for cracking.

DOI:

https://doi.org/10.59499/WP225370510