TY - JOUR
T1 - Dynamic laser beam shaping by means of a deformable mirror to tailor microstructure in Directed Energy Deposition
AU - Bremer, Scholte J.L.
AU - Luckabauer, Martin
AU - Aarts, Ronald G.K.M.
AU - Römer, Gert-Willem R.B.E.
N1 - Publisher Copyright:
© 2025 The Authors
PY - 2025/3/20
Y1 - 2025/3/20
N2 - In Laser-based Direct Energy Deposition (DED-L), the resultant mechanical properties depend on thermal cycles during deposition. Traditionally these cycles are usually optimized by tuning the laser power, traverse speed of the laser beam or material feed rate. By adapting, in real-time, the spatial power density distribution (intensity profile) in the focal spot of the laser beam, thermal cycles and thus the microstructure can be further tailored during processing. In this paper, a developed dynamic beam shaping setup, based on a deformable mirror, is used to deposit single tracks, where the high power laser intensity distribution is adapted during deposition. Melt pool monitoring showed that this setup allows to significantly change melt pool morphology during deposition. Next, microstructure analysis (EBSD) of the deposited track shows that various microstructures can be achieved, ranging from a track with larger equiaxed grains in the centre and columnar grains at the bottom and sides of the track to equiaxed grains with a strong crystallographic texture throughout the track. This proofs that the dynamic beam shaping setup is a powerful tool to steer the microstructure and therefore the functional properties of the material.
AB - In Laser-based Direct Energy Deposition (DED-L), the resultant mechanical properties depend on thermal cycles during deposition. Traditionally these cycles are usually optimized by tuning the laser power, traverse speed of the laser beam or material feed rate. By adapting, in real-time, the spatial power density distribution (intensity profile) in the focal spot of the laser beam, thermal cycles and thus the microstructure can be further tailored during processing. In this paper, a developed dynamic beam shaping setup, based on a deformable mirror, is used to deposit single tracks, where the high power laser intensity distribution is adapted during deposition. Melt pool monitoring showed that this setup allows to significantly change melt pool morphology during deposition. Next, microstructure analysis (EBSD) of the deposited track shows that various microstructures can be achieved, ranging from a track with larger equiaxed grains in the centre and columnar grains at the bottom and sides of the track to equiaxed grains with a strong crystallographic texture throughout the track. This proofs that the dynamic beam shaping setup is a powerful tool to steer the microstructure and therefore the functional properties of the material.
KW - UT-Hybrid-D
KW - Directed energy deposition
KW - Dynamic beam shaping
KW - EBSD
KW - Melt pool monitoring
KW - Microstructure
KW - Deformable mirror
U2 - 10.1016/j.jmatprotec.2025.118797
DO - 10.1016/j.jmatprotec.2025.118797
M3 - Article
AN - SCOPUS:105000663223
SN - 0924-0136
VL - 339
JO - Journal of materials processing technology
JF - Journal of materials processing technology
M1 - 118797
ER -