TY  - JOUR
A1  - Pauzon, Camille
A1  - Mishurova, Tatiana
A1  - Evsevleev, Sergei
A1  - Dubiez-Le Goff, Sophie
A1  - Murugesan, Saravanakumar
A1  - Bruno, Giovanni
A1  - Hryha, Eduard
T1  - Residual stresses and porosity in Ti-6Al-4V produced by laser powder bed fusion as a function of process atmosphere and component design
JF  - Additive manufacturing
N2  - The influence of the process gas, laser scan speed, and sample thickness on the build-up of residual stresses and porosity in Ti-6Al-4V produced by laser powder bed fusion was studied. Pure argon and helium, as well as a mixture of those (30% helium), were employed to establish process atmospheres with a low residual oxygen content of 100 ppm O-2. The results highlight that the subsurface residual stresses measured by X-ray diffraction were significantly lower in the thin samples (220 MPa) than in the cuboid samples (645 MPa). This difference was attributed to the shorter laser vector length, resulting in heat accumulation and thus in-situ stress relief. The addition of helium to the process gas did not introduce additional subsurface residual stresses in the simple geometries, even for the increased scanning speed. Finally, larger deflection was found in the cantilever built under helium (after removal from the baseplate), than in those produced under argon and an argon-helium mixture. This result demonstrates that complex designs involving large scanned areas could be subjected to higher residual stress when manufactured under helium due to the gas's high thermal conductivity, heat capacity, and thermal diffusivity.
KW  - Residual stresses
KW  - Laser powder bed fusion
KW  - Process atmosphere
KW  - Helium
KW  - Ti-6Al-4V
Y1  - 2021
U6  - https://doi.org/10.1016/j.addma.2021.102340
SN  - 2214-8604
VL  - 47
PB  - Elsevier
CY  - Amsterdam
ER  -