Abstract

In laser powder bed fusion (LPBF), the effects of operating conditions on thermal gradients and residual stresses are the utmost challenges that require significant attention. The magnitudes of residual stress in the printed layers, as well as the distribution along the printed components, have not been well explained for LPBF parts. In this study, a 3D finite element thermo-mechanical model has been established to investigate the effect of operating conditions on thermal distribution, melt pool evolution, residual stress distribution, and part distortion. The printed AISI 316L stainless steel cubes have been characterized experimentally. The results showed a proportional correlation among the number of layers, thermal distribution, and melt pool dimensions. A combination of compressive and tensile stresses was recorded in the LPBF-ed parts. The Cauchy stresses were maximum in magnitude at the bottom and top surfaces along the xx- and yy-orientations, while these stresses increased in magnitude along with the part-build orientation (zz) within the whole printed cube except the top surface. The Von Mises stresses were minimal than Cauchy stresses. A maximum displacement was identified at the printed components' contours, gradually decreasing from top to side walls and top surface. An inverse correlation was identified among average Von Mises stresses (AVMS), laser power (LP), and hatch distance (HD); however, a proportional relationship is presented between laser scanning speed (LSS) and AVMS. The average displacement (AD) presented an inverse relationship with LSS and HD, while a proportional correlation has been presented between LP and AD. Average thermal distribution (ATD) revealed an inverse effect on AVMS and a proportional effect on AD. In the printed parts, only austenite-gamma phase was identified along (111), (200), and (220) orientations, with a lack-of-fusion defect in the morphology.

Department(s)

Civil, Architectural and Environmental Engineering

Second Department

Mechanical and Aerospace Engineering

Comments

Horizon 2020 Framework Programme, Grant 764935

Keywords and Phrases

AISI 316L stainless steel; FE-modeling and experiments; Laser powder bed fusion; Melt pool evolution; Morphology; Phase formation; Surface roughness; Thermal distribution

International Standard Serial Number (ISSN)

1433-3015; 0268-3768

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2024 Springer, All rights reserved.

Publication Date

01 Jul 2023

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