Journal
MATERIALS & DESIGN
Volume 204, Issue -, Pages -Publisher
ELSEVIER SCI LTD
DOI: 10.1016/j.matdes.2021.109658
Keywords
Additive manufacturing; Laser powder bed fusion; Thermomechanical modeling; Residual stress; Ti-6Al-4V alloy; Material constitutive models; Mechanical threshold stress model; Johnson-Cook plasticity model
Categories
Funding
- Research Strengthening Project of the Faculty of Engineering, King Mongkut's University of Technology Thonburi
- NASA University Leadership Initiative [80NSSC19M0123]
Ask authors/readers for more resources
This study investigated the sensitivity of material constitutive models on thermomechanical responses in laser powder bed fusion additive manufacturing of Ti-6Al-4V. The Johnson-Cook (JC) and Mechanical Threshold Stress (MTS) material plasticity models were compared, with MTS model providing more accurate estimation for cases involving changes in strain rate and temperature. The choice of material models was found to significantly impact the mechanical behavior prediction in LPBF process.
The present study investigated the sensitivity of material constitutive models on thermomechanical responses in laser powder bed fusion additive manufacturing of Ti-6Al-4V. Uniform scan strategies with scan lengths of 0.5,1, and 2 mm were applied so that wide ranges of thermal histories could be generated. The Johnson-Cook (JC) and Mechanical Threshold Stress (MTS) material plasticity models were chosen to capture the influence of strain, strain rate, and temperature. The JC model is a phenomenological model which is known for its easy implementation and excellent agreement with material testing results. On the other hand, the MTS model is a more complex physics-based internal state variable plasticity model that is expected to provide more accurate estimation, particularly for cases involving changes in strain rate and temperature. Numerical results revealed that both JC and MTS models provided a similar stress evolution, however, the plastic strain evolution was more realistic using the MTS model. Moreover, it was found that the maximum strain and the strain rate in the LPBF process are high compared to typical quasi-static testing, i.e., -2% and - 4 s(-1), respectively. Accordingly, the material models should be calibrated with data obtained under similar deformation conditions. The choice of scan length also strongly affects in-plane stress anisotropy. Ultimately, we show both qualitatively and quantitatively the de-pendency of mechanical behavior prediction in LPBF on the choice of material models. (c) 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available