Ali, H., Ghadbeigi, H. and Mumtaz, K.A. (2018) Residual stress development in selective laser-melted Ti6Al4V: a parametric thermal modelling approach. International Journal of Advanced Manufacturing Technology, 97 (5-8). pp. 2621-2633. ISSN 0268-3768
Abstract
High cooling rates within the Selective Laser Melting (SLM) process can generate large residual stresses within fabricated components. Understanding residual stress development in the process and devising methods for in-situ reduction continues to be a challenge for industrial users of this technology. Computationally efficient FEA models representative of the process dynamics (temperature evolution and associated solidification behaviour) are necessary for understanding the effect of SLM process parameters on the underlying phenomenon of residual stress build-up. The objective of this work is to present a new modelling approach to simulate the temperature distribution during SLM of Ti6Al4V, as well as the resulting melt pool size, solidification process, associated cooling rates and temperature gradients leading to the residual stress build-up. This work details an isotropic enhanced thermal conductivity model with the SLM laser modelled as a penetrating volumetric heat source. An enhanced laser penetration approach is used to account for heat transfer in the melt-pool due to Marangoni convection. Results show that the developed model was capable of predicting the temperature distribution in the laser/powder interaction zone, solidification behaviour, the associated cooling rates, melt-pool width (with 11% error) and melt-pool depth (with 3% error) for SLM Ti6Al4V. The model was capable of predicting the differential solidification behaviour responsible for residual stress build-up in SLM components. The model predicted trends in cooling rates and temperature gradients for varying SLM parameters, correlated with experimentally measured residual stress trends. Thus the model was capable of accurately predicting the trends in residual stress for varying SLM parameters. This is the first work based on the enhanced penetrating volumetric heat source, combined with an isotropic enhanced thermal conductivity approach. The developed model was validated by comparing FEA melt-pool dimensions with experimental melt-pool dimensions. Secondly the model was validated by comparing the temperature evolution along the laser scan path with experimentally measured temperatures from published literature.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © The Author(s) 2018. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. |
Keywords: | Finite Element; Cooling Rate; Temperature Gradient; Selective Laser Melting; Additive Manufacturing; Ti6Al4V; Residual Stress |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Mechanical Engineering (Sheffield) |
Funding Information: | Funder Grant number ENGINEERING AND PHYSICAL SCIENCE RESEARCH COUNCIL (EPSRC) EP/P006566/1 |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 17 May 2018 14:49 |
Last Modified: | 26 Nov 2020 14:48 |
Status: | Published |
Publisher: | Springer Nature |
Refereed: | Yes |
Identification Number: | 10.1007/s00170-018-2104-9 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:130713 |