To read this content please select one of the options below:

Influence of thermal properties on residual stresses in SLM of aerospace alloys

Mostafa Yakout (Department of Mechanical Engineering, McMaster University, Hamilton, Canada)
M.A. Elbestawi (Department of Mechanical Engineering, McMaster University, Hamilton, Canada)
S.C. Veldhuis (Department of Mechanical Engineering, McMaster University, Hamilton, Canada)
S. Nangle-Smith (Department of Mechanical Engineering, McMaster University, Hamilton, Canada)

Rapid Prototyping Journal

ISSN: 1355-2546

Article publication date: 6 September 2019

Issue publication date: 8 January 2020

1180

Abstract

Purpose

Residual stresses are induced during selective laser melting (SLM) because of rapid melting, solidification and build plate removal. This paper aims to examine the thermal cycle, residual stresses and part distortions for selected aerospace materials (i.e. Ti-6Al-4V, stainless steel 316L and Invar 36) using a thermo-mechanical finite element model. The numerical results are validated and compared to experimental data.

Design/methodology/approach

The model predicts the residual stress and part distortion after build plate removal. The residual stress field is validated using X-ray diffraction method and the part distortion is validated using dimensional measurements.

Findings

The trends found in the numerical results agree with those found experimentally. Invar 36 had the lowest tensile residual stresses because of its lowest coefficient of thermal expansion. The residual stresses of stainless steel 316L were lower than those of Ti-6Al-4V because of its high thermal diffusivity.

Research limitations/implications

The model predicts residual stresses at the optimal SLM process parameters. However, using any other process conditions could cause void formation and/or alloying element vaporization, which would require the inclusion of melt pool physics in the model.

Originality/value

The paper explains the influence of the coefficient of thermal expansion and thermal diffusivity on the induced thermal stresses using experimental and numerical results. The methodology can be used to predict the part distortions and residual stresses in complex designs of any of the three materials under optimal SLM process parameters.

Keywords

Acknowledgements

This work was supported by the Natural Sciences and Engineering Research Council of Canada (NSERC), Grant: RGPIN-2016-06268. The authors also thank Mr Roman Duplak of SimuTech Group Inc. for supporting this project.

Citation

Yakout, M., Elbestawi, M.A., Veldhuis, S.C. and Nangle-Smith, S. (2020), "Influence of thermal properties on residual stresses in SLM of aerospace alloys", Rapid Prototyping Journal, Vol. 26 No. 1, pp. 213-222. https://doi.org/10.1108/RPJ-03-2019-0065

Publisher

:

Emerald Publishing Limited

Copyright © 2019, Emerald Publishing Limited

Related articles