Measurement of Residual Stresses in Titanium Aerospace Components Formed via Additive Manufacturing

Abstract:

In the present study gas tungsten arc welding (GTAW) with automated wire addition was used to additively manufacture (AM) a representative thin-walled aerospace component from Ti-6Al-4V in a layer-wise manner. Residual strains, and hence stresses, were analysed quantitatively using neutron diffraction techniques on the KOWARI strain scanner at the OPAL research facility operated by the Australian Nuclear Science and Technology Organisation (ANSTO). Results showed that residual strains within such an AM sample could be measured with relative ease using the neutron diffraction method. Residual stress levels were found to be greatest in the longitudinal direction and concentrated at the interface between the base plate and deposited wall. Difficulties in measurement of lattice strains in some discrete locations were ascribed to the formation of the formation of localised texturing where α-Ti laths form in aligned colonies within prior β-Ti grain boundaries upon cooling. Observations of microstructure reveal basket-weave morphology typical of welds in Ti-6Al-4V. Microhardness measurements show a drop in hardness in the top region of the deposit, indicating a dependence on thermal cycling from sequential welds.

• Periodical: Materials Science Forum (Volume 777)
• Pages: 124-129
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.777.124
• Online since: February 2014
• Authors: Nicholas Hoye*, Hui Jun Li, Dominic Cuiuri, Anna M. Paradowska
• Keywords: Additive Manufacturing (AM), Fusion Welding, Neutron Diffraction, Residual Stress, Ti6Al4V

References

[1] E. Kraft, Summary of Emerging Titanium Cost Reduction Technologies, (EHK Technologies-for ORNL, Vancouver, WA, 2004), 1-59.

[2] C.A. Brice, B.T. Rosenberger, S.N. Sankaran, K.M. Taminger, B. Woods, R. Nasserrafi, Chemistry control in electron beam deposited titanium alloys`, Materials Science Forum, 618-619 (2009) 155-158.

DOI: 10.4028/www.scientific.net/msf.618-619.155

[3] S. Seong, O. Younossi, B.W. Goldsmith, Titanium: Industrial Base, Price Trends, and Technology Initiatives, RAND Corporation, Santa Monica, California, 2009.

DOI: 10.7249/mg789

[4] B. Baufeld, O.V.d. Biest, R. Gault, Additive manufacturing of Ti–6Al–4V components by shaped metal deposition: Microstructure and mechanical properties, Materials & Design, 31, Supplement 1 (2010) S106-S111.

DOI: 10.1016/j.matdes.2009.11.032

[5] G. Escobar-Palafox, R. Gault, K. Ridgway, Robotic manufacturing by shaped metal deposition: State of the art, Industrial Robot, 38 (2011) 622-628.

DOI: 10.1108/01439911111179138

[6] F. Wang, S. Williams, P. Colegrove, A. Antonysamy, Microstructure and Mechanical Properties of Wire and Arc Additive Manufactured Ti-6Al-4V, Metallurgical and Materials Transactions A, 44 (2013) 968-977.

DOI: 10.1007/s11661-012-1444-6

[7] C. Charles, in: Division for Material Mechanics - Department of Applied Physics, Lulea University of Technology, Lulea, 2008.

[8] J. Ding, P. Colegrove, J. Mehnen, S. Ganguly, P.M. Sequeira Almeida, F. Wang, S. Williams, Thermo-mechanical analysis of Wire and Arc Additive Layer Manufacturing process on large multi-layer parts, Computational Materials Science, 50 (2011) 3315-3322.

DOI: 10.1016/j.commatsci.2011.06.023

[9] P.A. Colegrove, H.E. Coules, J. Fairman, F. Martina, T. Kashoob, H. Mamash, L.D. Cozzolino, Microstructure and residual stress improvement in wire and arc additively manufactured parts through high-pressure rolling, Journal of Materials Processing Technology, 213 (2013) 1782-1791.

DOI: 10.1016/j.jmatprotec.2013.04.012

[10] C. Brice, W. Hofmeister, Determination of Bulk Residual Stresses in Electron Beam Additive-Manufactured Aluminum, Metallurgical and Materials Transactions A, (2013) 1-7.

DOI: 10.1007/s11661-013-1847-z

[11] A.K. Swarnakar, O. Van der Biest, B. Baufeld, Thermal expansion and lattice parameters of shaped metal deposited Ti–6Al–4V, Journal of Alloys and Compounds, 509 (2011) 2723-2728.

DOI: 10.1016/j.jallcom.2010.12.014

[12] J.A. James, J.R. Santisteban, L. Edwards, M.R. Daymond, A virtual laboratory for neutron and synchrotron strain scanning, Physica B: Condensed Matter, 350 (2004) E743-E746.

DOI: 10.1016/j.physb.2004.03.194

[13] S. Ganguly, J.A. James, M.E. Fitzpatrick, A. Tanguy, Automation of a neutron diffractometer for analysis of residual stress inside complex engineering components, Applied Physics A: Materials Science and Processing, 99 (2010) 601-606.

DOI: 10.1007/s00339-010-5615-2

[14] T. Manns, B. Scholtes, DECcalc - A Program for the Calculation of Diffraction Elastic Constants from Single Crystal Coefficients, Materials Science Forum, 681 (2011) 417-419.

DOI: 10.4028/www.scientific.net/msf.681.417

[15] Struers, B. Taylor, E. Weidmann. http://www.struers.com/resources/elements/12/104827/Application_Note_Titanium_English.pdf. cited October 2; 2009.