High integrity repair of aerospace components using laser blown powder directed energy deposition

Abstract

Laser Blown Powder Directed Energy Deposition (LBP-DED) is a form of Additive Manufacturing (AM) that has the potential to transform the way complex and high value metallic aerospace components are repaired. However, the adoption of LBP-DED in aerospace has largely been limited due to the inconsistent and unpredictable nature of microstructural features, including porosity and lack of fusion, which have become synonymous with AM.

LBP-DED is of interest to aeroengine manufacturers for use in the repair of bladed disks (blisks), in particular, for the repair of Ti-6Al-2Sn-4Zr-6Mo (Ti-6246) blisk aerofoils using the dissimilar additive material Ti-6Al-2Sn-4Zr-2Mo (Ti-6242).

In this study, different aspects relevant to the high integrity repair of Ti-6246 components using Ti-6242 deposited via LBP-DED are systematically explored. Aspects investigated include:

• An analysis of the microstructure and microhardness of the Ti-6242 deposit, with particular focus on the interface between the additive material being deposited and the forged substrate. This analysis includes similar (Ti-6242) and dissimilar (Ti-6246) substrate material effects.
• Assessing the influence of the interface being present within a repaired structure, and how different surface preparation methods can have an impact on the quality of the repair, using high cycle fatigue (HCF) testing and X-ray Computer Tomography.
• Exploring the mechanisms behind defect formation when depositing dissimilar materials using in situ high speed x-ray imaging.
• A critical assessment of Ti-6242 powder feedstock material used in the LBP-DED process, and how the properties of the powder feedstock vary dependant on atomisation technique, size range and supplier.
• Establishing a link between the properties of the Ti-6242 powder feedstock, the deposit microstructure, and the HCF performance of the deposited material.

The findings of this study will be used to guide the optimisation of industrial practices to allow the utilisation of LBP-DED in the repair of high integrity aerospace components, such as Ti-6246 blisks.

Metadata

Supervisors:	Todd, Iain
Keywords:	titanium; powder; additive; manufacturing; Ti-6242; Ti-6246
Awarding institution:	University of Sheffield
Academic Units:	The University of Sheffield > Faculty of Engineering (Sheffield) > Materials Science and Engineering (Sheffield)
Academic unit:	School of Chemical, Materials and Biological Engineering
Date Deposited:	28 Oct 2025 15:17
Last Modified:	28 Oct 2025 15:17
Open Archives Initiative ID (OAI ID):	oai:etheses.whiterose.ac.uk:37440

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