Additively manufactured aluminium components offer significant potential for industrial applications, particularly for complex geometries and function-integrated structures. However, process-related shape deviations, microstructural inhomogeneities and porosity represent challenges for highly loaded components. For reliable industrial use, mechanical finishing is therefore required to specifically tailor the surface and subsurface properties of additively manufactured aluminium components or individual functional surfaces. In this context, the joint research project addresses these challenges.
As part of the research project funded by the German Research Foundation (DFG), the IFW and the IFMT combine their expertise along the entire process chain, which includes Direct Energy Deposition-Arc (DED-Arc), heat treatment, machining and deep rolling. The objective of this research is to systematically investigate the influence of the individual process steps as well as their interactions on the resulting surface and subsurface properties of additively manufactured aluminium components. Consequently, the required mechanical and technological properties – particularly with regard to increasing fatigue strength – should be reliably tailored. This process-chain-based approach is specifically designed to address industrial requirements, for example in the case of structural components that require certification.
The primary focus of IFMT is the additive manufacturing of aluminium components, utilising the DED-arc process and subsequently subjecting these components to heat treatment. The effects of process parameters on the resulting geometry and microstructure, and the influence of heat treatment strategies on microstructure, are investigated in particular. These factors have been shown to have a significant effect on the resulting material properties and the initial conditions for subsequent process steps. Complementarily, IFW focuses on the mechanical finishing of additively manufactured aluminium components. The turning process generates reproducible surfaces and establishes defined initial conditions for subsequent investigations. Subsequently, the surface is further smoothed by deep rolling, while subsurface hardness and compressive residual stresses are purposefully increased.
Based on the experimental results obtained to date, the influences of the individual process steps and their interactions along the additive–subtractive process chain on the surface and subsurface properties of additively manufactured aluminium components can be reliably described. The investigations show that these properties can be systematically tailored through a coordinated combination of additive manufacturing, heat treatment, machining, and deep rolling. This enables the identification of key levers for establishing suitable initial conditions for fatigue strength assessment.
In the subsequent project phase, the insights gained will be used to derive reliable predictions of the influence of the additive–subtractive process chain on component fatigue life and to validate these predictions experimentally. The results contribute to the targeted optimisation of the mechanical properties of additively manufactured aluminium components and thereby extend the applicability of DED-Arc process for highly loaded aluminium structural components. Moreover, they provide the foundation for the further development of additive–subtractive process chains for industrial applications, as well as for their transfer to practice-oriented component geometries. The project thereby establishes a solid basis for collaboration with industrial partners.
Contact:
For further information, please contact Abdallah Abdelmonaem on+49 511 762 18387 or by email at abdelmonaem@ifw.uni-hannover.de.
