Sustainability Assessment of Additive Manufacturing with Superalloy 718

Claes Fredriksson, Jonas Olsson and Johny Haraldsson

Department of Engineering Science, University West, Trollhättan

Additive manufacturing (AM) is a potentially disruptive technology that is already transforming the production and maintenance of products. For aerospace and high-performance automotive applications, superalloys and powder bed fusion processes are of particular interest. It has been suggested that AM may offer great benefits in terms of sustainability. Light-weighting, with hollow or novel optimized geometries are examples of strategies which will save energy and decrease emissions. There are also opportunities for net-shape forming to use materials more efficiently. Superalloys are, however, very energy intense both in material production and in manufacturing processes, which raises legitimate questions.

This poster shows how materials data and experiments can be used to support an analysis of energy use and carbon footprint in a life-cycle perspective, cradle-to-gate. It covers material extraction, processing, and AM for a Ni-based Superalloy, IN718. The Ashby educational 5-step method for assessment of sustainable development is adapted and applied to assess the metal AM and briefly discuss also economic and social implications of powder-bed fusion technologies. A model in terms of circular economy is also presented.  

Results from a life-cycle inventory (LCI) show that both electron beam melting and selective laser melting required significant specific energy in manufacturing (including powder production), comparable to the embodied energy of the raw material itself. The energy-use is highly dependent on the geometry of the build but AM offers many advantages in all three sustainability dimensions. 
This is partly due to potential material savings and closing material loops, freedom in design, on-demand production as well as possibilities for repair and refurbishment. There are opportunities for high material efficiency in a circular economy context. Due to slow build time and relatively high energy consumption (depending on geometry), AM is not yet feasible for mass production but rather suits small batches of customized or complex components.