Characterising the fatigue performance of additive materials using the small punch test

Abstract

In recent years the use of Additive Manufacturing (AM) has become increasingly widespread with numerous industries now moving towards large scale manufacture of structurally integral components. The nature of AM offers the ability to manufacture more complex and optimised geometries, such as cooling channels and honeycomb structures, which would not be possible or economically viable to manufacture using more traditional fabrication processes. However, the layer by layer build structure of AM components also introduces a complex and component specific microstructure arising from the rapid cooling rates resulting from the build parameters and geometries, which hence influence the mechanical properties. Therefore, the use of conventional mechanical test approaches to assess the performance of these materials can be limited. This paper will extend upon some of the recent research at Swansea University in applying the innovative small punch fatigue (SPF) experiment to characterise the mechanical performance of AM materials and how they compare to traditionally manufactured variants of the same alloys. Results show excellent agreement with the microstructural morphologies of the different materials, with supporting fractography evidencing the contrasting failure modes.