How different metal 3D printing processes change the material behavior during high-speed deformation

What is it about?

Metal 3D printing (also called additive manufacturing) is highly useful for creating complex parts. However, the structural strength of 3D printed metals will change if the fabrication process is changed. Additionally, the material strength can change based upon if the loading is applied quickly or very gradually. This paper investigates both these effects, by testing 3D printed 316L steel in both the as-built condition and after a stress-relief anneal, at several different loading rates. The results show that the different 3D printed processes affect how much the baseline properties change as the loading rate increases. The use of a stress-relief anneal increased the sensitivity of the 316L steel to the applied loading rate.

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Photo by Testalize.me on Unsplash

Photo by Testalize.me on Unsplash

Why is it important?

Characterizing the strength of materials under high-rate loading is critical for automotive and aircraft safety. The safety structures in these applications must be accurately designed to withstand loading at high rates, in order to protect the occupants during crashes. The findings in this paper show that the effects of all the additive manufacturing steps (including post-processing heat treatments) must be taken into account when determining the sensitivity of 3D printed metals to different loading rates. This knowledge will enable more accurate designs of vehicles and aircraft with enhanced crashworthiness.