On the Impact of Additive Manufacturing on Microstructural and Mechanical Properties of Stainless Steel and Ni-base Alloys

Recently, additive manufacturing (AM) has gained a lot of interest in industry and academia due to its capability of providing parts of unprecedented geometric complexity. A well-studied and, thus, the most commonly used material for processing via AM is Ti-6Al-4V with applications in the biomedical and aerospace sectors. However, for numerous envisaged applications, different materials, such as stainless steels or Ni-base alloys, have to be contemplated. As these alloys do not undergo a phase transformation upon cooling from solidification to room temperature, the microstructure induced by AM is completely different to that of Ti-6Al-4V. The current paper highlights the impact of different AM techniques, namely selective laser melting (SLM) and electron beam melting (EBM), on the microstructure evolution and concurrent implications for the resulting mechanical properties. Possibilities for direct microstructural design as well as necessities for post-process treatments are presented and discussed.