Additively manufactured cellular structures: Impact of microstructure and local strains on the monotonic and cyclic behavior under uniaxial and bending load

In order to meet the demand for optimized light-weight parts, the development of load adapted structures has begun to play a key role in today's research. Promising candidates are complex cellular structures, which can be adapted to the loading conditions by use of Additive Manufacturing techniques. The current study addresses the mechanical behavior of open cellular structures produced by Selective Laser Melting. Samples of Ti–6Al–4V were processed, heat-treated and tested under monotonic and cyclic loading applying both uniaxial and bending loads. To reveal microstructure – mechanical property – relationships an in situ approach using electron back scatter diffraction and digital image correlation was applied. The results clarify the impact of a post-SLM heat treatment on the mechanical performance of cellular structures made from Ti–6Al–4V. Local strains determined by DIC reveal structure weaknesses already at low degrees of deformation and at an early stage of lifetime. The in situ approach helps in understanding the mechanical behavior and allows for local adaptation of the cell design in order to obtain improved load adapted structures.