Compressive properties and micro-structural characteristics of Ti-6Al-4V fabricated by electron beam melting and selective laser melting

Bulk Ti-6Al-4V material and its lattice structures with rhombic dodecahedron unit cells are fabricated by electron beam melting (EBM) and selective laser melting (SLM) method respectively. The effect of part size on the compressive properties and failure modes of the material is taken into consideration. Electronic universal testing machine and Split Hopkinson pressure bar (SHPB) system are adopted for experiments, and the compressive behavior of the additively manufactured materials is investigated accordingly. Meanwhile, multiscale observations are conducted to reveal the macro- and microscopic deformation mechanism. The results showed that the mechanical response of the dense struts as well as micro-lattice structures manufactured by the two processes are quite different. The geometric imperfections are considered to reduce the strength of the undersized struts prepared by EBM. The specimens fabricated by both of the two approaches exhibit elastic-plastic deformation. Besides, the SLM made material is found to be more sensitive to strain rate especially for that below 1000/s than the EBM parts.