ANISOTROPIC MECHANICAL PROPERTIES IN A BIG-SIZED Ti-6Al-4V PLATE FABRICATED BY ELECTRON BEAM MELTING

摘要

In this study, in order to realize the application of the electron beam melting (EBM) technology for the printing of large components, the microstructure and mechanical properties of a big-sized Ti-6Al-4V plate (6 mm× 180 mm×372 mm) additively manufactured by EBM were investigated. The paper focused on the graded microstructure and anisotropic mechanical properties by using x-ray diffraction, optical microscope, scanning electron microscope, microhardness and tensile test. A gradual change in microstructure with an increase in build height was observed. The formation of a graded microstructure was observed and discussed based on the thermal history experienced during printing. The mechanical properties were influenced accordingly by the graded microstructure. Moreover, the specimens which were printed parallel and perpendicular to the printing directions exhibited high elongation of ~18% and ~14%, respectively. The anisotropy in ductility was also observed and discussed according to the columnar prior β.