Spatial and geometrical-based characterization of microstructure and microhardness for an electron beam melted Ti–6Al–4V component

Abstract

Electron beam melting (EBM), as one of the layer-by-layer additive manufacturing technologies, is very suitable for producing near net shape metallic parts with complex geometries. This paper presents a spatial and geometrical-based characterization study on an EBM-built Ti–6Al–4V impeller with a base diameter of 100mm and a height of 53mm. The thinnest section of the impeller is ~0.7mm. The porosity, microstructure and mechanical properties were investigated by means of X-ray computed tomography, X-ray diffraction, optical microscopy, scanning electron microscopy and microhardness testing. The findings revealed that only ~0.12vol.% pores with an average diameter of ~12μm were detected in the impeller. This implies that very highly dense parts could be produced by the EBM technology. Moreover, gradual changes in microstructure and microhardness at different locations in the impeller were observed, which is attributed to the complex thermal gradient. On the whole, the impeller exhibited high microhardness values, implying high mechanical properties. These results reveal that EBM is a potential method for fabricating complex-shaped industrial components with superior mechanical performance for practical applications.