Tensile Behavior of a Titanium Alloy Additively Manufactured via Selective Electron Beam Melting

摘要

Additive manufacturing or 3D-printing of titanium alloys with a high strength-to-weight ratio holds significant interest in the aerospace and biomedical industries.The purpose of this investigation was to determine microstructure and tensile deformation behavior of a 3D-printed Ti-6A1-4V alloy via selective electron beam melting(SEBM).Plentiful multi-oriented α-1amellae were present in the prior columnar(3 grains,which were oriented in the building direction because of the presence of temperature gradients during 3D-printing.The processing parameters selected in this study ensured superior strength and high ductility by controlling the thickness of a-1amellae,with both surpassing the values specified in the ASTM standard.The horizontally orientated 3D-printed alloy demonstrated a certain extent of strain rate sensitivity which decreased with increasing strain,suggesting that dislocation slip was a predominant deformation mode,since the fine and abundant multi-oriented a-1amellae could impede the formation of extension twinning.Fracture surface was observed to be characterized by typical dimples and some entrapped gas pores.