Heat transfer and phase formation through EBM additive manufacturing of Ti-6Al-4V made cylindrical part

Additive manufacturing is a group of novel intensively studied production processes, through which a 3D object having a desired geometrical shape is produced by layer-upon-layer addition and following joining into monolithic bulk by means of electron beam (EBM) or laser beam (LB) melting. This production route may use both metallic and non-metallic (ceramics and polymers) materials. Since metals and alloys are used, melting/crystallization/sintering involving phase transitions under various heat transfer conditions determine the microstructure and properties of the produced part. The thermal history generated by additive manufacturing is essential in determining the resulting microstructure, material properties, residual stress, and distortion. Study of these processes is of the scientific and technological interest important especially for production of high-performance metallic parts with complicated geometry.

The presented study concentrated on production of simple-shaped (cylindrical) samples made of Ti-6Al-4V alloy. Effect of various heat transfer conditions on the formed microstructure and properties has been investigated. Heat transfer modelling and simulation was done utilizing the Simulia software package. The microstructure of the obtained material has been characterized by means of SEM, HRSEM and XRD. Mechanical properties - tensile test and fatigue –were also determined and correlated with the simulation results.