Surface Modification of Titanium VT6 Alloy Obtained by Additive Technologies Using Reactive Electrospark Treatment

Using additive technologies, in particular electro-beam melting (EBM), it is possible to obtain products of a high degree of complexity, reducing production costs while minimizing the required amount of material. However, products obtained by the EBM method are characterized by surface defects and high surface roughness, which limits their use. Electric spark treatment (EST) makes it possible to eliminate defects and strengthen the surface layers of EBM products during the reactive phase formation, the conditions of which are studied in the work. The structure and phase composition of electric spark layers formed on VT6 samples under different treatment modes with a low-melting near-eutectic Al-9Si electrode are studied. Due to the reactive phase formation during electric spark treatment, a modified layer with a thickness of more than 10 µm containing nanoscale grains of Ti x Al y intermetallics was formed. The surface roughness after EST is several times lower, and the wear resistance is higher by an order of magnitude compared to the original EBM sample made of VT6 alloy. It is shown that EST for 310 seconds using a hypoeutectic Al-9Si electrode, applied energy 47.6 kJ and a pulse frequency of 3200 Hz, reduces the surface roughness by ~9 times due to plasma smoothing of protrusions and filling in cavities during the spreading melt drops on surface.