Titanium alloy functionally gradient materials fabricated by in-situ laser-arc hybrid additive manufacturing

Functionally graded materials (FGMs) are novel and advanced materials, which have been widely used in various fields. The nitrogen in situ enhanced Ti6Al4V gradient material was manufactured using laser-arc hybrid additive manufacturing by adjusting the nitrogen flow rate. The microstructure and mechanical performance of the deposited layer were studied through an optical microscope, scanning electron microscope (SEM), X-ray diffraction (XRD), Vickers hardness, friction wear, and electronic universal testing machine. The results show that the nitrogen in the protective gas ionizes and reacts with Ti in the molten pool to form the strengthening phase TiN under the thermal action of the arc, and the amount of TiN increases with the increase of nitrogen flow. The continuous change of TiN phase volume fraction leads to the continuous variety of microhardness, wear resistance, and mechanical properties of the FGMs component. Finally, the FGMs component was prepared, which the outer layer of has high wear resistance, and the interior has good comprehensive mechanical properties. This research provides a novel solution for AM of high-performance-low-cost titanium alloy FGMs.