Experimental study on microstructural evolution, mechanical property, and corrosion behaviour of laser additive manufactured (LAM) titanium alloy grade 5

Additive manufacturing technique has become one of the more prominent manufacturing techniques over the years. The applications of this manufacturing technique are boundless as new process parameters of the operation affect the new structure of the components and give extended applications. The study experimentally investigates the effects of Ytterbium Laser System process parameters on the resultant microstructure of Ti-6Al-4V grade 5 alloy and reinforcement powders. The deposition process was conducted employing a 3 kW (CW) Ytterbium Laser System (YLS-2000-TR) machine, co-axial to the reinforcement powder. The laser scanning speed and power were varied between the intervals of 0.8–1.0 m/min and 900–1000 W. All other parameters kept constant were the rate of gas flow, the spot diameter, and the rate of powder flow. The composites (Ti-6Al-4V/Ti-Al-Si-Cu) produced by the DLMD technique were analysed using investigative techniques, namely, optical microscopy (OPM), scanning electron microscopy (SEM) aided with energy dispersive microscopy (EDS), X-ray diffraction analysis (XRD), microhardness testing, and corrosion rate analysis. From the analysis of the physical properties, the findings show that the geometric properties such as heat affected zone (HAZ) and dilution ratio of the composite samples were greatly impacted by the increase of the laser power of the DLMD technique, showing an increase in these attributes brought about by the interaction between the laser and the material. The addition of the copper (Cu) element enabled the movement of the copper (Cu) into the titanium (Ti) lattice structure resulting in the formation of beta titanium (β-Ti) microstructure. Increment 54.94% is associated with sample 5A which has the most enhanced microhardness of 770 HV_1.0. Sample 6A had shown the most corrosion resistance improvement with 0.00062 mm/year equivalent to 31%.