Surface Improvement of Ti-6Al-4V Alloy by Deposition of AlCrCoFeMnNi High Entropy Alloy Using TIG Process

A high entropy alloy layer from AlCrCoFeMnNi powders was formed on the surface of the Ti-6Al-4V alloy using the tungsten inert gas (TIG) cladding process to improve the surface properties of the alloy. The design of the experiments using the Taguchi method was used to estimate the surface hardness against the TIG process parameters like the welding current, scanning speed, and shielding gas flow rate. Optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were used to characterize the deposited layer. A Vickers hardness tester was used to evaluate the microhardness of the cladding layer. The results showed that the optimum level of the process parameters that produced high surface hardness was at a current of 50 A, a scanning speed of 0.8 mm/s, and an argon flow rate of 12 L/min. The XRD analysis of the cladding layers revealed that all the layers were composed of BCC and FCC. The examinations of OM and SEM showed that the cladding layers tend to have a dendritic structure consisting of FCC + BCC/B2 and weave-like BCC/B2 precipitates with a small amount of Cr/Fe-sigma phase in the interdendritic structure.

Automated summary

In this study, a high entropy alloy layer was formed on the surface of Ti-6Al-4V alloy using the TIG cladding process to improve its surface properties. The optimal process parameters for high surface hardness were found to be a current of 50 A, a scanning speed of 0.8 mm/s, and an argon flow rate of 12 L/min. The cladding layers were composed of BCC and FCC and exhibited a dendritic and weave-like mixed structure.