Wear and corrosion-resistant Al₂FeCrMnTi_x laser cladding coatings - From powder production by high temperature remelting spheroidization to coating built-up by Laser Powder Bed Fusion

Abstract High entropy alloys (HEAs) have unique mechanical and electrochemical properties in various of fields. Laser powder bed fusion (LPBF) is a prominent additive manufacturing process. It uses thermal energy to bind powder materials together to build plastic or metal parts. The technology has a remarkable effect on improving the corrosion resistance and wear resistance of the agitating blade coatings. However, the traditional gas atomization method (GA) often produce alloy powder (containing refractory element, such as Nb, W) with uneven composition, affecting the quality and performance of specimens. That is why innovative or opposite classical production powder methods are in demand for LPBF. It is worth noting the mechanical alloying - high temperature remelting spheroidization dual process (DP) method could overcome the limitation of high temperature alloying of HEA containing refractory elements and realizes solid alloying of insoluble elements. In this paper, high entropy alloy Al 2 FeCrMnTi x (x=0.25,0.5,0.75,1) is designed by means of composition control. The experimental results show that Al 2 FeCrMnTix is a single phase solid solution BCC structure. With the increase of Ti content, the corrosion resistance of Al 2 FeCrMnTi x HEA coatings were enhanced at a certain range in simulated saturated brine solution. When Ti=0.75, the self-corrosion voltage is -0.179V and the self-corrosion current is 5.764×10 −6 mA·cm −2 . All coatings offer better corrosion resistance than 316L stainless steel substrates. Particularly, the Al 2 FeCrMnTi x HEA coating can greatly improve the microhardness and wear resistance of the material surface. The average microhardness value of HEA coating reaches up to the maximum (726 HV 0.2 ) when Ti=1, which is about 3.6 times that of the base matrix (316L). These findings have clear implications for coatings used to protect surfaces. Overall, It is clear that Ti 0.75 represents lower volume wear rates and smoother wear surfaces, demonstrating better corrosion and wear resistance compared to other coatings.