Wear and corrosion behaviour of Inconel 718 laser surface alloyed with rhenium

Laser surface alloying (LSA) with rhenium was applied to produce wear and corrosion resistant layers on Inconel 718 alloy. Using a high-power diode laser and 50% overlapping ratio of laser tracks, two kinds of alloyed layers were produced: IN718-14 wt% Re layer with completely dissolved Re powder in substrate, and IN718-28 wt% Re layer with partially dissolved Re powder in substrate. Examinations of microstructure and tribological properties were carried-out of both alloyed layers and substrate under sliding and abrasive wear conditions, as well as electrochemical measurements were made in 3 wt% NaCl solution. It was found that, alloying with 14 wt% Re favourably affects corrosion resistance of IN718, as indicated by significant increase of critical pitting potential (+ 270 mV) at 24% drop of corrosive current, and anodic displacement of corrosion potential (+ 100 mV). In comparison to the IN718 substrate, the layer alloyed with 28 wt% Re has 160% higher hardness, 82% lower sliding wear rate, and 25% higher abrasive wear resistance index.