TiC distribution and properties of TiC-CrMnFeCoNi coating fabricated by laser cladding with ultrasound

Abstract

The effect of ultrasound on the distribution pattern of TiC and properties of 4 wt% TiC reinforced CrMnFeCoNi coatings fabricated by laser cladding is investigated systematically. The increased amplitude of ultrasonic radiation promotes partial or local dissolution of TiC into C and Ti. Limited amount of C and Ti is solidly dissolved into the matrix resulting in the increase of CrMnFeCoNi lattice constant. Additionally, another C and Ti will be reprecipitated as TiC during the cooling process of laser cladding. The 4 wt% TiC reinforced CrMnFeCoNi coating primarily contains small amount of granular TiC without ultrasonic treatment. With the increase of ultrasound amplitude, the TiC content in the coating of CrMnFeCoNi increases gradually. When the ultrasonic amplitude is 5 μm, the TiC particles have a slight tendency to aggregate and some TiC aggregates into blocks due to the increase in TiC content. However, as the ultrasonic amplitude increases to 10–20 μm, the TiC is distributed in a fishbone shape due to the enhanced vibration effect of ultrasound. Meanwhile, the increasing ultrasonic amplitude increases the hardness and changes the wear mechanism gradually from adhesive to abrasive wear, improving the wear resistance of the coatings. Besides, the corrosion resistance of the coatings is decreased with the increasing ultrasonic amplitude. It is mainly because a lot of TiC distributes along the grain boundary leading to intergranular corrosion with ease.