Effects of ultrasound on the CrMnFeCoNi coatings with different TiC contents fabricated by laser cladding

Abstract

The present study systematically explores the effect of ultrasound on the CrMnFeCoNi + x(TiC) coatings fabricated by laser cladding. The investigations revealed that the microstructure of the CrMnFeCoNi + x(TiC) cladding layers prepared without ultrasonic assistance is mainly columnar dendrites. With the introduction of ultrasound, the columnar dendrites break up and form equiaxed dendrites. The aggregation of TiC is reduced in the 2 wt% TiC cladding layer prepared by ultrasonic assistance relative to that without ultrasonic assistance. On the other hand, increasing the TiC to 4 wt% in the cladding layer resulted in the spreading of TiC in a wider range along the grain boundary upon ultrasonic treatment. Furthermore, the grain size shows no obvious changes and there is no significant textural characteristics in cladding layers prepared with and without ultrasonic assistance. In contrast, the effect of ultrasound on the TiC distribution is minimal in the cladding layer with 10 wt% TiC. Besides, the introduction of ultrasound could effectively reduce the mass wear rate and the friction coefficient of the CrMnFeCoNi cladding layer with different TiC content except that of 10 wt% TiC cladding layer. The large size and small number of TiC particles in ultrasonic-assisted and non-ultrasonic-assisted 10 wt% TiC cladding layers leads to a decrease in the number of forming corrosion galvanic cell and a decrease in the influence on the dislocation density. Therefore, both ultrasonic-assisted and non-ultrasonic-assisted 10 wt% TiC cladding layers exhibite high electrochemical corrosion resistance. The effect of ultrasonic vibration on CrMnFeCoNi cladding layers with different TiC contents can be explained by the influence of TiC on ultrasonic attenuation.