Investigating the microstructure and high-temperature wear resistance of TiAl/WC coating modified via scanning electron beam

Abstract

In this study, TiAl/WC cladding coatings were modified to improve high-temperature wear resistance by scanning electron beam treatment. Results of the microstructure reveal that the modified coatings are composed of an α₂-Ti₃Al matrix, with a high density of TiC reinforced phase and Ti₃AlC₂ MAX phase. At a scanning speed of 6 mm/s, TiAl/WC coating exhibits superior microhardness and high-temperature wear resistance. After the wear test at 800 °C, the minimum wear volume of modified TiAl/WC coating is 0.084 mm³, which is 4.47 times smaller than that of the TC21 substrate. It is mainly attributed to the dense and uniform distribution of hard TiC with a rigid supporting role and Ti₃AlC₂ MAX phases with a self-lubricating effect. Furthermore, due to the effect of frictional heat, the decomposition of Ti₃AlC₂ promoted the formation of a dense Al₂O₃ protective film. The wear mechanism of modified TiAl/WC coatings exhibits a synergistic occurrence of slight adhesive wear, abrasive wear, and oxidative wear. Scanning electron beam technology shows significant potential for extending the service life of the coatings in high-temperature environments.