Preparation, mechanical properties and wear resistance of dual-sized TiC particles reinforced high-entropy alloy cermet coating

Abstract

The replacement of WC-Co cermet coating partially or entirely has evolved as one of the most promising research hotspots in terms of coating properties as well as economic reasons. In this study, the TiC reinforced AlCoCrFeNi high entropy alloy (HEA) composite coating based on new sintering method was explored. Firstly, the combination of spray drying and plasma spheroidization is proposed to fabricate TiC/HEA composite powder for thermal spraying application. After that, the corresponding composite coating was deposited by high velocity air-fuel (HVAF) process. The results show that the developed TiC/HEA powder has a more compact structure and higher sphericity, which helps to improve powder fluidity, meanwhile, with 50 wt% TiC incorporation, the porosity、hardness、bonding strength and fracture toughness of TiC/HEA composite coating are 0.8 % 765.2 HV0.3, 68.1 Mpa and 2.7 MPa m−1/2, respectively, showing simultaneous hardening, densifying and toughening effects after introducing dual-sized TiC particles. Besides, the good wear performances of TiC/HEA composite coating including low wear rate (4.2 × 10−5 mm3 N−1 m−1) and coefficient of friction (0.34) are obtained，indicating a valuable application prospect. In addition, the wear mechanisms of TiC/HEA composite coating are determined by abrasive and oxidation wears and that of grinding ball is abrasive wear and adhesive wears.

Keywords

• High-entropy alloy composite coating
• Dual-sized reinforcement
• Spray drying
• Plasma spheroidization
• Wear resistance