Microstructure and tribological performance of ultra-high speed laser-cladded AlCrCoFeNi2.1-xTiB2 (x = 0, 0.5, 1.0, 1.5 and 2.0 wt%) high-entropy alloy coatings

Abstract

AlCoCrTeNi2.1- xTiB2 (x = 0, 0.5, 1.0, 1.5 and 2.0 wt%) high-entropy alloy (HEA) composite coatings were prepared on 304 stainless steel by ultra-high speed laser cladding. The microstructure, microhardness and tribological performance of HEA composite coatings were studied in detail. The results showed that HEA composite coatings all mainly consisted of BCC and FCC solid solution phase, and the addition of TiB2 didn’t change the phase structure of HEA composite coatings. The addition of TiB2 improves the microhardness of HEA composite coating. When x = 2.0 wt%, the microhardness of HEA composite coating reaches the maximum value (331.3 ± 5.0 HV), which is nearly 1.5 times that of 304 stainless steel. Accordingly, the wear resistance of the AlCoCrTeNi2.1-xTiB2 HEA composite coatings with TiB2 addition were improved, and the wear rate of AlCoCrTeNi2.1- xTiB2 HEA composite coatings showed a decreased tendency with the increase of x. However, the wear mechanism of HEA composite coatings are the same, mainly oxidation wear, adhesive wear and fatigue wear.