Microstructure and hardness of FeCrNiCoMn high-entropy alloy coating prepared by laser cladding with pre-alloyed gas atomized powder

High-entropy alloy is a novel material which consists of at least five principal elements with concentration ranging from 5 to 35 at. %. High-entropy alloy has lots of unique features such as excellent mechanical, magnetic and electrochemical properties etc. so that it has potential to serve as surface protective coatings. In this research, a Fe CrNiCoMn high-entropy alloy powder is fabricated using gas atomization process and this powder is deposited on medium carbon steel substrate by laser cladding. The microstructures of the alloy powder and laser-cladding coating are analyzed using scanning electron microscopy (SEM), energy dispersive spectrum (EDS) and X-Ray diffraction (XRD). The hardness of the coating is measured with a microhardness tester. The resistance to high temperature softening of the coating is also investigated under the annealing treatment performed at 300 °C, 500 °C and 700 °C for 4 h respectively. The experimental results show that the alloy powder processed by gas atomization method has better sphericity, and the coating exhibits a microstructure of single face center cubic (FCC) phase, mainly composed of ellipsoidal dendrites and interdendrites. The phase in the microstructure of the coating remains unchanged after the annealing treatments and the morphology has little change below 550 °C annealing treatments but it has obvious change after 700 °C annealing treatment. The hardness of the coating does not change with the annealing treatments.