Boriding effect on CrFeMnNbNi high entropy alloy: Microstructure , micro-nano properties, wear behaviour

Abstract

This study is dedicated to determine the effect of boriding treatment on CrFeMnNbNi alloy. Three phases (Laves, FeNi, FeCr) were determined in the HEA microstructure in accordance with thermodynamic calculations. After the boriding process, a 30-35 mu m thick metallic boriding layer was formed on the surface. Thanks to boride layer, the hardness increased approximately 5 times, reaching up to 2800 HV. In nanoindentation tests performed on HEA, hardness and reduced elastic modulus were highest in the Laves phase (10.9-190 GPa) and lowest in the FeNi phase (2.74-128 GPa). These values reached their highest values (24-302 GPa) in the boride layer. In wear tests, it has been shown that boriding directly affects wear losses and reduces them by up to 96 %.