Improved tribological behavior of plasma-nitrided AlCrTiV and AlCrTiVSi high-entropy alloy films

Abstract Plasma nitriding was used to improve the tribological properties of AlCrTiV and AlCrTiVSi high-entropy alloy (HEA) films. The results indicated that after plasma nitriding, the microstructure and tribological property were improved greatly. For plasma-nitrided AlCrTiV, it is still composed of a single BCC solid solution but with a decreased lattice constant, while for plasma-nitrided AlCrTiVSi, a new V4.75Si3N0.58 nitride phase forms in the amorphous matrix, which all lead to the increase of nano-hardness, promoting the reduction of wear degree or wear rate against GCr15 and Al2O3. Due to the perfect balance of hardness and toughness, the plasma-nitrided AlCrTiV HEA film has the lowest friction coefficient (against Al2O3) and the best wear-resistance.