Research on the influence of ultra-low temperature extreme environments on the surface quality and fatigue life of FeCoCrNiAl0.6 high entropy alloy

Abstract

This study examines the impact of low-temperature cooling on the surface integrity and fatigue properties of the FeCoCrNiAl0.6 high entropy alloy during machining. Utilizing Abaqus2023/Fe-safe simulations, liquid nitrogen cooling, and fatigue tensile tests, it was observed that low-temperature machining improves surface quality and increases tensile strength and fatigue life compared to room temperature machining. At a cutting speed of 2800 mm/min while the temperature drops to −120 °C, the surface roughness can be minimized to the maximum extent possible. Yield strength and tensile strength increased by 7.6 % and 12.5 %, respectively, at this condition, compared to room temperature. Moreover, material strength improves significantly under low-temperature conditions, with yield and tensile strengths at −120℃ being 1.16 and 1.4 times higher than at room temperature. The fatigue life of specimens also improved under low-temperature conditions, with lives reaching 2.82 × 106 cycles at −120℃, an 86.9 % increase over room temperature. The study concludes that optimal machining performance is achieved at higher cutting speeds and shallower cutting depths under low-temperature conditions.