Machining Mechanism of CoCrFeNiAlX High Entropy Alloys via Ultrasonic Elliptical Vibration Cutting

Abstract This study investigates the micro-cutting mechanism of CoCrFeNiAlX high entropy alloys, focusing on the impact of amplitude, vibration frequency, cutting depth, and the Al element content. The mechanical response of the material is analyzed using simulation methods for both conventional cutting and Ultrasonic Elliptical Vibration Assisted Cutting (UEVAC).The results reveal that under varying vibration parameters and cutting depths, the cutting temperature generated by UEVAC is significantly higher than that in conventional cutting. Reducing the Y-axis amplitude from 90μm to 30μm results in a 50% decrease in cutting temperature. Additionally, cutting temperature is positively correlated with the Al element content, with a molar ratio of 20% leading to a temperature approximately 2.1 times that at a molar ratio of 13%.When keeping cutting parameters constant, UEVAC generates significantly lower cutting forces compared to conventional cutting. Notably, the minimum cutting force is observed with UEVAC using X-axis amplitude of 40μm, Y-axis amplitude of 90μm, and a vibration frequency of 25KHz, representing only about 13% of the conventional cutting force. Furthermore, as the molar ratio of Al element increases in the high entropy alloy, the cutting force initially decreases by approximately 33% when the molar ratio increases from 0 to 13%. However, it then increases by approximately 214% as the molar ratio goes from 13% to 20%.The residual stresses induced by UEVAC on the workpiece surface (within 0-3μm from the machined surface) predominantly manifest as compressive or tensile stresses, significantly smaller than those produced by conventional cutting. The relationship between the residual compressive stress of the workpiece with different Al element contents is as follows: Al1 > Al0.6 > Al0.