Study on the friction and wear properties of 7075-T6 aluminum alloy enhanced by milling and ultrasonic impact treatment

Abstract

This study investigates the effects of milling parameters on the surface friction behavior of 7075-T6 aluminum alloy subjected to ultrasonic impact treatment. A three-dimensional milling and friction-wear model was developed using ABAQUS finite element analysis, examining the influence of milling speed, depth, and feed rate on the coefficient of friction, wear volume, and surface morphology through single-factor experiments. Results indicate that milling parameters affect the friction coefficient in the following order: Vc > f > ap. Specifically, increasing milling speed from 35 m/min to 59 m/min raises the average friction coefficient from 0.305 to 0.387, a 26.88 % increase. At a milling speed of 83 m/min, the friction coefficient and wear volume reach their lowest values of 0.305 and 0.977 mm³, respectively. The wear volume decreases with increasing milling speed and feed rate, while milling depth has a minor effect. The most significant reduction in wear volume, from 5.76 mm³ to 0.977 mm³ (an 83.04 % decrease), occurs as milling speed increases from 35 m/min to 83 m/min. Maximum longitudinal slip during the reciprocating motion primarily occurs at the ends, with both positive and negative peak offsets. Surface damage from 304 stainless steel balls against the 7075-T6 alloy involves adhesive and abrasive wear. At a milling depth of 35 μm, friction-induced compounds in the transfer film mainly consist of Al, C, Fe, Zn, Mg, and Cr.