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7075 aluminum alloy is widely used in the aerospace field, and its use process is subjected to serious corrosion environment. This study aims to explore the influence mechanism of high-speed machining and shot peening water jet composite surface reinforcement on the corrosion behavior of 7075-T6 aluminum alloy. The 7075-T6 aluminum alloy was subjected to shot peening water jet (WJP) and high-speed machining combined with shot peening water jet (HSC-WJP) composite surface reinforcement treatments. The results showed that at a jet pressure of 20 MPa, a jet target distance of 7.5 mm, a nozzle moving speed of 660 mm/min, and a track spacing of 0.33 mm, the self-corrosion potential and polarization resistance were the highest, and the self-corrosion current density was the lowest, with the largest capacitance arc radius. Compared to the WJP treatment, the HSC-WJP-20MPa shifted the self-corrosion potential towards the positive direction by 0.01 V, increased the polarization resistance by 724 Ω cm2, and reduced the self-corrosion current by 7.9 %. The HSC-WJP-7.5 mm reduced the self-corrosion current density by 50.02 % and increased the polarization resistance by 24.9 %. The HSC-WJP-660 mm/min decreased the self-corrosion current density by 52.1 % and increased the polarization resistance by 44.5 %.The samples subjected to HSC-WJP composite reinforcement had fewer and smaller corrosion product sizes. • This study aims to explore the influence mechanism of high-speed machining and shot peening water jet composite surface reinforcement. • The 7075-T6 aluminum alloy was subjected to shot peening water jet (WJP) and high-speed machining combined with shot peening water jet. • The effects of composite reinforcement on the corrosion resistance of 7075-T6 aluminum alloy were investigated. [ABSTRACT FROM AUTHOR]

This work investigates the influences of water jet parameters, including jet pressure, nozzle moving speed, target range, and track interval, on the shot peening of 7075-T6 aluminum alloy. SiC pellets 0.1 mm in diameter are added into the water jet peening (WJP) process. The shot peened workpiece surface is then measured with a roughness tester, a microhardness METER, a METALLURGRAPHIC microscope (MO), and a scanning electron microscope (SEM). The influences of solid pellet WJP on workpiece surface roughness, microhardness, surface residual stress, and surface topography are examined. The results show that jet pressure is positively proportional to surface roughness and microhardness. However as nozzle moving speed and target range increase, the surface roughness and microhardness of the shot peened workpiece begin to decrease. At the track interval of 0.15 mm, the surface roughness of the treated workpiece is a minimum of 0.61 μm. The surface residual stress of the treated workpiece is also notably improved. The residual stress perpendicular to the trajectory is marginally higher than that along the trajectory, but the difference is limited. Further studies reveal that solid pellet WJF treatment of 7075-T6 is the most effective in the jet pressure interval of 25 MPã30 MPa. The optimal nozzle moving speed is 650 mm/miñ750 mm/min. The target range can be selected between 10 and 12.5 mm. The track interval must be greater than 0.1 mm. • This work investigates the influences of water jet parameters, including jet pressure, nozzle moving speed, target range, and track interval, on the shot peening of 7075-T6 aluminum alloy. • The influences of solid pellet WJP on workpiece surface roughness, microhardness, surface residual stress, and surface topography are examined. • Water jet parameter optimization is performed. [ABSTRACT FROM AUTHOR]