Effect of Variable-Speed Non-isothermal Cooling Aging on Mechanical and Corrosion Properties of Al-Cu-Mg Alloys
摘要
The effects of employing the variable-speed non-isothermal cooling aging (VNCA) method on the properties and microstructure of Al-Cu-Mg alloys were investigated. This study involved assessments of hardness, tensile strength, friction, wear properties, and electrochemical corrosion resistance. In particular, we scrutinized the VNCA30 + 10 treatment protocol, which involved initial heating to 250 °C, followed by gradual cooling to 150 °C at a rate of 30 °C/h, and subsequent cooling to 100 °C at a rate of 10 °C/h. The results indicate a remarkable hardness improvement of the alloy, measuring up to 155.8 HV. Furthermore, the alloy’s tensile and yield strengths showed increases of 17.6% and 23.9%, respectively. Importantly, the mechanical characteristics of the alloy treated with VNCA surpassed those achieved through constant-speed non-isothermal cooling aging. The electrochemical corrosion icorr and vcorr reached the minimum values of 3.05 × 10−3 mA/cm2 and 0.2102 mm/a. The transmission electron microscopy analysis revealed a significant increase in the number of precipitated phases in the VNCA30 + 10 treated alloy, which were uniformly distributed. The improved distribution significantly bolstered the mechanical properties of the alloy. Moreover, the precipitated phases along the grain boundaries displayed a semi-continuous distribution. Notably, the corrosion resistance of the alloy showed no significant deviation from the performance observed in the constant-speed non-isothermal aging process.