Effect of Secondary Aging on Microstructure and Properties of Cast Al-Cu-Mg-Ag Alloy

The Al-Cu-Mg-Ag alloy after secondary aging of T6I4 was investigated by hardness measurement, tensile test, friction and wear test, exfoliation corrosion test, intergranular corrosion test, electrochemical corrosion test. Scanning electron microscopy and transmission electron microscopy were used to observe the alloy microstructure. The test results show that the secondary aging can improve the microstructure of the alloy, the mechanical and corrosion properties of the alloy. After single-stage aging at 185 degrees C for 2 h and interrupted aging at 120 degrees C for 9 h, the Omega phase in the alloy are fine and uniformly distributed, and the theta ' phase disappear to be obviously coarse. The hardness value, tensile strength, friction and wear coefficient, and loss weight of the alloy are 162.2 HV, 485 MPa, 1.780, and 10.8 mg, respectively. The corrosion resistance of the alloy was improved, and the exfoliation corrosion grade, intergranular corrosion depth, self-corrosion current density, and corrosion rate were 162.2 HV, 1.780, EA, 26.2 mu m, 0.0028 mA cm-2, and 0.0915 mm a-1, respectively.