Study on Inhibition of Self-Aging Behavior of Zn–Ag Alloy by Hyperpressure Solution and Artificial Aging Treatment

Abstract

The hyperpressure solution (HS) is used on Zn-16Ag alloy to break the limit of atmospheric solid solution, and then the precipitation heat treatment is performed for 8 h at 100 °C. The X-ray diffraction pattern of HS Zn-16Ag alloy exhibits no obvious second phase peaks, the dispersive AgZn₃ phases precipitate after precipitation heat treatment. The tensile strength of AS-2 (atmospheric pressure solid solution–precipitation heat treatment–rolling) and HS-2 (HS solid solution–precipitation heat treatment–rolling) Zn-16Ag is 296 and 256 MPa, with elongation of 38% and 59%, respectively. After natural aging, the tensile strength of AS-2 samples decreases by 25.6%, whereas that of HS-2 samples only decreases by 2%. The fine diffusion AgZn₃ precipitated inhibits the growth and dynamic recrystallization of the grains, showing excellent resistance of self-aging. Moreover, HS-2 Zn-16Ag exhibits a more uniform corrosion mode than the AS-2 alloy after immersion tests.