Effect of minor Ag on microstructure and mechanical properties of ZL114A aluminum alloy

Abstract

The effects of trace element Ag on the mechanical properties and microstructure of ZL114A aluminum alloy were investigated by the universal electron tensile testing machine, optical microscopy, scanning electron microscopy and spherical aberration correction field emission transmission electron microscopy. The results show that the tensile strength and yield strength of the alloy are enhanced with the increase of Ag content. However, no significant impact on the elongation is observed with the addition of Ag. When the Ag content reaches 0.55%(mass fraction), the peak aging tensile strength, yield strength, and elongation of ZL114A aluminum alloy increase from 351 MPa to 369 MPa, 309 MPa to 328 MPa, and 2.36% to 2.93%, respectively. There is no evidence of properties of α-Al dendrite and eutectic Si changing under the same condition. The increase of the Ag content promotes the amount of nucleation particles in GP zones, leading to the denser density of β". Ag atoms are observed in the β" phase under high-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) mode, indicating that Ag atoms inhibit the diffusion of Mg atoms as well as Si atoms in the β" phase and the size of β" phase is reduced as a result.

Keywords

• zl114a aluminum alloy
• ag
• mechanical property
• microstructure
• β" phase