Effects of Ce and Ti on the microstructures and mechanical properties of an Al-Cu-Mg-Ag alloy

摘要

The effects of Ce and Ti additions on the microstructures and mechanical properties of an Al-Cu-Mg-Ag alloy have been studied. It has been shown that either Ce or Ti can decrease the as-cast grain size of the Al-Cu-Mg-Ag alloy, in-crease the nucleation ratio for Ω phase as heterogeneous nucleation centers, inhibit the growth of Ω phase during aging, and thus increase the volume fraction and decrease the spacing ofΩ phase. These microstructures increase the yield strength and tensile strength. However, if both Ce and Ti are added to the alloy, they form (Ce,Ti)-contained compounds and increase the grain size during casting, but have no effects on the nucleation and the growth of Ω phase during aging. The alloy contain-ing both Ce and Ti has a relatively lower Vicks hardness and strength compared to the alloy containing either Ce or Ti.