Effects of V on mechanical properties and microstructure of Al-5.0Cu-0.4Mn-0.1Ti-0.1RE alloy prepared by gravity casting were investigated by tensile testing

optical microscope（OM）

scanning electron microscopy（SEM）and energy dispersive spectroscopy（EDS）.The results show that the tensile strength

yield strength and elongation of the alloy reach the peak value by adding 0.25% V both at as-cast and heat treatment state

which is attributed to the fine grain strengthening effect of V in the alloy.With 0.35%V addition

mechanical properties of the alloy are decreased sharply

which is attributed to excessive V accumulating in the alloy to generate a massive Al

10

V phase.During tensile process

the Al

10

V phase is broken severely

resulting in the decrease of tensile strength

yield strength and elongation of the alloy.