Effects of solution treatment（T4）and solution plus artificial aging treatment（T6）on microstructure and mechanical properties of Al-5Cu alloy have been investigated in direct squeezing casting.It was found that squeezing casting can promote the diffusion rate of atoms during heat treatment and decrease heat treatment time.The mechanical properties of alloys can be improved due to the heat treatment changing the structure.Compared with those of cast alloy

the mechanical properties of alloy treated at 525～530 ℃ for 4 hours can be obviously improved

where the optimized tensile strength of 389.6MPa and elongation of 10.8% can be observed at holding time for 15 hours.Solid solution Al-5Cu alloy in direct squeezing casting exhibits apparently natural ageing characteristics.It is easy to precipitate stable strengthening GP zone and θ’’ phase for Cu atom in the Al-5Cu alloy under the condition of natural environment

which results in the higher mechanical properties of alloys under solid solution plus natural aging condition than those under T6 condition due to the uniformly distributed strengthening phase.