Effects of different Ti and Mg addition as well as heat treatments on the microstructures and mechanical properties of Al-Cu alloys prepared by LFC process were investigated.The results show that the amount and grain size of the brittle phase are increased with the increase of Ti content from 0.3%to0.9% and 1.2%

respectively

which leads to the slight decrease of transverse rupture strength（TRS）of the alloys while the hardness almost keep constant with a lower value.The TRS and hardness of the alloys are almost double the original values after being heat treated by 535℃×4hsolution+70℃water quenching +175 ℃×4haging treatment.When 1.0% of Mg is added into the aluminum-copper alloy with 0.3% Ti

the TRS of the alloy is increased a little while its hardness is increased significantly.The amount of Mg is further increased to 1.5% and 2.0%

hardness of the alloys is continued to increase while the TRS is decreased slightly.The TRS and hardness of the alloys containing different amounts of Mg are increased obviously after being heat treated by 535 ℃×4hsolution+70 ℃ water quenching+175 ℃×4haging treatment

and the optimized result can be presented with 1.5% Mg addition.It is found that diamond grit coated with Ti or adding some amount of Ti into the aluminum-copper alloy can bring a stronger bonding between the metal bonds and diamond grits.