Effects of processing parameters such as applied pressure

pouring temperature

die temperature and delaying time on the defects in squeeze-casting Al-Cu alloy were investigated. Experimental results show that there exist two critical applied pressures during squeeze casting. One is the critical pressure PSC

above which shrinkage defects can be eliminated

and the other is the critical pressure PMS

under which macro-segregation can be avoided. The sound castings without shrinkage and macro-segregation defects can be obtained when the applied pressure only is in the range of PSC<P<PMS. With the increase of the applied pressure

the size and numbers of inter-grain eutectic phase and eutectioids are decreased. High pouring temperature can easily result in the formation of gas hole and inclusions in the castings. Meanwhile

it will bring about the macro-segregation and eutectic segregate defects as a result of decreasing PMS. Moderate die temperature and short delaying time before applying pressure are the essential conditions to prepare sound castings without any defects.