An investigation on the microstructure and tensile properties of direct squeeze cast and gravity die cast 2024 wrought Al alloy

2024 aluminum alloy, conventionally is used for wrought products. If this alloy is subjected to cast process, a large number of shrinkage porosities will be produced within its microstructure due to its long solidification range. Therefore, in order to see the effect of pressure on the microstructure and reduction of shrinkage porosities of this type of alloy, the effect of squeeze pressure on the microstructure and tensile properties of the alloy was investigated in this research. The results showed that, squeeze casting caused the refinement of the microstructure and reduction in the DAS of the cast structure possibly due to increasing the cooling rate. Increasing the squeeze pressure also led to formation of finer microstructure. Furthermore, higher pressures decreased the percentage of porosity and increased the density of the cast alloy. The ultimate tensile strengths of the squeezed cast samples improved when the squeeze pressure increased. (C) 2008 Elsevier Ltd. All rights reserved.