| Formation of macrosegregation in squeeze casting of an Al-7wt%Si alloy was investigated with regard to microstructural evolution under various process variables. The effects on the macrosegregation area of the process variables, such as applied pressure, pouring temperature, die temperature, delay time before pressurization, and height/diameter ratio of the casting were investigated. As the applied pressure increased, the macrosegregation area increased while the length of columnar grains decreased. However, as the die and the pouring temperatures increased, both the macrosegregation area and the length of columnar grains increased. The increase in the delay time for pressurization after pouring also resulted in the increase both of the length of columnar grains and the macrosegregation area. It was found that the macrosegregation area decreases with increasing the amount of equiaxed grains in castings. |
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