Abstract
The molten metal pressure in a die cavity was measured insitu during casting of an aluminum alloy (JIS ADC 10) in a 90 tonne cold chamber-type diecasting machine. The solidification structures of the as-cast materials were examined by light and scanning electron microscopy techniques. Mechanical properties of ASTM standard diecast specimens were measured by tensile and charpy impact tests. With increase in injection velocity and/or rising in temperature, the solidified microstructure becomes finer, and the measured mechanical properties, especially ductility becomes superior. When the molten metal pressure in the die cavity was below 600kgf/cm2, the tensile strength of the diecastings was reduced. Microstructural examination revealed that extensive shrinkage microporosity and a coarse dendritic structure were present in the diecastings cast under lower pressures. The reduced strength of the observed microfeatures is discussed in terms of the observed microfeatures.
