Influence of Compression Process on Amount and Morphology of Porosity in Aluminum Alloy ADC12 Die-casting Products

Porosity in ADC12 aluminum alloy die castings was reduced by compression at room temperature. The shape and the distribution of porosity were three-dimensionally inspected by using X-ray CT. Specimens were subjected to compression two times. To investigate the effects of compression on the shape and the number of pores, X-ray CT was carried out three times in the initial state, after 10%-compression and after 20%-compression, respectively. The X-ray CT confirmed that greater compression reduces the number and volume of pores more effectively, especially for densely distributed porosity. E1lipsoidal porosity was not flattened after uniaxial compression. Moreover, the two-dimensional finite element analyses showed that the distribution of porosity affects the reduction efficiency of compression. These results agreed well with experimental results. By comparing the experimental and numerical resu1ts, itwas concluded that compression effectively reduces the porosity in number and volume, and improves the mechanical properties and air-leakage resistance of pressure vessels made by aluminum alloy die castings.