Hydrogen porosity in directional solidified aluminium-copper alloys: In situ observation

Using a temperature gradient stage and real time micro-focus radiography the formation of porosity was observed in situ during the solidification of aluminium-copper alloys. Pore morphology was characterized both in the final structure and as a function of temperature during solidification, providing a qualitative insight into the relative importance of the competing physical processes. The effect of solidification velocity, thermal gradient and alloy composition on both the growth kinetics and final structure of the porosity was quantified. Statistical analysis was used to compare the trends in these results to both diffusion controlled and shrinkage driven pore growth. (C) 1997 Acta Metallurgica Inc.