Cavity nucleation and growth in an Al-Si-Ge alloy

Cavity nucleation and growth associated with spherical SiGe precipitaties in Al-Si-Ge alloys was investigated experimentally, and the results were analyzed quantitatively using only the experimentally determined cavity nucleation parameters and finite element calculations. It is found that the initial void size in a recently developed Al-0.55Si-2.02Ge alloy increases with the increasing precipitate size. This leads to an increase in the void growth rate with the increasing precipitate size and explains the experimental observation that the tensile ductility decreases with increasing precipitate size even through the critical strain cavity nucleation increases. (AIAA)