Cavitation behavior upon deformation of an Al-Cu eutectic alloy was studied by densitometry and quantitative microscopy. Tensile specimens were strained to different strain levels at constant strain rates and temperatures over the range of 10-5 to 10-2 s-1 and 400° to 540 °C, respectively. The cavity volume increased with increasing strain and strain rate but decreased with increasing temperature. The increase in cavity volume occurred through an increase in both the number and size of cavities. The cavities were spherical in most of the cases, which was attributed to the diffusion-controlled cavity growth mechanism and its modification when the cavity size reaches the size of a grain. The number and volume of cavities were used to evaluate the nature of the cavity nucleation rate and the level of pre-existing cavities. © 1989 The Minerals, Metals & Materials Society and ASM International.