During microfabrication of ceramics by the Colloidal Isopressing method, cracks were a major problem when features with high aspect ratios were molded into the surface. As differential strain recovery (different elastic expansion of the polymer mold material relative to the consolidated powder compact) is one cause of stress that introduces cracking during pressure release, the strain recovery of the consolidated alumina body was investigated. Spheres of different materials with different elastic moduli were embedded within a pre-consolidated slurry and isopressed at 250 MPa. The strain recovery of the powder compact was also measured via a uni-axial compression test. Results showed that cracks did not form when the elastic moduli of the inclusions were greater than 3 GPa. Inclusions were made by consolidating wax (low-modulus) and aluminum (high modulus) powders so that the elastic modulus of the composite was large enough to avoid crack during pressure release. The wax was removed via a low-temperature heat treatment. This heat treatment also strengthened the powder compact so that the residual aluminum powder could be dissolved in a weak acid. Internal cavities could be formed in dense ceramics by this method.