Anisotropic constitutive laws for sintering bodies

Material microstructure and properties become anisotropic during the sintering of cofired ceramics, thin films as well as hot pressed powder compounds. The well-known isotropic constitutive laws are no longer able to describe the sintering process in these cases. Experimental evidence of material anisotropy is given in this paper for alumina thin films and hot forged samples. A new transversely isotropic formulation is developed and the constrained sintering of ceramic films and sinter-forging of powder compacts analyzed using this formulation. Finally, comments regarding the expected values of the parameters and experimental techniques to measure them are presented.