In physics and material science, plasticity, or plastic behavior, is the ability of a solid to undergo irreversible shape changes in response to applied forces.

In the case of some metals, low forces applied to a sample may lead to an elastic behavior: each increase of the load produces a proportional increase of the deformation but, when the load is removed, the sample returns exactly to its original setup. However, once the load exceeds a certain resistance threshold (technically called yield stress), the deformation increases more significantly remaining permanent: this is the plastic behavior of a material.

Plasticity of ceramic mixtures is a very sensitive data that can positively or negatively affect the developing of some production phases. It is in fact a decisive property for the proper production of ceramics support (during pressing or forming). The level of plasticity required can – and must – change according to the product to be produced.