Size effects and shape memory properties in ZrO2 ceramic micro- and nano-pillars

Bulk zirconia ceramics tend to crack when they undergo martensitic transformation, while small-scale samples survive. The relative importance of sample dimension and mean grain size of such ceramics, with reference to the elimination of mismatched transformation strains and therefore cracking, was studied by creating pillars with diameters straddling the mean grain size. The pillars can be transformed through ∼3–8% strain without cracking when their diameter is near or below the bulk grain size, and can be fully recovered.