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Uniaxial stress behaviour of Y-TZP

Research paper by G. Subhash, S. Nemat-Nasser

Indexed on: 01 Jan '93Published on: 01 Jan '93Published in: Journal of Materials Science



Abstract

Uniaxial stress behaviour of yttria-tetragonal zirconia polycrystal (Y-TZP) was investigated using a novel split Hopkinson pressure bar technique. The Y-TZP specimens were loaded by a single compressive pulse of predetermined shape and duration. The stress-strain response of the material revealed a linear elastic regime followed by an inelastic regime during which tetragonal to monoclinic transformation occurs. After the transformation was complete, the stress-strain behaviour was found to be elastic with a slope similar to that of the untransformed material. This behaviour suggests that the modulus of the transformed monoclinic zirconia is essentially the same as that of the untransformed tetragonal zirconia, and microcracking during transformation does not significantly affect the subsequent uniaxial stress-strain relation in Y-TZP. Ultrasonic measurements before and after the experiments, and microscopic observations on transformed zirconia specimens also support this conclusion, the latter revealing a very small number of nanometre-size cracks where martensitic laths in partially transformed grains interface with grain boundaries.