The effect of high strain rate impact in Yttria stabilized zirconia

• Published in: Materials & design Vol. 229; p. 111908
• Main Authors: Sanchez, Irati, Axinte, Dragos, Liao, Zhirong, Gavalda-Diaz, Oriol, Smith, Rob
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2023; Elsevier
• Subjects: Lattice defects; Phase transformation; Raman spectroscopy; Strain rate sensitivity; Yttria Stabilized Zirconia; Phase transformation; Strain rate sensitivity; Lattice defects; Yttria Stabilized Zirconia; Raman spectroscopy
• ISSN: 0264-1275; 1873-4197
• DOI: 10.1016/j.matdes.2023.111908

[Display omitted] •When impacting 8YSZ at a small scale a martensitic transformation is triggered at high-strain rates but not at low.•This martensitic transformation, proven by a Raman Spectroscopy, happens at a very surface (∼600 nm) and at a localized manner.•TEM analysis in high-strain rate impact areas confirm the presence of needle shape discontinuities that could become crack induction points.•The result comparison between high and low strain rate impacts suggest a threshold rate inducing a martensitic transformation in 8YSZ. Yttria stabilized zirconia (6-8YSZ) is widely used as a top coat in Thermal Barrier Coatings (TBCs) to protect metallic substrates. These coatings are exposed to severe high strain rate fields along their life, for example during the impact of debris happening in service or during coating removal in repair processes. In this work a water jet and a high strain rate nanoindenter are used to understand the effect of the strain rate (from 10-3 to 108 s−1) on the behaviour of 8YSZ at a small scale. It is observed how, at extremely high strain rates (106–108 s−1), the material suffers from a brittle-dominated failure which induces localized phase transformation. At lower strain rates (10-3−1 s−1), plasticity dominates, and phase transformation is not observed.