Research on low temperature and high strain rate superplasticity of ZrO₂/Ni nanocomposite produced by electrodeposition

Superplasticity of ZrO₂/Ni nanocomposite with a mean grain size of 45 nm produced by pulse electrodeposition was investigated under the tensile test and bulging test. The elongation values obtained by tensile test at temperatures ranging from 420°C to 500°C and strain rates ranging from 8.33 × 10^-4s^-1to 1.67 × 10^-2s^-1are larger than 200%. A maximum elongation of 605% was obtained at a temperature of 450°C and a strain rate of 1.67 × 10^-3 s^-1. SEM was used to observe the microstructures of the samples before and after tensile test. The results indicate that grain growth occurs obviously by the effect of temperature. Superplastic bulging tests were subsequently performed using dies with diameters of 5 mm. The values of H/d exceed 0.5 at temperatures ranging from 420°C to 500°C, indicating the good superplasticity of ZrO₂/Ni nanocomposite.