Strain-induced phase transformation behavior of stabilized zirconia ceramics studied via nanoindentation.

To study the tetragonal-to-monoclinic (T-M) phase transformation behavior under different strain rates and indentation depths, nanoindentation tests were performed on stabilized zirconia ceramics with Continuous Stiffness Measurements. The results indicate decreased phase transformation velocities at both lower and higher strain rates, but increased velocity under medium strain rate during loading. The phase transformation process is sensitive to Ṗ/P but the final volume fractions are almost identical (45%). Furthermore, most of the phase transformation is completed during a short initial time followed by slight linear increase of the M-phase volume fraction with holding time. The phase transformation continuously slowed with increasing indentation depth when indented with a constant strain rate.