Temperature-dependent R-curve behavior of the lead-free ferroelectric 0.615Ba(Zr0.2Ti0.8)O3–0.385(Ba0.7Ca0.3)TiO3 ceramic

• The maximum fracture toughness of BZT–38.5BCT decreases with increasing temperature.
• We observed an exclusively transgranular fracture for BZT–38.5BCT.
• We correlate the ferroelastic shielding behavior with the ferroelastic properties.

The temperature-dependent crack growth resistance behavior of the lead-free (1 − x)Ba(Zr0.2Ti0.8)O3–x(Ba0.7Ca0.3)TiO3 (x = 0.385) ceramic was characterized using compact-tension specimens from 25 °C to 60 °C. The observed plateau fracture toughness at 25 °C was found to be approximately 37% lower than commercial Pb(Zr,Ti)O3. At elevated temperature, the maximum fracture toughness displayed a decrease, which was found to be related to the temperature-dependent elastic and ferroelastic properties. Mechanical measurements are presented that demonstrate decreasing effective switching strain, coercive stress and Young’s modulus with increasing temperature.