HIGH-TEMPERATURE PLASTIC-DEFORMATION OF Y2O3-STABILIZED ZRO2 SINGLE-CRYSTALS .3. VARIATION IN WORK-HARDENING BETWEEN 1200-DEGREES-C AND 1500-DEGREES-C

Plastic deformation has been studied in Y2O3-stabilized ZrO2 single crystals oriented for easy {001} <110> slip between 1200 and 1500-degrees-C. The yield stress shows a linear dependence on temperature because defect clusters act as discrete obstacles. These clusters also cause screw dislocations to become jogged, leading to ready production of edge dipoles and very high work-hardening rates (about mu/15). The high hardening on the primary system allows activation of secondary {111} <100> slip, which causes an apparent yield point at the higher temperatures.