High-Strain-Rate Superplasticity in Oxide Ceramics

摘要

A guide for enhancing high-strain-rate superplasticity (HSRS) in oxide ceramics are drawn from existing knowledge for superplasticity and relating phenomena. A trial following the guide led to enhanced HSRS at about 10{sup}(-2) s{sup}(-1) and a maximum tensile ductility of 300-600% in monolithic tetragonal ZrO{sub}2 doped or co-doped with Al{sub}2O{sub}3, MgO, Mn{sub}3O{sub}4 and TiO{sub}2. The trial also led to HSRS at 10{sup}(-1)-10{sup}0 s{sup}(-1) and a maximum tensile ductility of 600-2500% in a dual-phase composite consisting of tetragonal ZrO{sub}2 and MgOAl{sub}2O{sub}3-spinel and in a tri-phase composite consisting of tetragonal ZrO{sub}2, MgO·Al{sub}2O{sub}3-spinel and a-alumina. Post-deformation microstructures suggest that certain secondary phases may be effective in suppressing cavitation damage and thereby enhancing HSRS.