Superplastic Alumina Ceramics with Grain Growth Inhibitors

Superplastic deformation of alumina ceramics was studied at 1400° to 1450°C and at a strain rate of 4 × 10−5 to 5 × 10−4 s−1. MgO and ZrO2 were introduced to suppress dynamic grain growth. The latter was especially effective; grain growth was minimal in 10‐vol%‐ZrO2‐containing material. Both materials were superplastically stretched under biaxial tension to 100% engineering strain with good surface finishing, demonstrating the feasibility of superplastic forming for alumina ceramics.