Hot forging characteristics of transformation-toughened Al2O3/ZrO2 composites

Abstract

Fine grain, transformation-toughened Al2O3/ZrO2 (tetragonal, 5–30 vol. %) composites can exhibit both large deformation strains (80%) and strain rates (> 0.001 s−1) without tearing, cavitating, or cracking during hot forging at 1500 °C. Deformability increases with ZrO2 content. The Al2O3 grains grow, develop a crystallographic orientation, and form column structures with increasing deformation. The deformation behavior of the composite series primarily depends on the content of the ZrO2 phase. In this regard, two deformation regimes were observed that appear to be separated by the volume fraction where the ZrO2 phase might form a connective network.