In this study, we use the coextrusion process to make high volume-fraction, nacre-like brick-and-mortar alumina structures with < 10% nickel between the ceramic bricks. We perform strength and toughness tests on these compliant-phase aluminas at temperatures up to 900 °C, both to explore the evolution of toughening with changes in the mortar plasticity and to evaluate the viability of these materials at elevated temperatures. We find that temperature plays an important role in the mechanical performance of these materials. Specifically, we observe that crack-growth resistance can be improved at higher temperatures due to enhanced ductility in the metallic mortar.