Ti and SmAlO3 co-affected Al2O3 ceramics: Microstructure, electrical and mechanical properties

Abstract

This work aims to investigate the co-reinforcing effects of Ti and Sm 2 O 3 on Al 2 O 3 ceramics for optimizing electrical and mechanical properties and study the role of elongated SmAlO 3 in toughening. For this purpose, 20 vol% Ti dispersed Al 2 O 3 composites were chosen as matrix and rare earth element oxide of Sm 2 O 3 (0–2.0 at%) was used as the reinforcement to fabricate Sm 2 O 3 added Al 2 O 3 /Ti composites and toughening mechanism caused by elongated SmAlO 3 was discussed. Results indicated that elongated SmAlO 3 with rod-like shape due to the reaction between Al 2 O 3 and Sm 2 O 3 was identified by XRD and EDX analysis. When Sm 2 O 3 content was below 2.0 at%, all composites exhibited excellent electrical conductivity of ∼10 −2 Ωcm. Owing to strengthening and toughening effects caused by SmAlO 3 , 1.5 at% Sm 2 O 3 added composites showed the highest flexural strength and fracture toughness with the values of 567 MPa and 5.53 MPa cm 1/2 . Elongated SmAlO 3 phase contributed greatly to toughening by crack bridging and particle pull-out mechanisms which were determined by aspect ratio of SmAlO 3 particles varying with Sm 2 O 3 content. • Al 2 O 3 ceramics were significantly toughened by the combined addition of Sm 2 O 3 and Ti. • Elongated SmAlO 3 contributed greatly to fracture toughness by crack bridging and particle pull-out mechanisms. • The role of SmAlO 3 in toughening is depended on the aspect ratio varying with Sm 2 O 3 content.