Microstructure and mechanical properties of Al2O3 particle reinforced LiTaO3 piezoelectric ceramic matrix composites

Densified Al2O3/LiTaO3 (ALT) ceramic matrix composites (CMCs) were fabricated by hot-press sintering in nitrogen atmosphere. Microstructure and mechanical properties of the composites were investigated systematically. High relative density (99.5%) can be obtained when the ALT composites hot-press sintered at 1300 °C with a pressure of 25 MPa. TEM investigation shows that the LiTaO3 particles remain ferroelectric and 90° domains are present in LiTaO3 grains. The Al2O3 particles distribute homogeneously in the LiTaO3 matrix. A high strength of 195.6 MPa and toughness of 2.8 MPa·m1/2 were achieved in the sintered ALT composites. The strengthening and toughening mechanisms of the ALT composites were discussed.