The production of grain oriented lanthanum titanate (La2Ti2O7) ceramics by uniaxial hot-forging process for improved fracture toughness

The layered-structural ceramics, such as lanthanum titanate (La2Ti2O7), have been known for their good electrical and optical properties at high frequencies and temperatures. However, few studies have been conducted on the mechanical properties of these ceramics. The interest in ceramic hot-forging (HF) has been greatly increased recently due to the enhancement in fracture toughness via bridging effect of oriented grains. In this study, grain oriented lanthanum titanate was produced by the hot-forging process. The characterizations of the samples were achieved by density measurement, scanning electron microscopy (SEM), optical microscopy, X-ray diffraction (XRD), Vickers indentation and three-point bending test. According to X-ray diffraction patterns, the orientation factor (f) was found to be 0.73 for certain hot-forging conditions resulting an improved fracture toughness. The improved fracture toughness of La2Ti2O7 (3.2 MPa m1/2) reached to the value of monolithic alumina (Al2O3) between 3 and 4 MPa m1/2.