Browsing by Author Dinh, Thi Hinh
Showing results [3 - 5] / 5
This study investigated the structure evolution, surface morphology, dielectric properties, ferroelectric properties, piezoelectric properties, and electromechanical strain properties of lead-free (Bi0.5−xLax)(Na0.41K0.09)TiO3 piezoelectric ceramics. All samples were fabricated by a traditional solid-state synthesis. The effects of La3+-isovalent substituted on Bi3+-site of the Bi0.5Na0.41K0.09TiO3 system were examined. The addition of La doping in the Bi0.5Na0.41K0.09TiO3 ceramics induced the second phase of K4Ti3O8 and a crystal structural change from the rhombohedral and tetragonal phase to a pseudocubic phase. All samples show similar grain morphology and dense microstructure with... |
The molecular dynamics simulations have been carried out to investigate the mechanical behaviors of amorphous silicon nitride under the uniaxial tensile deformation. The amorphous silicon nitride was obtained by the cooling process. The network structure of the sample consists of SiNx (x = 3, 4 and 5) units and NSiy (y = 2, 3 and 4) linkages. The stress-strain curve of the sample exhibits the elastic and plastic deformation. The Si-N bond lengths are stretched out in the elastic region and the plastic region I. They are shrunk to the initial state in the plastic region II due to the appearance of the large clusters which contain the overlapping big simplexes with the RS ≥ 2.4 Å. These... |
Multiphase Al2O3 samples are simulated using molecular dynamics method. These samples consist of γ-Al2O3 and α-Al2O3 crystals embedded in a disordered phase matrix. The stress–strain curves of these samples show elastic and plastic deformation. Structural analysis indicates that the AlO bond lengths are stretched and the geometries of the AlOx (x = 4, 5, and 6) units are distorted during tensile deformation. AlO bond breakage causes the transformation of AlOx units; AlO4 increases while AlO6 decreases with increasing strain. The γ-Al2O3 and α-Al2O3 crystals transfer into the disordered phase, while a small number of atoms recrystallize under tensile loads. In plastic deformation, la... |
