Papers by Keyword: Structural Refinement

Abstract: PZT-PMN ceramic system with presence of MnO2 contents were proposed and prepared using conventional sintering method as for piezoelectric transformer application. Phase formation and several dielectric and piezoelectric parameters were studied as a function of MnO2 concentration. The x-ray diffraction study revealed the tetragonal symmetry for all samples with MnO2 doping. To determine polarization, the P-E hysteresis loop were produced and the results indicated that entering of Mn4+ ions in the ceramic structure created large amount of oxygen vacancies and the consequent was observed as displacement of the loops to E axis. The obtained optimum parameter are d33 = 119 pC/N, kp = 0.207, Qm = 1669, tan = 0.0101, Pr = 20 μm/cm2 and Ec = 10 kV/cm.

Abstract: Structural refinement in interstitial free (IF) steels has been obtained by three different methods: (i) deformation by cold or warm rolling, (ii) martensitic transformation and (iii) a combination of a martensitic transformation and plastic deformation. For all these processes, the refinement is discussed in terms of grain subdivision by high angle boundaries and dislocation boundaries on length scales from the micrometer level to the nanometer dimension. The characteristics of the subdividing boundaries are discussed, leading to the formulation of strength-structural relationship for IF steel in the deformed state.