Papers by Keyword: La Modification

Abstract: Energy efficiency and decreasing emission of greenhouse gasses emerge that the importance of Mg alloys. Mg alloys can begin to supersede the steel and aluminum for structural applications, thanks to the developing of mechanical properties or corrosion resistance of Mg alloys. Rare earth metals such as Gd, Ce, Y and Nd have been utilized at AZ31 Mg alloys for this purpose in recent years. In this study, the effects of La addition and homogenization heat treatment on microstructure, hardness properties and corrosion resistance of AZ31 and modified AZ31 Mg alloys produced by low pressure die casting method were investigated.

Abstract: In this paper, a remelting and diluting (RD) approach was used to fabricate in situ A356-3wt.%TiB₂ composites and the effect of Sr and La on the modification of the composites is investigated in comparison with the conventional flux assisted synthesis (FAS) approach. The microstructure was examined and tensile properties were tested to evaluate the modification efficiency on the composites. The results demonstrated that composites fabricated via RD approach achieve preferable modification by Sr and La due to the higher level of melt cleanliness so as to minimize the Sr-B interaction, in which the eutectic Si which displays a microstructure with globular-fibrous eutectic Si particles. Superior mechanical properties are obtained in the RD composites (especially the elongation) after modified by Sr and La.

Abstract: The oriented La modified PZT thin films were prepared on Pt/Ti/SiO2/Si substrate by the LB technique. The pre-sintering temperatures and the annealing temperatures for La modified PZT were determined by TG-DTA curves and XRD detect results. XRD detection of PZT and PZT with different La amount illustrated the crystal constructions and the effects by modification. The AFM observation of PLZT thin films with organic acid indicated that the LB technique could obtain smooth and flat film with the deposition of PLZT particles within nanometers on substrate. The detection results of the electrical properties indicated that the modification of La had great influence on the electric properties of LB thin film. PLZT thin film by annealing at 650°C had better dielectric constant of 569.2 and dielectric loss of 0.4915 at 5 kHz. And the amount of La of 2% in mass gave the piezoelectric constant of 14pC/N.