اثر ایتربیم روی خواص مکانیکی و ریزساختار آلیاژ آلومینیوم-منیزیم

Effects of Yb on the mechanical properties and microstructures of an Al–Mg alloy

اثر ایتربیم روی خواص مکانیکی و ریزساختار آلیاژ آلومینیوم-منیزیم

ABSTRACT

This paper reported a first study of the effects of Yb on the microstructures and mechanical properties of an extruded Al–Mg alloy. It has been shown that the addition of 0.3 wt.% Yb decreases the mechanical properties of the alloy since Mg- and Yb-containing constituents decrease the concentration of Mg solute atoms in Al matrix, and thus the solution strengthening effect. However, the addition of 1 wt.% Yb substantially improves the mechanical behavior of the alloy because the concentration of Yb solute atoms in Al matrix is high enough to generate solution strengthening effect. The improvement in the mechanical properties is due to the large work-hardening and high dislocation density caused by the interaction between dislocations and Yb and Mg solute atoms. The Yb and Mg atoms inhibit the dynamic recovery and recrystallization of the alloy, thus provide a uniformly distributed dislocation structure with high density.

 

ساخت پودرهای فلزی توسط الکترولیز

Forming metal powders by electrolysis

ساخت پودرهای فلزی توسط الکترولیز

ABSTRACT

Fossil fuels will eventually be replaced by renewables. Currently, the most feasible and efficient way of utilising renewable energy is to convert it to electricity. In response to this change, fossil energy-based pyrometallurgical processes will inevitably shift to electricity driven processes. This chapter considers the feasibility of direct conversion of mineral to metal powder using a new electrochemical method, the FFC Cambridge process. The discussion will be on the background of electrometallurgy and powder metallurgy, the principles of the new process and its application for metal powder production, and the direct route from oxide precursors to alloyed powders.

 

رفتار سینترینگ و خواص دی الکتریکی سرامیک ها

Sintering behavior and dielectric properties of BaTiO3 ceramics with glass addition for internal capacitor of LTCC

رفتار سینترینگ و خواص دی الکتریکی سرامیک های BaTiO3 با افزودنی شیشه برای خازن داخلی LTCC 

ABSTRACT

The addition effects of ZnO–B2O3–SiO2 (ZBS) glass on both the sintering behavior and dielectric properties of BaTiO3 were investigated in developing low-temperature-fired BaTiO3-based ceramics for LTCC devices. X-ray diffractometer (XRD), scanning electron microscopy (SEM), and a dilatometer were used to examine the effect of ZBS glass on BaTiO3 densification and the chemical reaction between the glass and BaTiO3. The results indicate that ZBS glass can be used as a sintering aid to reduce the sintering temperature of BaTiO3 from 1300 to 900 ◦C without secondary phase formation. The dielectric properties of BaTiO3 with ZBS glass sintered at 900 ◦C show a relative density of 95%, a high dielectric constant of 994, and a dielectric loss of 1.6%.