Effects of Zn content on as-cast microstructure and mechanical properties of Mg-xZn-4Al alloys containing TiC and rare earth elements

The effects of Zn content on the as-cast microstructure and mechanical properties of Mg-xZn-4Al alloys containing TiC and rare earth elements were investigated by optical microscopy (OM), scanning electron microscopy (SEM) analysis, X-ray diffraction (XRD) analysis and tensile test. The results show that Zn content which increased from 8% to 12% does not obviously influence on the alloy phase type of the Mg-xZn-4Al experimental alloys containing 0.25%RE and l%TiC, but with Zn content increasing from 8% to 12%, the amount of Mg32(Al,Zn)49 phase in the as-cast microstructure of the experimental alloys increases and its distribution becomes more continuous. In addition, the Mg-10Zn-4Al alloy containing 0.25%RE and 1TiC has the highest ultimate tensile strength at room temperature and 150℃and highest yield strength and elongation at 150℃. Furthermore, with Zn content increasing from 8% to 12%, the yield strength and elongation of Mg-xZn-4A1 experimental alloys containing 0.25%RE and 1%TiC increase and decrease at room temperature, respectively.

Effect of Cr on high temperature oxidation of TiAl

The oxidation behavior of TiAl-Cr(mole fraction of Cr:0-20%) was investigated at 1 173 K in air. The microstructure and composition of the oxide scale were studied by X-ray diffractometry(XRD), scanning electron microscopy(SEM) and electro-probe micro-analyses(EPMA). The results show that with the addition of Cr content from 0 to 8%, the oxidation resistance decreases, especially at 3%, which is mainly attributed to the doping effect of Cr3+. TiAl-Cr(mole fraction of Cr:15%-20%) has good oxidation resistance, and the protective alumina layer is preferentially formed on the surface of TiAl alloy, which is due to an increase of mole ratio of Al to Ti in TiAl-Cr alloys.

Corrosion and electrochemical behavior of AZ31D magnesium alloys in sodium chloride

The corrosion and electrochemical behavior of extruded AZ31D magnesium alloys in NaCl solution were investigated using SEM, XRD and electrochemical method. It is found that AZ31D is susceptive to Cl- ion, and the open circuit potential shifts to more negative values with increasing chloride concentration. Pitting occurs at corrosion potential and corrosion area enlarges with enhanced polarization. Tafel slopes of the cathode branches in different testing solution are almost the same. Cl-concentration affects cathode course slightly. High frequency capacitive loops shrink with the increase of Cl- concentration. Corrosion initiates from the grain boundary and spreads to entire surface with time.

Competitive growth of high purity aluminum grains in directional solidification

A self-made directional solidification setup was used to prepare high purity aluminum ingots of 100mm in diameter. The morphology of the growth interface was detected by SEM and AFM, and the grain lattice orientation was detected by XRD. The results indicate that the grains suffer competitive growth under any conditions in experiments. The lattice orientation of the preferred grains is determined by the flow field above the solid-liquid interface. The horizontal lattice position does not change during the growth process. However, the lattice orientation in the growth direction varies with the growth velocity and approaches to [100] gradually during the growth process.

Studies on the Synthesis of Imidazole-metal Complexes and Their Characterization and Binding Mechanism with DNA

公司， Cd 和 Ni 的三 hexakis (咪唑) metallo 建筑群被综合并且分光镜地描绘了。水晶和分子的结构被 X 光检查晶体学分析决定了。金属离子与 MN6 色基有八面的几何学。电气化学的试验性的结果两个都显示那[公司(Im ) 6 ]