Yongyan Li

Effect of titanium, antimony, cerium and carbon nanotubes on the morphology and microhardness of Mg-based icosahedral quasicrystal phase

F or the flrst time, petal-like and spherical Mg-based icosahedral quasicrystal phase (I-phase) were obtained by introducing Ti, Sb, Ce and C nanotubes into Mg-Zn-Y alloy under normal casting conditions. The formation mechanism and stability criterion of spherical I-phase were discussed. The morphology and microhardness of I-phase and their determinants were studied in this paper. The results show that the difierent value of microhardness of I-phase could be attributed to the difierent kinds of the fourth component and its content, and its difierent innate characters. The flnal morphology of icosahedral quasicrystalline (IQC) is decided by the size of critical stable radius Rr, the content of the fourth component and degree of undercooling.

Tailored Dealloying Products of Cu-based Metallic Glasses in Hydrochloric Acid Solutions

Free dealloying of Cu-Hf-Al metallic glasses in HCl electrolytes are studied in this paper. The results show that the electrolyte concentration and dealloying time strongly influence the type of dealloying products. A superficial dealloying happens in diluted HCl electrolytes while a complete dealloying occurs in concentrated HCl electrolytes. The results present that Cu 2 O microparticles with regular morphology can be tailored on glassy surfaces in 0.05 M HCl solution by controlling the dealloying time. Furthermore, the designable products of nanoporous Cu, Cu 2 O nanoplates and CuO microwires can be fabricated in 1.2 M HCl electrolyte with the dealloying time. Due to a big difference of examined Cu-Hf-Al alloys in the electrolyte concentration and dealloying time, one or mixed dealloying products (Cu, Cu 2 O and CuO), which depend on the progress of relative chemical reactions and the different dealloying route, will finally be produced.