Gadolinium was prepared by conventional procedures of fluorination, reduction, distillation and solid state electrotransport（SSE）. The electronegativities of the metals were found to have an important influence on t...Gadolinium was prepared by conventional procedures of fluorination, reduction, distillation and solid state electrotransport（SSE）. The electronegativities of the metals were found to have an important influence on the electrotransport process and result of the impurity element. Meanwhile, titanium particles in the distilled gadolinium as major metallic impurities were studied by high resolution transmission electron microscopy（HRTEM） before and after solid state electrotransport. The results showed that impurities especially titanium transported from anode to cathode during SSE. In the metal before SSE, there were impurities of titanium in strip shape or embedded round shape. After SSE processing, titanium particles in the metal smaller than 50 nm in the cathode, but existed 6 to 10 times bigger in the anode.展开更多
The possibility of identifying gunshot residue (GSR) particles produced by non-toxic primers containing only titanium and zinc is a very difficult task using SEM/EDX analysis employed in the analysis of GSR originatin...The possibility of identifying gunshot residue (GSR) particles produced by non-toxic primers containing only titanium and zinc is a very difficult task using SEM/EDX analysis employed in the analysis of GSR originating from primers containing lead, barium and antimony. However, Bauer et al. demonstrated that non-toxic (TieZn) primers form a TiZn2O4 spinel crystalline structure using SEM/EDX with EBSD (Electron Back Scatter Diffraction) and TKD (Transmission Kikuchi Diffraction), whereas GSR originating from gadolinium-doped TieZn primers form a non-crystalline glass phase. Here, a possible explanation of these different phenomena is hypothesized.展开更多
Mg65Cu25Gd10 bulk metallic glass and its carbon nanotube reinforced composite were prepared. Differential scanning calorimeter （DSC） was used to investigate the kinetics of glass transition and crystallization proce...Mg65Cu25Gd10 bulk metallic glass and its carbon nanotube reinforced composite were prepared. Differential scanning calorimeter （DSC） was used to investigate the kinetics of glass transition and crystallization processes. The influence of CNTs addition to the glass matrix on the glass transition and crystallization kinetics was studied. It is shown that the kinetic effect on glass transition and crystallization are preserved for both the monothetic glass and its glass composite. Adding CNTs in to the glass matrix reduces the influence of the heating rate on the crystallization process. In addition, the CNTs increase the energetic barrier for the glass transition. This results in the decrease of GFA. The mechanism of the GFA decrease was also discussed.展开更多
The glass forming ability of Gd-Co-Al ternary alloy systems with a composition ranging from 50% to 70% (molar fraction) for Gd and from 5% to 40% (molar fraction) for Al were investigated by copper mold casting and Gd...The glass forming ability of Gd-Co-Al ternary alloy systems with a composition ranging from 50% to 70% (molar fraction) for Gd and from 5% to 40% (molar fraction) for Al were investigated by copper mold casting and Gd60Co25Al15 bulk glass alloy cylinders with the maximum diameter of 5 mm were obtained. The reduced glass transformation temperature (Tg/Tm) and the distance of supercooling region △Tx are 0.616 and 45 K, respectively for this Gd-Co-Al alloy. The compressive fracture strength (σf) and elastic modulus (E) of Gd-Co-Al glassy alloys are 1 170-1 380 MPa and 59-70 GPa, respectively. The Gd-Al-Co bulk glassy alloys with high glass forming ability and good mechanical properties are promising for the future development as a new type function materials.展开更多
基金Project supported by Major State Basic Research Development Program of China(973 Program:2012CBA01207)the National High Technology Research and Development Program of China(863 Program:2011AA03A409)
文摘Gadolinium was prepared by conventional procedures of fluorination, reduction, distillation and solid state electrotransport（SSE）. The electronegativities of the metals were found to have an important influence on the electrotransport process and result of the impurity element. Meanwhile, titanium particles in the distilled gadolinium as major metallic impurities were studied by high resolution transmission electron microscopy（HRTEM） before and after solid state electrotransport. The results showed that impurities especially titanium transported from anode to cathode during SSE. In the metal before SSE, there were impurities of titanium in strip shape or embedded round shape. After SSE processing, titanium particles in the metal smaller than 50 nm in the cathode, but existed 6 to 10 times bigger in the anode.
文摘The possibility of identifying gunshot residue (GSR) particles produced by non-toxic primers containing only titanium and zinc is a very difficult task using SEM/EDX analysis employed in the analysis of GSR originating from primers containing lead, barium and antimony. However, Bauer et al. demonstrated that non-toxic (TieZn) primers form a TiZn2O4 spinel crystalline structure using SEM/EDX with EBSD (Electron Back Scatter Diffraction) and TKD (Transmission Kikuchi Diffraction), whereas GSR originating from gadolinium-doped TieZn primers form a non-crystalline glass phase. Here, a possible explanation of these different phenomena is hypothesized.
文摘Mg65Cu25Gd10 bulk metallic glass and its carbon nanotube reinforced composite were prepared. Differential scanning calorimeter （DSC） was used to investigate the kinetics of glass transition and crystallization processes. The influence of CNTs addition to the glass matrix on the glass transition and crystallization kinetics was studied. It is shown that the kinetic effect on glass transition and crystallization are preserved for both the monothetic glass and its glass composite. Adding CNTs in to the glass matrix reduces the influence of the heating rate on the crystallization process. In addition, the CNTs increase the energetic barrier for the glass transition. This results in the decrease of GFA. The mechanism of the GFA decrease was also discussed.
文摘The glass forming ability of Gd-Co-Al ternary alloy systems with a composition ranging from 50% to 70% (molar fraction) for Gd and from 5% to 40% (molar fraction) for Al were investigated by copper mold casting and Gd60Co25Al15 bulk glass alloy cylinders with the maximum diameter of 5 mm were obtained. The reduced glass transformation temperature (Tg/Tm) and the distance of supercooling region △Tx are 0.616 and 45 K, respectively for this Gd-Co-Al alloy. The compressive fracture strength (σf) and elastic modulus (E) of Gd-Co-Al glassy alloys are 1 170-1 380 MPa and 59-70 GPa, respectively. The Gd-Al-Co bulk glassy alloys with high glass forming ability and good mechanical properties are promising for the future development as a new type function materials.
