通过给镁中添加稀土元素 Y 和 Ce 获得了具有良好阻燃效果的 Mg-Y-Ce 合金,该合金能在 1 173 K 的高温下暴露于大气中 0.5 h 而不燃烧。扫描电镜和 X 射线衍射分析表明,合金表面生成了具有双层结构的复杂氧化膜:其中外层主要由 Y2O3和 M...通过给镁中添加稀土元素 Y 和 Ce 获得了具有良好阻燃效果的 Mg-Y-Ce 合金,该合金能在 1 173 K 的高温下暴露于大气中 0.5 h 而不燃烧。扫描电镜和 X 射线衍射分析表明,合金表面生成了具有双层结构的复杂氧化膜:其中外层主要由 Y2O3和 MgO 组成,内层则由大量的金属镁和极少量的 MgO,Y2O3组成。高温氧化动力学研究显示,该合金在673 K 和 773 K 时氧化符合抛物线-直线规律,而在 873 K 下则遵循四方规律。展开更多
The microstructure of as-cast Zr60Al15Ni25 bulk metallic glass was investigated by high-resolution transmission electron microscopy. It is found that there exist numerous short-range order regions （SRORs） in the met...The microstructure of as-cast Zr60Al15Ni25 bulk metallic glass was investigated by high-resolution transmission electron microscopy. It is found that there exist numerous short-range order regions （SRORs） in the metallic glass though it is identified to be amorphous by X-ray diffraction method. Furthermore, the amorphous degree shows a close correlation with the microstructure of corresponding mother ingot. The crystallization kinetics was investigated by differential scanning calorimetry under isochronal and isothermal conditions. The results show that the crystallization is triggered by the growth of the pre-existing SRORs and the growth is three-dimension diffusion-controlled. The amorphous degree of Zr60Al15Ni25 bulk metallic glass considerably influences its crystallization kinetics, namely, the more homogeneous distribution of atoms results in a more sluggish nucleation behavior.展开更多
文摘通过给镁中添加稀土元素 Y 和 Ce 获得了具有良好阻燃效果的 Mg-Y-Ce 合金,该合金能在 1 173 K 的高温下暴露于大气中 0.5 h 而不燃烧。扫描电镜和 X 射线衍射分析表明,合金表面生成了具有双层结构的复杂氧化膜:其中外层主要由 Y2O3和 MgO 组成,内层则由大量的金属镁和极少量的 MgO,Y2O3组成。高温氧化动力学研究显示,该合金在673 K 和 773 K 时氧化符合抛物线-直线规律,而在 873 K 下则遵循四方规律。
基金Project (50804032) supported by the National Natural Science Foundation of ChinaProject (2008011046) supported by the Natural Science Foundation of Shanxi Province, ChinaProject (20080321036) supported by the Key Technologies R & D Program of Shanxi Province, China
文摘The microstructure of as-cast Zr60Al15Ni25 bulk metallic glass was investigated by high-resolution transmission electron microscopy. It is found that there exist numerous short-range order regions （SRORs） in the metallic glass though it is identified to be amorphous by X-ray diffraction method. Furthermore, the amorphous degree shows a close correlation with the microstructure of corresponding mother ingot. The crystallization kinetics was investigated by differential scanning calorimetry under isochronal and isothermal conditions. The results show that the crystallization is triggered by the growth of the pre-existing SRORs and the growth is three-dimension diffusion-controlled. The amorphous degree of Zr60Al15Ni25 bulk metallic glass considerably influences its crystallization kinetics, namely, the more homogeneous distribution of atoms results in a more sluggish nucleation behavior.
