Nano-crystalline elemental iron powder was successfully formed by high-energy ball grinding.The x-ray diffraction,transmission electron microscopy and Mdssbauer spectroscopy were employed to follow the structure chang...Nano-crystalline elemental iron powder was successfully formed by high-energy ball grinding.The x-ray diffraction,transmission electron microscopy and Mdssbauer spectroscopy were employed to follow the structure changes in the process of mechanical grinding with milling time.The thermal stability of nanocrystalline iron powder was also studied by differential scanning calorimetry.The results showed that the grain size reduces drastically at the initial stage of the milling and reaches 6nm after 40h milling.The broadening of Mdssbauer spectrum is attributed to the large fraction of iron atoms existing at the interfaces for the powder milled.展开更多
Amorphous Al_(80)Fe_(20) powder which can hardly be obtained using conventional rapid quenching technique was directly prepared from crystalline Fe and A1 powders by means of mechanical alloying process.The amorphizat...Amorphous Al_(80)Fe_(20) powder which can hardly be obtained using conventional rapid quenching technique was directly prepared from crystalline Fe and A1 powders by means of mechanical alloying process.The amorphization process was examined by X-ray analysis and Mssbauer spectroscopy,and the thermal behaviour was studied by DSC.The results show that the rate of amorphization is controlled by the diffusion reaction at the interfaces and changes with the milling time.The effect of milling conditions on amorphization by mechanical alloying was al- so investigated.展开更多
基金Supported by the National Natural Science Foundation of China。
文摘Nano-crystalline elemental iron powder was successfully formed by high-energy ball grinding.The x-ray diffraction,transmission electron microscopy and Mdssbauer spectroscopy were employed to follow the structure changes in the process of mechanical grinding with milling time.The thermal stability of nanocrystalline iron powder was also studied by differential scanning calorimetry.The results showed that the grain size reduces drastically at the initial stage of the milling and reaches 6nm after 40h milling.The broadening of Mdssbauer spectrum is attributed to the large fraction of iron atoms existing at the interfaces for the powder milled.
基金supported by the National Natural Science Foundation of China
文摘Amorphous Al_(80)Fe_(20) powder which can hardly be obtained using conventional rapid quenching technique was directly prepared from crystalline Fe and A1 powders by means of mechanical alloying process.The amorphization process was examined by X-ray analysis and Mssbauer spectroscopy,and the thermal behaviour was studied by DSC.The results show that the rate of amorphization is controlled by the diffusion reaction at the interfaces and changes with the milling time.The effect of milling conditions on amorphization by mechanical alloying was al- so investigated.
