The microstructure and stability in a rapidly solidified Al-Fe-Nb-Si alloy were studied by using transmission electron microscopy (TEM) with energy dispersive X-ray spectrometry (EDXS) and X-ray diffraction technique....The microstructure and stability in a rapidly solidified Al-Fe-Nb-Si alloy were studied by using transmission electron microscopy (TEM) with energy dispersive X-ray spectrometry (EDXS) and X-ray diffraction technique. It is shown that the addition of Nb to Al-Fe-Si alloy may increase undercooling of melt, and form the featureless zone structure, the size of the intercellular phases and the distance between intercellulars of Al-Fe-Nb-Si alloy are two times smaller than that of AI-Fe-V-Si alloy under the same conditions. Further, the microstructure of the featureless zone has the better thermal stability after annealing at 623 K for 24 h.展开更多
Zn-Mg-Y and Mg-Zn-Y-Zr ingots with different chemical compositions were; investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The icosahedral phases were found in all alloys studied in p...Zn-Mg-Y and Mg-Zn-Y-Zr ingots with different chemical compositions were; investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The icosahedral phases were found in all alloys studied in present work under the as-cast conditions. There are nearly all quasicrystal phases with some MgZn2 Laves phase in a Zn-28.31Mg-13.80Y alloy (wt pet). After annealing at 400 degrees C for 8 h, the quasicrystal phases transformed to an fee ''W'' phase in an Mg-5.57Zn-1.08Y-0.60Zr alloy (wt pet).展开更多
文摘The microstructure and stability in a rapidly solidified Al-Fe-Nb-Si alloy were studied by using transmission electron microscopy (TEM) with energy dispersive X-ray spectrometry (EDXS) and X-ray diffraction technique. It is shown that the addition of Nb to Al-Fe-Si alloy may increase undercooling of melt, and form the featureless zone structure, the size of the intercellular phases and the distance between intercellulars of Al-Fe-Nb-Si alloy are two times smaller than that of AI-Fe-V-Si alloy under the same conditions. Further, the microstructure of the featureless zone has the better thermal stability after annealing at 623 K for 24 h.
文摘Zn-Mg-Y and Mg-Zn-Y-Zr ingots with different chemical compositions were; investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The icosahedral phases were found in all alloys studied in present work under the as-cast conditions. There are nearly all quasicrystal phases with some MgZn2 Laves phase in a Zn-28.31Mg-13.80Y alloy (wt pet). After annealing at 400 degrees C for 8 h, the quasicrystal phases transformed to an fee ''W'' phase in an Mg-5.57Zn-1.08Y-0.60Zr alloy (wt pet).
