Limited quasicrystal formation in Zr–Ti–Cu–Ni–Al bulk metallic glasses
Limited quasicrystal formation in Zr–Ti–Cu–Ni–Al bulk metallic glasses
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DOI：
10.1016/j.actamat.2006.05.049
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发表时间：
2006-10
期刊：
影响因子：
9.4
通讯作者：
U. Kühn;K. Eymann;N. Mattern;J. Eckert;A. Gebert;B. Bartusch;L. Schultz
中科院分区：
文献类型：
--
作者：
U. Kühn;K. Eymann;N. Mattern;J. Eckert;A. Gebert;B. Bartusch;L. Schultz
采用铜模铸造法制备了成分为 0⩽x⩽7.5 的大块非晶 Zr62−xTixCu20Ni8Al10 合金。通过差示扫描量热法表征了样品的热稳定性和结晶行为。通过X射线衍射和透射电子显微镜研究结构。测定了铸态样品和选定退火状态的质量密度。铸态玻璃状结构、松弛结构和结晶结构之间密度变化的差异取决于合金的钛含量。玻璃态的堆积密度越高，由于原子迁移率降低，块状玻璃的热稳定性越高。以 0.2at.% 为步长的小 Ti 级配揭示了合金结晶行为的显着变化，涉及所形成相的尺寸和结构。只有 2⩽x<4 的组合物才会在第一个转变步骤中形成亚稳态准晶相。
Bulk amorphous Zr62−xTixCu20Ni8Al10alloys with compositions of 0⩽x⩽7.5 were prepared by copper mold casting. Thermal stability and crystallization behavior of the specimens were characterized by differential scanning calorimetry. Structures were studied by X-ray diffraction and transmission electron microscopy. The mass density of the as-cast samples and of selected annealed states was determined. The difference in density changes, between as-cast glassy, relaxed and crystallized structures, depends on the Ti content of the alloys. The higher the packing density of the glassy state, the higher is the thermal stability of the bulk glass due to a decrease in atomic mobility. Small gradations of Ti in steps of 0.2at.% reveal significant changes in the crystallization behavior of the alloys, concerning the size and the structure of the phases formed. Only compositions with 2⩽x<4 form a metastable quasicrystalline phase during the first transformation step.