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taozhikai

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[资源] science最新一篇金属玻璃长程有序性

Long-Range Topological Order in Metallic Glass

Glass lacks the long-range periodic order that characterizes a crystal. In the Ce75Al25 metallicglass (MG), however, we discovered a long-range topological order corresponding to a singlecrystal of indefinite length. Structural examinations confirm that the MG is truly amorphous,isotropic, and unstrained, yet under 25 gigapascals hydrostatic pressures, every segment of acentimeter-length MG ribbon devitrifies independently into a face-centered cubic (fcc) crystalwith the identical orientation. By using molecular dynamics simulations and synchrotron x-ray
techniques, we elucidate that the mismatch between the large Ce and small Al atoms frustratesthe crystallization and causes amorphization, but a long-range fcc topological order still exists.Pressure induces electronic transition in Ce, which eliminates the mismatch and manifests the topological order by the formation of a single crystal.金属玻璃也被称为非晶态合金，是一种具有特殊性能的新型材料。这种材料比玻璃坚硬、比金属有弹性，兼具两者的优点又克服了它们的弊病。其较高的强度、良好的磁学性能和抗腐蚀能力使其在电子、航空航天、机械、微电子等领域有着广泛的应用价值。用它制成的变压器铁芯具有显著的节能效果，在电子设备中使用这种材料还能起到减轻设备重量、增加有效载荷、增强抗干扰能力的作用。此外，它还能用来制造高尔夫球杆、感应式防盗标签等。

[ Last edited by taozhikai on 2011-6-20 at 22:45 ]

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