Physikalisches Institut, Universität Göttingen, D-37077 Göttingen, Germany.
Nat Mater. 2011 Jun;10(6):439-42. doi: 10.1038/nmat3024.
The nature of non-crystalline materials causes the local potential energy of a cluster of atoms or molecules to vary significantly in space. Different configurations of an ensemble of atoms in a metallic glass lead therefore to a distribution of elastic constants which also changes in space. This is totally different to their crystalline counterparts, where a long-range order exists in space and therefore a much more unified elastic modulus is expected. Using atomic force acoustic microscopy, we present data which show that the local so-called indentation modulus M indeed exhibits a wide distribution on a scale below 10 nm in amorphous PdCuSi, with ΔM/M≈30%. About 10(4) atoms are probed in an individual measurement. Crystallized PdCuSi shows a variation that is 10-30 times smaller and which is determined by the resolution of the microscope and by the polycrystalline structure of the material.
非晶态材料的本质导致原子或分子簇的局部位能在空间中发生显著变化。因此，金属玻璃中原子集合的不同构型导致弹性常数的分布也发生空间变化。这与它们的晶态对应物完全不同，在晶态中，空间存在长程有序，因此预计会有更统一的弹性模量。使用原子力声显微镜，我们提供的数据表明，局部所谓的压痕模量 M 确实在非晶 PdCuSi 中表现出在 10nm 以下的尺度上的宽分布，ΔM/M≈30%。在单个测量中探测到约 10^4 个原子。结晶 PdCuSi 的变化要小 10-30 倍，这由显微镜的分辨率和材料的多晶结构决定。
