Atomistic basis for the plastic yield criterion of metallic glass
Atomistic basis for the plastic yield criterion of metallic glass
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DOI：
10.1038/nmat918
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发表时间：
2003-07-01
期刊：
影响因子：
41.2
通讯作者：
Lund, AC
中科院分区：
文献类型：
--
作者：
Schuh, CA;Lund, AC
由于其无序的原子结构，非晶态金属（称为金属玻璃）与多晶金属相比具有根本不同的变形机制。这些不同的机制使金属玻璃具有高强度，但它们对其他宏观变形性能的影响程度尚不确定。例如，塑性屈服准则的性质是一个争论点，一些研究报告的屈服行为与多晶金属的屈服行为大致一致，而另一些研究则表明存在很大的根本差异。特别是，目前还不清楚是否压力或法向应力的依赖性需要包括在金属玻璃的塑性屈服准则，以及如何从它们的无序结构中产生这种依赖性。在这项工作中，我们提供了一个原子级的解释，在非晶金属的压力依赖的产量，变形的基本单位的基础上。这个简单的模型与新的金属玻璃的原子模拟以及现有的实验数据相比是有利的。
Because of their disordered atomic structure, amorphous metals (termed metallic glasses) have fundamentally different deformation mechanisms compared with polycrystalline metals. These different mechanisms give metallic glasses high strength, but the extent to which they affect other macroscopic deformation properties is uncertain. For example, the nature of the plastic-yield criterion is a point of contention, with some studies reporting yield behaviour roughly in line with that of polycrystalline metals, and others indicating strong fundamental differences. In particular, it is unclear whether pressure- or normal stress-dependence needs to be included in the plastic-yield criterion of metallic glasses, and how such a dependence could arise from their disordered structure,,,. In this work we provide an atomic-level explanation for pressure-dependent yield in amorphous metals, based on an elementary unit of deformation. This simple model compares favourably with new atomistic simulations of metallic glasses, as well as existing experimental data.