Molecular Dynamics Simulation on the Mechanical Strength of One-Component Amorphous Metal Decreasing of Elastic Moduli and Strength Induced by Change of Internal Structure
Molecular Dynamics Simulation on the Mechanical Strength of One-Component Amorphous Metal Decreasing of Elastic Moduli and Strength Induced by Change of Internal Structure
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单组分非晶金属内部结构变化导致弹性模量和强度下降的机械强度的分子动力学模拟
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发表时间：
2009
期刊：
影响因子：
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通讯作者：
A. Nakatani
中科院分区：
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作者：
K. Nakatani;H. Kitagawa;A. Nakatani
对通过分子动力学模拟快速熔化淬火过程获得的非晶态金属进行加载-卸载原子模拟，以获得基本力学性能以及力学性能和原子结构的变化。由超过最大加载点的大预加载产生的亚稳态结构比初始非晶结构更不稳定。大预压导致弹性模量下降。这种下降不能用内部原子结构不均匀变形中单个原子弹性模量的体积平均值来解释。然而，通过将非晶结构视为异质弹性体并进行有限元分析，该解显示出弹性模量下降的趋势。以屈服应力作为最大应力来评价的强度也会因预压而降低，并出现各向异性。静水压缩的强度大于拉伸的强度。预加载引起的力学性能变化与由 13 个原子组成的本征簇的破坏密切相关，通过 Voronoi 多面体分析将其视为二十面体的数量。
Loading-unloading atomic simulations of an amorphous metal which is obtained by a molecular dynamics simulation for the melting-rapid quenching process are performed in order to obtain the fundamental mechanical properties and the changes of mechanical properties and atomic structures. The metastable structures which are created by large preloading exceeding the maximum loading point are more unstable than the initial amorphous structure. The elastic moduli decrease by the large preloading. The decrease is not explained by the volume average of individual atomic elastic moduli in the inhomogeneous deformation of internal atomic structure. However, by dealing the amorphous structure as a heterogeneous elastic body and carrying out a Finite Element Analysis, the solution shows the tendency of decrease in elastic moduli. The strength, which is evaluated by yield stress as the maximum stress, also decreases by preloading and its anisotropy appears. The strength in hydrostatic compression is larger than that in tension. These changes of mechanical properties by preloading are closely related to the destruction of intrinsic clusters composed of 13 atoms, which is viewed as the number of icosahedra by Voronoi polyhedra analysis.