搜索

x
中国物理学会期刊

键合特征对金属玻璃弹性变形机制的影响

Influence of bonding characteristics on elastic deformation mechanism of metallic glasses

PDF
HTML
导出引用
  • 金属玻璃变形行为的起源被认为是局域结构的重排, 但是变形过程中不同原子键和团簇类型带来的结构响应机制仍然不明. 我们使用同步辐射高能X射线全散射技术结合对分布函数分析方法原位研究了金属-类金属键体系与金属-金属键体系的金属玻璃拉伸变形过程中的局域结构演变. 结果表明, 在拉伸弹性应变状态下, 金属-金属键体系金属玻璃的短程和中程有序结构堆积密度均变得更加松散, 且结构趋于无序化. 在金属-类金属体系中, 虽然短程有序结构的堆积密度在应变作用下整体结构趋于松散, 但是局域原子键的协同重排使其短程有序结构有序度增加, 并且延伸至中程序尺度. 研究发现金属玻璃原子键的类型显著影响了原子间关联长度与局域结构有序度的变化, 进而影响微观结构的非均匀性与变形行为. 研究结果为揭示金属玻璃变形的微观结构起源提供了新的理解.

    The deformations of metallic glasses are generally attributed to the rearrangements of local structures; however, the structural response mechanisms induced by different atomic bond types and cluster motifs during deformation remain unclear. To establish the correlation mechanism between atomic bonding characteristics and local structural evolution during metallic glass deformation, we employ pair distribution function (PDF) analysis of in-situ synchrotron high-energy X-ray total scattering to investigate the local structural evolutions of metallic glasses with Pd77.5Cu6Si16.5 metal-metalloid (M-Met) and Zr59(Cu0.55Fe0.45)33Al8 metal-metal (M-M) bonding during tensile deformation. Under elastic tensile strain, an M-M system exhibits reduced packing density in both short-range order (SRO) and medium-range order (MRO), and this process is dominated by the medium-range ordered structure, with the overall structure tending to disordering. By contrast, although the overall packing density of SRO and MRO in an M-Met system tends to decrease under strain, cooperative rearrangement of local bonds increases the SRO and this ordering extends to the MRO regime. It is found that the bond type significantly affects the changes in interatomic correlation length and local order, thereby modulating microstructural heterogeneity and deformation behavior. These results provide new insight into the microstructural origins of deformation behavior in metallic glasses.

    目录

    返回文章
    返回
    Baidu
    map