枝晶的聚集程度对金属玻璃基复合材料力学行为影响的分子动力学研究  

Effect of degree of aggregation of crystalline dendrites on the mechanical behavior of metallic glass matrix composites based on molecular dynamics simulations

作　　者：奚镓倩 杨帆[1] 张梦菲 XI Jiaqian;YANG Fan;ZHANG Mengfei(School of Aerospace Engineering and Applied Mechanics,Tongji University,Shanghai 200092,China;Shanghai Composites Science and Technology Co.,Ltd.,Shanghai 201112,China)

机构地区：[1]同济大学航空航天与力学学院,上海200092 [2]上海复合材料科技有限公司,上海201112

出　　处：《复合材料学报》2025年第3期1633-1643,共11页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(11772231);冲击与冲击材料科学技术国家重点实验室基金(WDZC2023-5)。

摘　　要：引入第二相可以有效地提高金属玻璃基复合材料的塑性。本文通过大规模分子动力学模拟,研究了枝晶弥散分布在基体中的金属玻璃基复合材料试样在单轴拉伸载荷下的力学行为。结果表明:枝晶的聚集程度显著影响材料中剪切带的行为,并导致不同的材料拉伸塑性。枝晶体积分数较小时,金属玻璃基复合材料的塑性变形由剪切转换区(STZ)原子形成剪切带机制占主导,材料的屈服应力和峰值后应力降总体随枝晶聚集程度的减小而减小;枝晶体积分数较大时,材料塑性变形由枝晶内位错滑移机制占主导,材料的屈服强度和峰值后应力降总体随枝晶聚集程度的减小而增大;在枝晶体积分数中等的情况下,两种机制同时起作用且互相影响,使材料屈服应力和塑性变形能力随枝晶聚集程度变化而呈现复杂非单调的变化趋势。本文工作旨在为具有复杂第二相的金属玻璃基复合材料的设计提供指导。Introducing crystalline dendrites can effectively enhance the plasticity of metallic glass matrix composites.In this study,the mechanical behaviors of numerical samples containing dispersed dendrites under uniaxial tensile loading were studied through large-scale molecular dynamics simulations.The results indicate that the degree of aggregation of the dendrites significantly affects the behavior of shear bands in the materials and ultimately leads to different tensile plasticity.When the dendrite volume fraction is relatively low,the plastic deformation of composites is dominated by the mechanism of shear band formation via the initiation of shear transformation zone(STZ)atoms.Conversely,when the dendrite volume fraction is high,the plastic deformation of the material is primarily governed by dislocation slip within the dendrites.In the case of medium dendrite volume fractions,both mechanisms co-exist and interact with each other,resulting in a complex and non-monotonic trend of the yield stress and plastic deformation capability as the degree of dendrite aggregation changes.This work is aimed at providing guidelines for the design of metallic glass matrix composites with complex second phase dendritic structures.

关 键 词：剪切带 力学性能 金属玻璃 分子动力学 复合材料 

分 类 号：TB330.1[一般工业技术—材料科学与工程] TB333