循环荷载作用下金属玻璃的硬化行为研究  

Design of Ultrasonic Fatigue Sample with Planar Section and Experimental Verification through Fatigue Life Testing

作　　者：朱正洪 华军 邢小茹 赵冬 Zhenghong Zhu;Jun Hua;Xiaoru Xing;Dong Zhao(Department of Mechanics,School of Science,Xi'an University of Architecture and Technology,Xi'an,710055)

机构地区：[1]西安建筑科技大学理学院力学系,西安710055

出　　处：《固体力学学报》2024年第3期401-415,共15页Chinese Journal of Solid Mechanics

基　　金：西安建筑科技大学校人才科技基金项目(DB12062)资助。

摘　　要：本文采用分子动力学模拟方法研究二元Cu-Zr金属玻璃在循环荷载作用下的力学行为,并通过荷载-位移曲线、Voronoi指数、局部剪切应变等多种方式分析了不同合金比例和不同加载速率下的硬化行为.结果表明,Cu-Zr金属玻璃的屈服能力随Cu含量的增加而增加,主要是由于Cu含量高的金属玻璃有着更多的短程有序结构.四种不同比例的金属玻璃经过循环荷载诱导后,大深度压痕下的平均硬度比单次压痕下的平均硬度分别增加了1.86%~3.17%.循环过程中剪切带的产生和累积,以及压头下方区域的平均原子体积减少,使得结构更加紧密,从而可以抵抗进一步的变形,这是导致硬化行为的主要因素.采用不同加载速率对Cu50Zr50金属玻璃进行单次压痕和循环压痕,加载速率越高,金属玻璃的平均硬度越高,硬化效应也越明显.This study investigates the mechanical behavior of binary Cu-Zr metallic glass under cyclic loading using the molecular dynamics simulation method.Firstly,simulations of single indentation are performed on metallic glasses with four different alloy ratios(Cu50Zr50,Cu54Zr46,Cu60Zr40,and Cu64Zr36),obtaining their corresponding force-depth curves.The evolution of their microstructures is analyzed using Voronoi indices.To further reveal the hardening mechanism of the metallic glasses under cyclic loading with different alloy ratios and loading rates,the hardness,average atomic volume,residual indentation depth,local shear strain and large strain atoms involved in indentation are analyzed.The results indicate that the yield capacity of metallic glass increases with the Cu content under different alloy ratios,primarily due to a higher Cu content resulting in more short-range ordered structures,thus enhancing the yield capacity.Simulation results also show that after cyclic loading,the average hardness at large depth indentation of metallic glass with the four different alloy ratios increases by 1.86%to 3.17%compared to that of single indentation.The generation and accumulation of shear bands during the cyclic process,as well as the decrease in the average atomic volume in the region beneath the indenter,lead to a denser structure,effectively resisting further deformation and serving as the main factors contributing to the hardening effect.After cyclic indentation of Cu50Zr50 metallic glass at different loading speeds(80m/s,100m/s,150m/s),it is found that the higher the loading rate,the more micro-plastic deformation,residual indentation depth and large strain atoms in the matrix.This leads to a higher average hardness and a more pronounced hardening effect in the metallic glass.The above work not only contributes to a better understanding of the plastic deformation mechanism of binary Cu-Zr metallic glass under cyclic loading,but also provides reference data for potential applications and the design of new nanostructur

关 键 词：金属玻璃 循环荷载 硬化效应 剪切带 分子动力学模拟 

分 类 号：TG139.8[一般工业技术—材料科学与工程]