梯度微结构对金属玻璃拉伸增韧的影响

Effect of gradient microstructure on the tensile toughening of metallic glasses

本文通过数值模拟分析了梯度微结构对Ti46Zr20V12Cu5Be17金属玻璃(Metallic Glass,MG)拉伸性能的影响。将自由体积理论以UMAT子程序形式导入ABAQUS中,模拟分析MG基体中剪切带的演化。在此模型中,颗粒和初始自由体积被以各种梯度方程的形式分布于MG基体中,对材料模型施加单轴拉伸荷载。结果表明:含有颗粒按凹槽状梯度分布的MG基复合材料拉伸塑性最好,并且变形呈现颈缩现象;对于初始自由体积呈凸形分布的MG塑性被很好改善;当改变自由体积梯度分布程度时,梯度越小,塑性提高越明显;而就颗粒来说,两侧密集区层数越多,变形中越不容易出现穿透试样的主剪切带。

In this contribution,numerical modeling was performed to interpret the effects of gradient microstructure on the tensile behaviors of Ti46 Zr20 V12 Cu5 Be17 metallic glass（MG）.The free volume theory was incorporated into the ABAQUS code as a user material subroutine UMAT,which was used to depict the shear banding evolution in the MG matrix.Particles and initial free volume were assumed to be distributed in form of various gradient functions,and the resulting material models were loaded under uniaxial tension.The results show that the tensile plasticity of MG matrix composites containing groove shape gradient distribution of particle is best,and appear necking deformation during plastic deformation;For the initial free volume containing the convex gradient distribution,MG plastic is improved well;When the free volume gradient distribution span is changed,the smaller gradient span in MG,the more obvious plastic is increased;And as for particles,the number of plies on both sides is more,the main shear zone through in the sample is not easy to appear during plastic deformation.