Dynamic Characteristics Of The Shear Band In Fe-based Metallic Glasses

The formation and expansion of the shear band carry the plastic deformation of the iron-based metallic glass at room temperature.The rapid softening and expansion of the shear band is the main factor that causes the fracture of the Fe-based metallic glasses.Understanding the mechanism of the formation and propagation of the shear band helps understanding Fe-based metallic glasses plastic deformation mechanism,developing Fe-based metallic glasses with great plasticity.In this paper,the relationship between the serrated flow behavior of Fe-based amorphous alloys and the shear band and plastic deformation is studied from the perspective of nonlinear dynamics.The finite element method is used to simulate the formation and propagation behavior of shear bands under the loading conditions of Fe-based metallic glasses.The main conclusions are as follows:(1)Under the loading conditions with both ends fixed,the Stress-Strain curve of the Fe-based metallic glasses exhibits a serrated flow behavior effect under the action of the shear band,which reflects the intermittent movement behavior of the shear band.Using the dynamic method,it was found that the plastic deformation shear band of ductile Fe-based metallic glasses mostly correspond to the self-organized critical state,while the brittle Fe-based metallic glasses correspond to the chaotic state.(2)Under the limited loading conditions,the stress field of the Fe-based metallic glasses will redistribute before and after the formation of the shear zone,and a new shear zone will be formed in the direction of higher stress perpendicular to the original shear zone.An offset of a few micrometers of shear will result in a non-uniformity of the stress distribution of several tens of megapascals,which is equivalent to the shear softening effect of the original shear band and may lead to the formation of new shear bands.The above conclusions are helpful for understanding the plastic deformation mechanism of Fe-based metallic glasses,understanding the formation mechanism of shear band,and have important significance for improving the plasticity of Fe-based metallic glasses and exploring the large plastic Fe-based amorphous alloys.The text include 33 graph,3 chart and 85 references.