Investigation of the mechanical properties and local structural evolution of Ti60Zr10Ta15Si15 bulk metallic glass during tensile deformation: a molecular dynamics study
HL Chen and SP Ju and TY Wu and SH Liu and HT Chen, RSC ADVANCES, 5, 55383-55395 (2015).
Ti60Zr10Ta15Si15 bulkmetallic glass (BMG) has been proven to have potential for use in orthopedicbone fixation devices, and further studies on its structural properties and deformation mechanism under uniaxial tension have been conducted using molecular dynamics (MD) simulations. The Honeycutt-Andersen (HA) index analysis, Voronoi tessellation method and Warren-Cowley short-range order parameter are employed to investigate its structural properties. The results show a high content of icosahedral-like structures, which suggests an amorphous state and a trend for silicon to pair with a metal atom. In its tensile test, the Ti60Zr10Ta15Si15 bulk metallic glass showed good ductility and an estimated Young's modulus of about 93 GPa, which is close to the experimental value. Local strain distribution was used to analyze the deformation mechanism, and the results show that shear bands develop homogeneously, which enhances the plasticity. The Voronoi tessellation analysis and HA index were used to further investigate the plastic/elastic deformation mechanism. The results of the HA analysis show that icosahedral local structures (1551, 1541, 1431) transfer to less dense structures (1422 and 1311), which shows an increase of open volume which can be attributed to the formation of the shear bands. In addition, the Voronoi tessellation analysis also shows a notable change from perfect icosahedra to distorted icosahedra. Further investigation shows the variations of the Voronoi index are mostly the Ti and Si- centered clusters. This suggests that the structures around Ti and Si atoms undergo a severe evolution during the tension process.
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