Effect of Cutting Crystal Directions on Micro-Defect Evolution of Single Crystal γ-TiAl Alloy with Molecular Dynamics Simulation

Jianhua Li,Yongnian Qi,Chunli Lei,Ruicheng Feng,Haiyang Qiao,Haiyan Li,Maomao Wang

doi:10.3390/met9121278

Jianhua Li, Yongnian Qi + Show 5 more

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https://doi.org/10.3390/met9121278

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Abstract

In this work, the distribution and evolution of micro-defect in single crystal γ-TiAl alloy during nanometer cutting is studied by means of molecular dynamics simulation. Nanometer cutting is performed along two typical crystal directions: [ 1 ¯ 00 ] and [ 1 ¯ 01 ] . A machined surface, system potential energy, amorphous layer, lattice deformation and the formation mechanism of chip are discussed. The results indicate that the intrinsic stacking fault, dislocation loop and atomic cluster are generated below the machined surface along the cutting crystal directions. In particular, the Stacking Fault Tetrahedron (SFT) is generated inside the workpiece when the cutting crystal direction is along [ 1 ¯ 00 ] . However, a “V”-shape dislocation loop is formed in the workpiece along [ 1 ¯ 01 ] . Furthermore, atomic distribution of the machined surface indicates that the surface quality along [ 1 ¯ 00 ] is better than that along [ 1 ¯ 01 ] . In a certain range, the thickness of the amorphous layer increases gradually with the rise of cutting force during nanometric cutting process.

Highlights

With the development of modern industry, nano-processing technology has been widely used in aerospace, biomedical, national defense and military and other high-tech fields [1]
The nanometric cutting process of single crystal γ-TiAl alloy has been studied by molecular dynamics simulation
The arrangement of the lattice is 0◦ or 180◦ to the tool when the cutting direction is along h i

Summary

Introduction

With the development of modern industry, nano-processing technology has been widely used in aerospace, biomedical, national defense and military and other high-tech fields [1]. In the fabrication of nanodevices, the basic understanding of the material removal mechanism and the evolution of defects is becoming more and more important. Nanofabrication involves material deformation of only a few atomic layers of about 2–10 nm, and the removal of atoms is discrete and discontinuous. Since the 1990s, Molecular Dynamics (MD) simulation technology has been successfully applied to study the removal mechanism of various materials [2]. The MD can reveal the phenomena that cannot be observed by the traditional method, and capture the structure of material, position and velocity of atoms

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