Study on declination angle of diamond indenter on TiAl alloy nanoindentation

In this paper, the molecular dynamics method is used to model TiAl alloy. The influence of the declination angle of the indenter on the nanoindentation of TiAl alloy is discussed. The deformation mechanism of the material during the nanoindentation process is discussed on the atomic scale. The results show that the slope of the load–depth curve increases with the increase in the declination angle of the indenter. When the declination angle of the indenter is 0, 1, 2, 3, and 4, the maximum indentation force is 180, 203, 226, 274, and 329 MPa, respectively. It can be seen that the indentation force increases with the increase in the indentation deflection angle. When the declination angle of the indenter is 0, 1, 2, 3, and 4, the dislocation density inside the model is 5.13 × 10−4/A2, 6.61 × 10−4/A2,1.38 × 10−3/A2, 1.43 × 10−3/A2, and 1.84 × 10−3/A2, respectively. It shows that the larger the declination angle of the indenter, the higher the dislocation density. The shear strain also increases with the increase in the declination angle of the indenter. After the indenter is unloaded, the shear strain does not decrease but diffuses further. Compared with before unloading, the shear strain profile becomes wider and deeper.