Molecular dynamics simulation study on crystal anisotropy of single crystal Mg nano-scratch

In this paper, the anisotropy of crystals during scratching of single crystal magnesium (Mg) nano-scratch is investigated using molecular dynamics simulation. Firstly, the nano-scratch process was studied by taking the surface of Mg(0001) [ 1 ¯ 2 1 ¯ 0 ] as the scratch surface. The Mg( 10 1 ¯ 0 ) [ 1 ¯ 2 1 ¯ 0 ] and Mg( 1 ¯ 2 1 ¯ 0 ) [0001] surfaces are used as scratch surfaces, respectively. The surface morphology, defect evolution and surface wear of single crystal Mg workpieces during the scratching process of different scratched surfaces are studied. And the relationship between surface topography and defect evolution is analyzed. It is found that there is obvious anisotropy in single crystal Mg during the nano-scratch process. When scratching the Mg( 10 1 ¯ 0 ) [ 1 ¯ 2 1 ¯ 0 ] surface, the surface wear amount is almost unchanged when the scratch distance is 0–4 nm. This is found to be related to the appearance of isolated prismatic dislocation loops during scratching. The process is studied and the formation and disappearance of isolated dislocation loops are analyzed.