Crack Propagation Behavior of Single‐Crystal Titanium Under Cyclic Loading: A Molecular Dynamics Study

ABSTRACT In this study, molecular dynamics (MD) simulations were employed to investigate the crack propagation behavior of single‐crystal titanium with various crystal orientations under cyclic loading. The analysis demonstrates that each crack model displays temporary cyclic hardening and predominant cyclic softening characteristics. The orientation of crack propagation primarily impacts the characteristics of the softening stage, with less influence on the initial hardening stage. A notable orientation correlation is evident in the mechanism of crack propagation, characterized by the presence of various slip modes and deformation twinning (DT) systems. The crack tip deformation behavior obtained from the simulation aligns with the theoretical predictions of linear elastic fracture mechanics (LEFM). The crack growth rate (CGR) and Δ J for different crack models show good correlation, and both the crack propagation direction and crack plane orientation affect the characteristics of the Δ J – da / dN curves.