Molecular dynamic simulation of Ti3Al brittle fracture behavior

The decohesion energy and the energy of unstable stacking faults for all cracking planes and dislocation slip systems observed experimentally are calculated using the molecular dynamics method with N-body interatomic potentials. A dimensionless parameter characterizing the brittle behavior of the material is calculated for basis, prism, and pyramid planes in terms of the model elaborated by Kelly et.al. and extended by Rice and Thompson. Cleavage in Ti3A1 is due to low decohesion energy values, which facilitates cracking, and high energies of unstable stacking faults, which prevents the formation of a plastic zone and stress relaxation at its top.