MOLECULAR DYNAMICS, CRACK PROPAGATION ON THE 10*10*10 STRUCTURE OF TYPE B2 TIAL, PARIS LAW

Abstract

In this work, we observed the crack propagation on a 10*10*10 TiAl structure of type B2 with a mesh parameter of 2.824 A; molecular dynamics simulation incorporated in the LAMMPS calculation code with the use of the MEAM potential. To do this, we applied a uniaxial voltage with a maximum value of 30KN along the oz axis for 60s. After several balancing steps, we empirically followed the crack propagation mode according to the Paris law. The TiAl MEAM potential used in this work allowed us to calculate the cohesive energies of different TiAl structures. It was shown that the Type B2 structure is intermediate with a cohesive energy of -4.375eV and a cubic lattice parameter of 3.23A. During equilibration, for the first 30s, we monitored the behaviour of the physical quantities around 300K: kinetic and potential energies, showing overall stable behaviour around the last 20 seconds. Deformation was observed between 30 and 60s at around 300 K. This deformation is the result of the progressive application of stress along the oz axis; pressure is the main physical parameter exploited during this deformation, as is the depth of cracking observed along the oy axis. The evolution of the depth along Oy allowed us to empirically follow the regime mode of the crack propagation, for which we fixed the parameter c=3.5 10-9 , for m=1, we showed that the regime curve is close to the Paris law.