EBSD and Phase-Field Crystal Simulation Revealed the Inhibition of Al₃Ti on Crack Extention in TC4-2024Al Laminated Composites

In Ti–Al laminated composites, cracks nucleate preferentially at the Al₃Ti layer, but the inhibitory effect of Al₃Ti on crack extension is ignored. Interestingly, by combining experiment and phase-field crystal simulation, we found that the micrometer Al₃Ti particles in the diffusion layer play the role of crack deflection and passivation, which is attributed to the lattice distortion induced by Al₃Ti consumes the energy of the crack in extension. In addition, it is found that the growth process of Al₃Ti is divided into two stages: nucleation stage and growth stage. Compared with the growth stage, the Al₃Ti grains in the nucleation stage are finer in the growth layer. Finer grains show better crack deflection and avoid stress concentration.