Ti48Al2Cr2Nb high-temperature alloy consisting of \(\gamma \) and \(\alpha _{2}\) phases, whose room-temperature brittleness limits its use in other lower temperature ranges, has been laser shocked to improve its surface properties. The study of the shock response and plastic deformation behaviour of material then provides further insight into the laser shock peening mechanism. In this paper, the molecular dynamics method and piston impact method are used to simulate laser shock peening of lamellar two-phase TiAl alloys to study the shock response and plastic deformation of material at different shock velocities, as well as the effects of shock velocity and two-phase interface on them. The results show that, in terms of shock response, the location of elastic–plastic wave separation as well as the atomic velocity and stress magnitude are affected by the shock velocity, elastic strain energy and interfacial energy, and some of stresses change significantly at the semi-coherent interface. At lower shock velocities, it is mainly stacking faults and twin boundaries in \(\gamma \) phase that initiate phase transitions across the interface to the \(\alpha _{2}\) phase, whereas at higher velocities, in addition to earlier \(\alpha _{2}\) phase transitions, clustered amorphous atoms and intermediate phases are also observed. The dislocations at the semi-coherent interfaces are affected by both interface type and shock velocity. The mechanical properties of lamellar two-phase TiAl are improved by the effect of laser shock at different shock velocities. These results provide experimental and theoretical guidance for improving the room-temperature properties of two-phase TiAl alloys.
