Molecular dynamics for nanoindentation in the γ/α2 interfacial strengthening mechanism of a duplex full lamellar TiAl alloy

Abstract

To investigate the effect of the γ/α2 interface on the deformation behavior and mechanical properties of the duplex all-sheet TiAl alloy during the nanoindentation process, simulations were carried out using molecular dynamics methods. The mechanical properties, atomic displacements, microscopic deformation behavior, stress-strain, and microstructure evolution patterns during nanoindentation are systematically analyzed. The results show that the movement of the atoms is impeded by the interface, directing them in a direction parallel to the interface and thus increasing the workpiece's resistance to deformation. The γ/α2 interface will prevent the propagation of dislocations, causing dislocation buildup, increasing the strength of the TiAl alloy and acting as a hardening agent. In addition, it has been found that the presence of interfaces impedes the transfer of stress and causes discontinuities in the stress distribution, the closer the region to the interface, the denser the distribution of high-stress strain atoms and the greater the concentration of the stress.