Stress-induced phase transformation and phase boundary sliding in Ti: An atomically resolved in-situ analysis

Kou Z.; Li X.; Huang R.; Yang L.; Yang Y.; Feng T.; Lan S.; Wilde G.; Lai Q.; Tang S.

Zusammenfassung

In-situ tensile experiments on pure Ti were performed in a transmission electron microscope at room temperature. The dynamic process of stress-induced hexagonal closed-packed (hcp) to face-centered cubic (fcc) structural transformation ahead of a crack tip was captured at the atomic level. Intriguingly, a sliding behavior of the ensuing (0001)hcp/(11¯1)fcc phase boundary was observed to further accommodate the plastic deformation until crack initiation. The sliding was accomplished via the successive conservative glide of extended dislocations along the (0001)hcp/(11¯1)fcc phase boundary. A molecular dynamics simulation was carried out to corroborate the experiments and the results confirm the new dislocation-mediated sliding mechanism.