Perturbed angular correlation studies of uniaxial compressive stressed zinc, titanium, rutile, Ti2AlN, and Nb2AlC

We use the perturbed angular correlation method with In-111-Cd-111 probe atoms to in situ study the changes in the electric field gradient at room temperature of polycrystalline Ti2AlN and Nb2AlC, titanium and zinc, and rutile samples, as a function of cyclic uniaxial compressive loads. The load dependence of the quadrupole coupling constant v(Q) was found to be large in titanium and zinc but small in Ti2AlN, Nb2AlC and rutile. Reversible and irreversible increases in the electric field gradient distribution widths were found under load and after releasing the load, respectively. Annihilation of dislocations, as well as elastic deformation, are considered to contribute to the reversible behavior. The irreversible response must be caused by a permanent increase in dislocation and point defect densities. The deformation induced broadening of the electric field gradient can be recovered by post-annealing of the deformed sample.