Activation volume and strain rate sensitivity in plastic deformation of nanocrystalline Ti

Abstract

The mechanical behavior of coarse grained, ultrafine grained and nanocrystalline Ti, which was fabricated on single crystalline Si substrate using a d.c. magnetron sputtering system, were investigated by nanoindentation tests at a range of strain rates; both the strain rate sensitivity and activation volume were obtained. It is demonstrated that the rate controlling mechanisms of plastic deformation for nanocrystalline Ti differ from those in coarse grained and ultrafine grained Ti. The implications of these findings for the mechanical properties of nanocrystalline hcp metals are also discussed.