The rate sensitivity and plastic deformation of nanocrystalline tantalum films at nanoscale
1 National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
2 Department of Material Science and Engineering, Nanjing University, Nanjing 210093, People's Republic of China
3 Key Laboratory of Low Dimensional Materials and Application Technology of Ministry of Education, Faculty of Materials and Photoelectronics Physics, Xiangtan University, Xiangtan 411105, People's Republic of China
Nanoscale Research Letters 2011, 6:186 doi:10.1186/1556-276X-6-186Published: 1 March 2011
Nanoindentation creep and loading rate change tests were employed to examine the rate sensitivity (m) and hardness of nanocrystalline tetragonal Ta films. Experimental results suggested that the m increased with the decrease of feature scale, such as grain size and indent depth. The magnitude of m is much less than the corresponding grain boundary (GB) sliding deformation with m of 0.5. Hardness softening behavior was observed for smaller grain size, which supports the GB sliding mechanism. The rate-controlling deformation was interpreted by the GB-mediated processes involving atomic diffusion and the generation of dislocation at GB.