Flow stress/strain rate/grain size coupling for fcc nanopolycrystals

Abstract

A Hall–Petch (H–P)-type dependence is demonstrated for reciprocal activation volume measurements for nanocrystalline and conventional grain size, strengthened Ni and Cu materials, consistent with predictions derived from the dislocation pile-up model. The observed H–P dependence indicates that the shear stress for cross-slip must be involved in the full grain size regime for transmission of plastic flow at the grain boundaries of fcc metals.

Acknowledgement

Sincere appreciation is expressed to Dr. S. Venugopal, Indira Gandhi Center for Atomic Research (IGCAR), Kalpakkam, for formatting the figures.