Uniaxial tensile tests were performed to investigate the temperature and strain rate dependence of yield strength and grain boundary strengthening in Cu/Nb multilayered foils. At room temperature, grain boundary strengthening is observed at a strain rate of 10-4 s-1, with a Hall-Petch slope (kRT) of 193 ? 10 MPa??m1/2 and an intercept (?0) of 107 ? 11 MPa. At 600°C, the Hall-Petch slope for Nb drops markedly as the strain rate decreases from 10-4 s-1 to 10-6 s-1, indicating that grain boundary strengthening is decreasing as strain rate decreases at 600°C. No grain boundary strengthening is predicted for strain rates below 10-6 s-1.
Grain Boundary Strengthening in Copper/Niobium Multilayered Foils as a Function of Temperature and Strain Rate
A. C. Lewis, C. Eberl,
JMR, Band 23, Seiten 376-382 (2008)