(a) The strain hardening coefficients of copper and aluminum are 0.3 and 0.15, respectively. Discuss the differences in strain hardening behaviors of these materials based on stacking fault energies.
(b) Peierls-Nabarro stress is a measure of lattice resistance to dislocation motion. Write the equation for Peierls-Nabarro stress and explain the effect of (a) dislocation width, (b) interplanar spacing, and (c) atomic density on the magnitude of Peierls-Nabarro stress.
(c) Estimate the theoretical yield strength of pure iron and compare it with the experimental yield strength. Comment on the results. Cite your sources of data used.