EFFECT OF COARSE PARTICLES ON WORK HARDENING IN THE Al-Mn ALLOY

The effects of coarse Al6Mn particles (similar to 3 mu m) on the formation of a deformed microstructure in the Al-0.66mass%Mn binary alloy have been investigated by the tensile test and the microstructure analysis. The coarse particles have less effect on the dislocation migration in the deformation range up to epsilon=0.002. Due to the localization of the dislocations around the coarse particles, the maximum n-value appears in the deformation range around epsilon=0.02. The dislocation cells are formed in the deformation range above epsilon=0.10. In this stage, the localized dislocations around the particles promote annihilation of the dislocations and prevent an increase in the flow stress. For a higher deformation, the subgrains with a high angle boundary form around the coarse particles. As a consequence of these results, the Mn atoms in the coarse Al6Mn particles have a greater effect on the work hardening than those in the matrix as solute atoms.