Strengthening mechanisms in the nanocrystalline Cu with Al2O3

摘要

Nanocrystalline (nc) Cu materials with Al2O3 dispersoid (1 and 5 vol.% Al2O3) were produced using the powder metallurgy (PM) techniques. The effect of reinforcement weight fraction, deformation temperature and annealing temperature (up to 800 C) on the strength properties and the microstructure was studied. Two strengthening mechanisms were considered at room temperature, strengthening by grain refinements and dispersion strengthening (DS). The strength properties of both nc Cu composites were strongly dependent on deformation temperature and material composition. The main contribution of nanometric Al2O3 particles to the strength of composites at elevated temperatures is probably the strong pinning effect on the grain/crystallite boundaries and preventing of recrystallization process. After annealing at 0.74 T-m both composites were characterized by an excellent stability of strength characteristics.