Abstract
Thermal stability of composite materials with the copper matrix has been investigated. Copper powders with median particle size of 60 µm were mixed with 1 and 3 vol.% micro- and nanosized δ-Al₂O₃ particles and then hot extruded. Specimens were thermally treated at temperatures from room temperature up to 1000 °C. After thermal treatment internal friction of the specimens has been measured. The influence of the thermal treatment on the amplitude dependence of the logarithmic decrement has been studied. From the experimental results it can be concluded that nanopowder additions inhibit recrystallization and grain growth while microparticles can stimulate a growth of grains.

Key words
composite materials, thermal treatment, internal friction, nanopowders, recrystallization

Full text not available