The effect of ball milling and wet blending on the creep behaviour of a particle reinforced 2124 Al-alloy

The creep behaviour of an AW2124 Al-alloy unreinforced and reinforced with 25 vol.% of SiC particles of different sizes is investigated. The materials were produced via powder metallurgy using two powder blending techniques: ball milling and wet blending. The SiC particles are fractured during ball milling resulting in 2 – 3 vol.% of sub-μm SiC particles. The SiC particles in the wet blended composites are in the μm-range. The creep behaviour of the matrices and the ball milled composites is characterized by a low-stress and a high-stress region. In the low-stress region the creep deformation is governed by viscous drag of dislocations, while climb of dislocations dominates in the high-stress region. The high creep resistance exhibited by the ball milled composites is mainly due to the presence of oxide dispersoids introduced during blending of the powders.