A preliminary creep study of a bulk nanocrystalline Al-Mg alloy

The high temperature creep behavior of nanocrystalline Al-Mg alloys is studied with the intent of developing a better fundamental understanding of the role of the fine grain boundary particle distribution on the creep processes as well as of the high temperature creep behavior of nanocrystalline materials in general. The primary transient creep behavior suggests that creep of the cryomilled and extruded Al-Mg alloy is of the Class II type similar to that of pure metals deforming in the power law creep regime. However, the stress exponent obtained at 300 °C is higher than the range of stress exponents associated with Class II creep. Grain boundary sliding may be inhibited in the alloy due to dislocation-particle interactions at the grain boundaries.