Creep of micron-sized aluminium columns

Micron-sized aluminium columns, produced by focused-ion beam milling, were subjected to compressive creep in a nanoindentation machine using a flat-ended tip to study their time-dependent deformation behaviour at room temperature. At constant load, their strain increased almost linearly with time, with sporadic but large strain bursts superimposed. This represents a form of creep behaviour not known beforehand for aluminium. Strain bursts were also observed to occur during reloading at stresses higher than the first yield stress during initial loading.