Serrated flow due to dynamic strain ageing (DSA) of solute atoms appears frequently during the deforma-tion of materials. Serrations can be classified according to their shape into types A, B and C etc. [1]. Type A serrations are characterized by a rise above the level of the load-displacement curve, type B serrations appear above or below the general level of the load-displacement curve; while type C serrations fall below the level of an otherwise smooth load-displacement curve. Different types of serrations can occur singly or simultaneously depending on the deformation temperature (T) and strain rate (e). Type A or B serrations appear at low T or high e. They are often found together, type A + B serrations, and correspond to the normal change of critical strain (ec) for the occurrence of serrated flow. On the contrary, type C serrations appear at high T or low e with the inverse change of critical strain [2, 3].
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