Low cycle fatigue behaviour of hot extruded Al–4Mg–1Nd alloy

Abstract

The low cycle fatigue behaviour of the hot extruded Al–4Mg–1Nd alloy has been investigated under those total strain amplitudes ranged from 0·3 to 1·2% at room temperature. The results of the low cycle fatigue experiments show that during the fatigue deformation, the significant cyclic strain hardening and stable cyclic stress response can be noted for the hot extruded Al–4Mg–1Nd alloy. The relationship between elastic and plastic strain amplitudes with reversals to failure shows a monotonic linear behaviour, and can be described by the Basquin and Coffin–Manson equations respectively. It is also observed that at the higher total strain amplitudes of 0·8 to 1·2%, the so called dynamic strain aging takes place during the fatigue deformation of hot extruded Al–4Mg–1Nd alloy. In addition, the observations on the fracture surfaces reveal that under the low cycle fatigue loading condition, the fatigue cracks initiate transgranularly at the free surface of fatigue specimens and propagate in a transgranular mode.