Cyclic deformation behaviour of AlSi10Mg aluminium alloy manufactured by laser-beam powder bed fusion

Abstract

This paper studies the cyclic deformation behaviour of AlSi10Mg aluminium alloy manufactured by laser-beam powder bed fusion for different processing states, namely in the as-built, stress-relieved, and T6 conditions. Low-cycle fatigue tests (Rε = -1) are performed using the single step test method, at room temperature, with a constant strain rate, under strain control mode for strain amplitudes in the range 0.2-1.5%. The main results show that the processing route clearly affects the cyclic stress-strain response of the tested alloy. The strain energy density per cycle of the stress-relived and T6 conditions is much smaller than that of the as-built sate, which is explained by a reduction of the linear portion of hysteresis loops. For lower lives, stress-relieved and T6 conditions led to higher fatigue lives at the same strain amplitude. In addition, on log-log scales, a bi-linear relationship between the plastic strain amplitude and the number of reversals to failure was found for the as-built and stress-relief conditions. On the contrary, for the T6 condition, the data were fitted via a linear function.