Experimental investigation of the fatigue crack growth behaviour in SLM additively manufactured 17-4 PH stainless steel specimens

Selective Laser Melting (SLM) and, in general, the additive manufacturing technologies potentially offer numerous advantages to designers and technologists, such as the reduction of the lead-time of new products and the possibility of producing any kind of complex shape. The performance of components made by means of additive manufacturing under cyclic loading is influenced by crack orientation, porosities, residual stresses, heat treatments, corrosion environments etc. In particular, the crack orientation can influence the fatigue crack propagation. For this reason, in this paper, the fatigue crack propagation behaviour of 17-4 PH stainless steel made by SLM under different crack orientations is presented. The tests were carried out using 6.65 mm thick compact C(T) specimens tested at R = 0.1 and with a frequency of 5 Hz. The main objective was to study the effect of the crack orientation on crack-length vs. number of cycles curves.