Fatigue characteristics of steels manufactured by selective laser melting

Additive manufacturing is extending its influence on various modern industries, including automobile, aerospace, aviation, and maritime. This is specifically true for selective laser melting since it is capable of manufacturing dense parts from metal and alloy powders. Thus, the performance of materials processed by selective laser melting has become the focus of many studies recently. However, their fatigue endurance is yet to be understood comprehensively, and few studies have been carried out on this topic thus far. The lack of understanding is often attributed to the considerable number of manufacturing parameters, which also hinders employing selective laser melting for typical industrial applications. Among the various materials processed by selective laser melting, steel is one of the most attractive ones to manufacturers due to its broad range of properties and applications. This paper aims to describe the studies carried out on the fatigue properties of diverse types of steel manufactured by selective laser melting. It also reviews the parameters which are recognized to be effective on the fatigue behaviour of these steels. These parameters include building orientation, heat treatment, surface quality, energy density, and service condition of the final product. Recent studies on selective laser melting along with the variety of its influential parameters on the fatigue strength highlight a knowledge gap towards reaching a comprehensive understanding of the fatigue behaviour of steels manufactured by this process. Based on this fact, some of these gaps are discussed as the potential topics for the future studies in the field of additive manufacturing at the end of this review.