Fatigue and fracture analysis of Laser powder bed fusion stainless steel alloys: Influence of powder preparation, melt pool geometry, and scanning strategies – A review

Laser powder bed fusion (LPBF) is an advanced additive manufacturing process capable of producing stainless steel components with complex geometries and high design flexibility. However, ensuring reliable fatigue performance under cyclic loading remains a critical concern. Austenitic stainless steels are widely used due to their superior corrosion resistance and stable mechanical properties, yet their fatigue behaviour in additively manufactured conditions is strongly affected by process induced defects, thermal history, and microstructural heterogeneity. This review presents a comprehensive evaluation of recent research on the fatigue and fracture behaviour of stainless steels produced through selective laser melting. It focuses on the role of melt pool characteristics, scanning strategies, and key process parameters in governing fatigue performance. Process variables including laser power, scanning speed, hatch spacing, and layer thickness significantly influence part density, microstructure evolution, and surface integrity, which in turn affect fatigue resistance and corrosion behaviour. Existing studies indicate that powder morphology and particle size distribution play a major role in defect formation, while melt pool stability is critical for improving resistance to crack initiation. Scanning strategies further influence residual stress distribution and crack propagation behaviour. Reported fatigue crack growth rates in LPBF stainless steels generally fall within the range of 10 ⁻⁶ to 10 ⁻⁸ mm per cycle, depending on processing conditions and microstructural refinement. By correlating processing parameters, microstructural features, and fatigue mechanisms, this review provides a clear understanding of crack initiation and propagation in LPBF stainless steels. It identifies key knowledge gaps and suggests future research to develop predictive fatigue life models for reliable use of LPBF stainless steel in aerospace, automotive, and energy sectors.