On the current research progress of metallic materials fabricated by laser powder bed fusion process: a review

Laser powder bed fusion (LPBF) is the most common metal additive manufacturing technique. Following pre-programmed designs, it employs a high-power density laser source to melt pre-alloyed or mixed powders layer by layer, allowing for complex metallic component fabrication. This technique has recently been utilised to produce superior, near-full-density three-dimensional functional parts for various industrial applications. As the LPBF technology matures, ongoing research is being conducted to increase its viability as a sustainable solution in achieving digital transformation in metallic materials and qualifying new metallic materials for digital products. This review focuses on recent developments in the LPBF technique in terms of process parameters, defects, microstructure evolution, related metallurgical phenomena, and microselective laser melting processing for miniaturised part production. First, considerable attention is given to the related parameters that affect the LPBF process, that is, powder-related and laser-related properties. Second, the metallurgical imperfections related to the LPBF products are described in terms of their types, formation mechanisms, and suppression strategies for these defects. Third, the solidification behaviour, phase transformation, and precipitation during the LPBF processing were systematically investigated. Fourth, the materials implemented in microselective laser melting for three-dimensional microfeature production on various metals are summarised. Finally, the results from this review are summarized, and future research addressing existing difficulties and promoting technical advancements are recommended.