A comprehensive review on laser powder bed fusion of steels: Processing, microstructure, defects and control methods, mechanical properties, current challenges and future trends

• Published in: Journal of manufacturing processes Vol. 75; pp. 375 - 414
• Main Authors: Narasimharaju, Shubhavardhan Ramadurga, Zeng, Wenhan, See, Tian Long, Zhu, Zicheng, Scott, Paul, Jiang, Xiangqian, Lou, Shan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.03.2022
• Subjects: Current challenges; Future trends; Laser powder bed fusion process; Mechanical properties; Microstructure; Post-process treatments; Steels; Thermo-physical phenomena; Current challenges; Future trends; Thermo-physical phenomena; Mechanical properties; Post-process treatments; Steels; Microstructure; Laser powder bed fusion process
• ISSN: 1526-6125; 2212-4616
• DOI: 10.1016/j.jmapro.2021.12.033

Laser Powder Bed Fusion process is regarded as the most versatile metal additive manufacturing process, which has been proven to manufacture near net shape up to 99.9% relative density, with geometrically complex and high-performance metallic parts at reduced time. Steels and iron-based alloys are the most predominant engineering materials used for structural and sub-structural applications. Availability of steels in more than 3500 grades with their wide range of properties including high strength, corrosion resistance, good ductility, low cost, recyclability etc., have put them in forefront of other metallic materials. However, LPBF process of steels and iron-based alloys have not been completely established in industrial applications due to: (i) limited insight available in regards to the processing conditions, (ii) lack of specific materials standards, and (iii) inadequate knowledge to correlate the process parameters and other technical obstacles such as dimensional accuracy from a design model to actual component, part variability, limited feedstock materials, manual post-processing and etc. Continued efforts have been made to address these issues. This review aims to provide an overview of steels and iron-based alloys used in LPBF process by summarizing their key process parameters, describing thermophysical phenomena that is strongly linked to the phase transformation and microstructure evolution during solidification, highlighting metallurgical defects and their potential control methods, along with the impact of various post-process treatments; all of this have a direct impact on the mechanical performance. Finally, a summary of LPBF processed steels and iron-based alloys with functional properties and their application perspectives are presented. This review can provide a foundation of knowledge on LPBF process of steels by identifying missing information from the existing literature. [Display omitted] •An introduction to Steels, Additive Manufacturing, Laser Powder Bed Fusion process and their respective applications are presented.•LPBF parameters interplay with respect to complex thermophysical phenomena, solidification theory, evolution of microstructure, and other common issues that arise during LPBF process of steels are outlined.•Formation of Metallurgical defects in LPBF process of steels and their potential control methods are discussed.•Microstructure characteristics, surface texture and wear characteristics, and mechanical properties of as-built vs various post-process treated LPBF steels are critically reviewed.•The current state of art, scientific and technological challenges, and the future trends of LPBF process of steels are prospected.