Rapid Solidification and Phase Transformations in Additive Manufactured Materials

Abstract

In recent years, additive manufacturing (AM) has emerged as a promising manufacturing technique to enable the production of complex engineering structures with high efficiency and accuracy. Among the important factors establishing AM as a sustainable manufacturing process is the ability to control the microstructures and properties of AM products. In most AM processes, such as laser sintering (LS), laser melting (LM), and laser metal deposition (LMD), rapid solidification and high-temperature phase transformations play primary roles in determining nano- and microstructures, and consequently the mechanical and other properties of AM products. 1 This topic of JOM is dedicated to summarizing the current research efforts in the area of rapid solidification and phase transformations in additively manufactured materials. A brief summary follows below of 10 journal articles in this topic. AM results in microstructures that typically differ from those produced by more conventional processing. Cheruvathur et al. explore the phases and microstructures of laser powder-bed fusion additively manufactured 17-4 precipitation hardenable (PH) stainless steel, including the role of post-build thermal processing. They determined that homogenization effectively eliminates the as-built solidification structure, resulting in 90% martensite and 10% austenite that exhibits similar microhardness values to conventionally wrought-processed 17-4 PH.