Effect of repeated laser scanning on the microstructure evolution of carbon-bearing martensitic steel manufactured by laser powder bed fusion: Quenching-partitioning drives carbon-stabilized austenite formation

Kim, Kyu‐Sik; Kim, Young-Kyun; Lee, Kee‐Ahn

doi:10.1016/j.addma.2022.103262

Cited by 1 publication

(1 citation statement)

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“…Compared with the planar grain boundaries in a single phase, the torturous inter-dendritic regions in ferrite-austenite solidification mode are more difficult for the liquid film to wet, suppressing crack propagation [74]. Compared with ferrite and austenite, martensite has limited weldability due to the high carbon content and the body center cubic (BCC) crystal structure, which can lead to hard and brittle martensitic transformation during welding [89]. Preheating and post-weld heat treatment are generally applied to reduce the cooling rate and facilitate the formation of soft phases such as austenite, improving the ductility and toughness.…”

Section: Fe-based Alloysmentioning

confidence: 99%

Alloy design for laser powder bed fusion additive manufacturing: a critical review

Liu,

Zhou,

Liang

et al. 2024

Int. J. Extrem. Manuf.

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Metal additive manufacturing (AM) has been extensively studied in recent decades. Despite the significant progress achieved in manufacturing complex shapes and structures, challenges such as severe cracking when using existing alloys for laser powder bed fusion (L-PBF) AM persisted. This is due to the fact that commercial alloys are primarily designed for conventional casting or forging processes, without considering the fast cooling rates, steep temperature gradients, and multiple thermal cycles of L-PBF. To address this, there is an urgent need to develop novel alloys specifically tailored for L-PBF technologies. This review provides a comprehensive summary of the strategies employed in alloy design for L-PBF. It aims to guide future research on designing novel alloys dedicated to L-PBF instead of adapting the existing alloys for L-PBF. The review begins by discussing the features of L-PBF processes, focusing on rapid solidification and intrinsic heat treatment. Next, the printability of the four main existing alloys (Fe-, Ni-, Al-, and Ti-based alloys) is critically assessed, with a comparison to their conventional weldability. It was found that the weldability criteria are not always applicable in estimating printability. Furthermore, the review presents recent advances in alloy development and associated strategies, categorizing them into crack mitigation-oriented, microstructure manipulation-oriented, and machine learning-assisted approaches. Lastly, an outlook and suggestions are given to highlight the issues that need be addressed in future work.

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Section: Fe-based Alloysmentioning

confidence: 99%