Microstructure and Deformation Behavior of Additively Manufactured 17–4 Stainless Steel: Laser Powder Bed Fusion vs. Laser Powder Directed Energy Deposition

Autor: P.D. Nezhadfar, Nima Shamsaei, Shuai Shao, Paul R. Gradl
Rok vydání: 2021
Předmět:
Zdroj: JOM. 74:1136-1148
ISSN: 1543-1851
1047-4838
Popis: This study aims to compare the microstructure of 17–4 PH stainless steel (SS) manufactured via laser powder bed fusion (L-PBF) and laser powder directed energy deposition (LP-DED) in non-heat treated (NHT) and heat treated conditions. In addition, the room-temperature tensile behavior of heat-treated L-PBF and LP-DED 17–4 PH SS has been investigated and compared with that of the wrought counterpart with the same heat treatment conditions. The results show that the L-PBF specimens have a finer microstructure (ferrite + lath martensite) than the LP-DED ones (massive ferrite + Widmanstatten ferrite) in NHT condition. Electron backscatter diffraction analysis shows that the L-PBF and LP-DED specimens have twin-based substructure lath martensite after heat treatment. Despite the lower tensile strength of the LP-DED specimens compared with the L-PBF ones, the ductility of peak-aged LP-DED specimens was reduced due to the presence of the δ-ferrite phase having a significant plastic deformation incompatibility with the martensite.
Databáze: OpenAIRE
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