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Microstructure–Property Correlation in a Laser Powder Bed Fusion Processed High‐Strength AF‐9628 Steel
Author(s) -
Agrawal Priyanshi,
Shukla Shivakant,
Thapliyal Saket,
Agrawal Priyanka,
Nene Saurabh S.,
Mishra Rajiv S.,
McWilliams Brandon A.,
Cho Kyu C.
Publication year - 2021
Publication title -
advanced engineering materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.938
H-Index - 114
eISSN - 1527-2648
pISSN - 1438-1656
DOI - 10.1002/adem.202000845
Subject(s) - materials science , lath , microstructure , ductility (earth science) , martensite , dislocation , porosity , alloy , carbide , composite material , yield (engineering) , optical microscope , fusion , grain size , metallurgy , scanning electron microscope , creep , linguistics , philosophy
Laser powder bed fusion additive manufacturing (LPBF‐AM) of a low‐alloy, high‐performance AF‐9628 steel results in exceptionally high strength and good ductility. The reasons for such mechanical properties are investigated through detailed microscopy performed at several length scales. Thus, the characterization of melt pool, porosity, grain morphology, phases, and dislocations is performed in the as‐printed material. The as‐printed material consists of only 0.004 vol% of uniformly distributed porosity, single‐phase martensitic laths with an average lath size of ≈2.5 μm, the absence of carbides indicating interstitial trapping of C atom, and high dislocation density in the martensitic laths. Experimental data through microscopy are then fed in analytical models for calculating strengthening contributions from various strengthening mechanisms. Calculated yield strength agrees well with experimentally determined value, and therefore, activation of various strengthening mechanisms is established in as‐printed AF‐9628.