Effect of heat treatments on the microstructure and mechanical properties of an ultra-high strength martensitic steel fabricated via laser powder bed fusion additive manufacturing

Seede, Raiyan; Zhang, Bing; Whitt, Austin; Picak, Sezer; Gibbons, Sean; Flater, Philip; Elwany, Alaa; Arróyave, Raymundo; Караман, И.

doi:10.1016/j.addma.2021.102255

Cited by 15 publications

(11 citation statements)

References 34 publications

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“…Comparing the chemical composition of the sample with the powder, a slight decrease in carbon content from 0.22 wt.% (powder) to 0.20 wt.% (sample) could be observed. This decarburization can be attributed to the high temperatures during the manufacturing process, which was also reported for the martensitic steel AF9628 by Seede et al [ 28 ]. Figure 9 presents the results on the tempering studies for as-built and tempered (AT) as well as quenched and tempered (QT) specimens.…”

Section: Resultssupporting

confidence: 67%

PBF-LB/M of Low-Alloyed Steels: Bainite-like Microstructures despite High Cooling Rates

Bartels

Novotny

Mohr³

et al. 2022

Materials

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Laser-based powder bed fusion of metals (PBF-LB/M) is an emerging technology with enormous potential for the fabrication of highly complex products due to the layer-wise fabrication process. Low-alloyed steels have recently gained interest due to their wide potential range of applications. However, the correlation between the processing strategy and the material properties remains mostly unclear. The process-inherent high cooling rates support the assumption that a very fine martensitic microstructure is formed. Therefore, the microstructure formation was studied by means of scanning electron microscopy, hardness measurements, and an analysis of the tempering stability. It could be shown that additively manufactured Bainidur AM samples possess a bainitic microstructure despite the high process-specific cooling rates in PBF-LB/M. This bainitic microstructure is characterized by an excellent tempering stability up to temperatures as high as 600 °C. In contrast to this, additively manufactured and martensitic-hardened specimens are characterized by a higher initial hardness but a significantly reduced tempering stability. This shows the potential of manufacturing products from Bainidur AM for high-temperature applications without the necessity of a post-process heat treatment for achieving the desired bainitic microstructure.

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Section: Resultssupporting

confidence: 67%

PBF-LB/M of Low-Alloyed Steels: Bainite-like Microstructures despite High Cooling Rates

Bartels

Novotny

Mohr³

et al. 2022

Materials

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“…Optical micrographs of the three samples are shown in Figure 3a-c. Melt pool structures and heat-affected zones often appear in as-printed samples [32][33][34]. These interesting features have been reported in some studies [32,35] and may disappear after quenching and tempering.…”

Section: Microstructural Analysismentioning

confidence: 81%

“…After solution treatment, the impact energy increased a little, but it decreased sharply after solution treatment followed by ageing treatment. Raiyan [33] et al manufactured ultrahigh strength martensitic steel AF9628 using laser powder bed fusion (LPBF). The Charpy impact toughness of the as-printed sample was approximately 28 J, but it was reduced to 24 J after quenching and tempering heat treatments.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Microstructure and Mechanical Properties of an Ultrahigh Strength Martensitic Steel Fabricated Using Laser Metal Deposition Additive Manufacturing

Wang

Zhang

et al. 2022

Metals

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Ultrahigh strength steels were additively manufactured (AM) using different batches of powders by means of the laser metal deposition (LMD) technique. After quenching and tempering treatments, the microstructures, mechanical properties, and fracture modes of ultrahigh strength steels were investigated by several testing methods. The results demonstrate that martensite and Fe3C cementite were found in the three specimens after quenching and tempering treatments, and the tempered martensite microstructure had a lamellar structure in all specimens. The widths of these martensite lathes were observed to be different for the APHT-1, APHT-2, and APHT-3 samples, and their sizes were 1.92 ± 0.90 μm, 1.87 ± 1.09 μm, and 1.82 ± 0.85 μm, respectively. The martensitic steel exhibited excellent mechanical properties (tensile strength and impact toughness). The yield strength and the ultimate tensile strength of the APHT-3 sample reached 1582 MPa and 1779 MPa, respectively. Moreover, the value of the impact energy for the APHT-1 sample was 46.4 J. In addition, with the changes in the batches of ultrahigh strength steel powders, the fracture mode changed from ductile fracture to brittle fracture under tensile force and impact loads.

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“…Additionally, there are generic issues during PBF-LB (e.g. keyholes pores and lack of fusion defects) that can lead to a reduction in performance when compared to conventionally produced material and induce anisotropic behaviour [5][6][7]. Overall, these issues have put into question the viability of martensitic low-alloy steel when using PBF-LB.…”

Section: Introductionmentioning

confidence: 99%

Development of powder bed fusion – laser beam process for AISI 4140, 4340 and 8620 low-alloy steel

2022

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This study focuses on process development and mechanical property evaluation of AISI 4140, 4340 and 8620 low-alloy steel produced by powder bed fusionlaser beam (PBF-LB). Process development found that increasing the build plate preheating temperature to 180°C improved processability, as it mitigated lack of fusion and cold cracking defects. Subsequent mechanical testing found that the low-alloy steels achieved a high ultimate tensile strength

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Effect of heat treatments on the microstructure and mechanical properties of an ultra-high strength martensitic steel fabricated via laser powder bed fusion additive manufacturing

Cited by 15 publications

References 34 publications

PBF-LB/M of Low-Alloyed Steels: Bainite-like Microstructures despite High Cooling Rates

PBF-LB/M of Low-Alloyed Steels: Bainite-like Microstructures despite High Cooling Rates

Investigation of the Microstructure and Mechanical Properties of an Ultrahigh Strength Martensitic Steel Fabricated Using Laser Metal Deposition Additive Manufacturing

Development of powder bed fusion – laser beam process for AISI 4140, 4340 and 8620 low-alloy steel

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