On the Thermal Stability of Dislocation Cellular Structures in Additively Manufactured Austenitic Stainless Steels: Roles of Heavy Element Segregation and Stacking Fault Energy

Deng, Pu; Yin, Houshang; Song, Miao; Li, Dian; Zheng, Yufeng; Prorok, Barton C.; Lou, Xiaoyuan

doi:10.1007/s11837-020-04427-7

Cited by 36 publications

(27 citation statements)

References 40 publications

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“…3-3. Previous studies have shown that the microstructure of AM 316L SS is stable below 600°C [19][20][21][22][23][24][25][26][27][28].…”

Section: Microstructure Of Heat-treated Rod Specimensmentioning

confidence: 97%

“…Voisin et al [22] found that the overall grain structures of AM 316L SS remained stable up to 800-1000°C and near defect-free grains formed at 1100°C. Deng et al [20] reported full recrystallization of AM 316L SS after annealing at 1065°C and 1150°C. Our results are consistent with these findings.…”

Section: Microstructure Of Heat-treated Rod Specimensmentioning

confidence: 99%

“…Table 3-2 summarizes the measurements of cell/subgrain size and boundary thickness. Deng et al [20] reported that the cellular structure in AM 316L SS remained stable at 600°C but coarsened slightly after annealing at 700°C. The coarsening of cell structures was accompanied by a decrease in hardness in AM 316L SS.…”

Section: Microstructure Of Heat-treated Rod Specimensmentioning

confidence: 99%

“…columnar grains within melt pools, subgranular cellular structures, high density dislocations within cell walls, boundary elemental segregation, and oxide particles distributed both at boundaries and in the matrix [15][16][17][18]. Post-build heat treatments are performed to relieve residual stresses and to produce desired microstructure and improved mechanical properties [19][20][21][22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

“…Thermal annealing at high temperature can cause thermal instability of the microstructure of the as-built AM 316L SS. Several studies have shown that the hardness and room-temperature yield stress drop continuously with increasing annealing temperatures above 600°C, and this strength reduction has been primarily attributed to the coarsening of cell structures [20][21][22]27]. The variations of the as-built microstructure resulting from the variations in processing conditions, feedstock, or even printer types also complicate the understanding of the thermal stability of the microstructure of AM 316L SS.…”

Section: Introductionmentioning

confidence: 99%

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Location-Dependent Mechanical Property Evaluation on Additively Manufacture Materials

Chen

Zhang

et al. 2021

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This report summarizes research activities conducted at Argonne National Laboratory in support of the development, qualification and certification of additively manufactured (AM) metallic components to allow for innovative reactor design and licensing for the Transformational Challenge Reactor (TCR). Focus is on the evaluation of high temperature mechanical properties including creep and fatigue of 316L stainless steel manufactured by the laser powder bed fusion process. Creep behavior of AM 316L stainless steel was evaluated for rods printed by either or a combination of both lasers of the dual-laser system of a Concept Laser-M2 printer to examine the consistency across the build plate. Creep tests were conducted at temperatures of 550, 575, 600, and 650°C and stresses between 175 and 300 MPa using ASTM standard-sized specimens. The effect of heat treatments at different temperatures on creep properties of AM 316L SS was examined to understand the processing-microstructure-property relationship. Fatigue properties of AM 316L SS were investigated for two print geometries (rod and plate) and in two build orientations of printed plates. Locations of specimens in the build were carefully tracked such that the testing data can be directly related to location-specific in situ data to establish links between printing process, post-printing treatment, microstructure and mechanical properties. The work is to support the development of a digital platform informed approach to AM component qualification and certification for nuclear applications.

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“…3-3. Previous studies have shown that the microstructure of AM 316L SS is stable below 600°C [19][20][21][22][23][24][25][26][27][28].…”

Section: Microstructure Of Heat-treated Rod Specimensmentioning

confidence: 97%

Section: Microstructure Of Heat-treated Rod Specimensmentioning

confidence: 99%

Section: Microstructure Of Heat-treated Rod Specimensmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Location-Dependent Mechanical Property Evaluation on Additively Manufacture Materials

Chen

Zhang

et al. 2021

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The Role of Dislocation Type in the Thermal Stability of Cellular Structures in Additively Manufactured Austenitic Stainless Steel

An,

Xiao,

et al. 2024

Advanced Science

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The ultrafine cellular structure promotes the extraordinary mechanical performance of metals manufactured by laser powder‐bed‐fusion (L‐PBF). An in‐depth understanding of the mechanisms governing the thermal stability of such structures is crucial for designing reliable L‐PBF components for high‐temperature applications. Here, characterizations and 3D discrete dislocation dynamics simulations are performed to comprehensively understand the evolution of cellular structures in 316L stainless steel during annealing. The dominance of screw‐type dislocation dipoles in the dislocation cells is reported. However, the majority of dislocations in sub‐grain boundaries (SGBs) are geometrically necessary dislocations (GNDs) with varying types. The disparity in dislocation types can be attributed to the variation in local stacking fault energy (SFE) arising from chemical heterogeneity. The presence of screw‐type dislocations facilitates the unpinning of dislocations from dislocation cells/SGBs, resulting in a high dislocation mobility. In contrast, the migration of SGBs with dominating edge‐type GNDs requires collaborative motion of dislocations, leading to a sluggish migration rate and an enhanced thermal stability. This work emphasizes the significant role of dislocation type in the thermal stability of cellular structures. Furthermore, it sheds light on how to locally tune dislocation structures with desired dislocation types by adjusting local chemistry‐dependent SFE and heat treatment.

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Recrystallization in non-conventional microstructures of 316L stainless steel produced via laser powder-bed fusion: effect of particle coarsening kinetics

et al. 2022

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Alloys processed by laser powder-bed fusion show distinct microstructures composed of dislocation cells, dispersed nanoparticles, and columnar grains. Upon post-build annealing, such alloys show sluggish recrystallization kinetics compared to the conventionally processed counterpart. To understand this behavior, AISI 316L stainless steel samples were constructed using the island scan strategy. Rhodonite-like (MnSiO3) nanoparticles and dislocation cells are found within weakly-textured grains in the as-built condition. Upon isothermal annealing at 1150 °C (up to 2880 min), the nucleation of recrystallization occurs along the center of the melt pool, where nuclei sites, high stored elastic energy, and local large misorientation are found in the as-built condition. The low value of the Avrami coefficient (n = 1.16) can be explained based on the non-random distribution of nucleation sites. The local interaction of the recrystallization front with nanoparticles speeds up their coarsening causing the decrease of the Zener-Smith pinning force. This allows the progression of recrystallization in LPBF alloys, although sluggish. These results allow us to understand the progress of recrystallization in LPBF 316L stainless steel, shedding light on the nucleation mechanisms and on the competition between driving and dragging pressures in non-conventional microstructures. They also help to understand the most relevant microstructural aspects applicable for tuning microstructures and designing new LPBF alloys. Graphical abstract

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On the Thermal Stability of Dislocation Cellular Structures in Additively Manufactured Austenitic Stainless Steels: Roles of Heavy Element Segregation and Stacking Fault Energy

Cited by 36 publications

References 40 publications

Location-Dependent Mechanical Property Evaluation on Additively Manufacture Materials

Location-Dependent Mechanical Property Evaluation on Additively Manufacture Materials

The Role of Dislocation Type in the Thermal Stability of Cellular Structures in Additively Manufactured Austenitic Stainless Steel

Recrystallization in non-conventional microstructures of 316L stainless steel produced via laser powder-bed fusion: effect of particle coarsening kinetics

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