Influence of normalizing and tempering treatment on microstructures and mechanical properties of reduced activation ferritic-martensitic steel fabricated by laser directed energy deposition

Reduced activation ferritic-martensitic (RAFM) steel with high strength was prepared by utilizing laser directed energy deposition (L-DED) technology, followed by normalizing and tempering (N&T) to enhance ductility and toughness with underlying mechanisms unraveled through detailed microstructu...

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Main Authors: Zhichen Wang, Linjiang Chai, Shuangshuang Zhong, Chaodan Hu, Tao Yang, Yi Tang, Yu Wu, Xiaolian Tan, Peng Song, Hao Yu, Korukonda L. Murty
Format: Article
Language:English
Published: Elsevier 2025-05-01
Series:Journal of Materials Research and Technology
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Online Access:http://www.sciencedirect.com/science/article/pii/S2238785425009019
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author Zhichen Wang
Linjiang Chai
Shuangshuang Zhong
Chaodan Hu
Tao Yang
Yi Tang
Yu Wu
Xiaolian Tan
Peng Song
Hao Yu
Korukonda L. Murty
author_facet Zhichen Wang
Linjiang Chai
Shuangshuang Zhong
Chaodan Hu
Tao Yang
Yi Tang
Yu Wu
Xiaolian Tan
Peng Song
Hao Yu
Korukonda L. Murty
author_sort Zhichen Wang
collection DOAJ
description Reduced activation ferritic-martensitic (RAFM) steel with high strength was prepared by utilizing laser directed energy deposition (L-DED) technology, followed by normalizing and tempering (N&T) to enhance ductility and toughness with underlying mechanisms unraveled through detailed microstructural analysis. Owing to ultrafast heating and cooling features in laser processing, the L-DEDed specimen exhibits a complicated heterostructure, including ultrafine martensite with high-density of dislocations, a small amount of retained δ-ferrite and austenite, and a few second-phase particles at grain boundaries. After the N&T heat treatment, the L-DED-N&Ted specimen exhibits a more uniform martensitic microstructure with a typical hierarchical feature, along with the presence of dense Cr-rich M23C6-type and Ta-rich MX-type precipitates distributed at the prior austenite grain boundaries and martensitic lath boundaries. The L-DEDed specimen exhibits ultra-high tensile strength (∼1.6 GPa) yet with relatively low elongation (∼6 %) and limited impact toughness (∼20 J/cm2). For the L-DED-N&Ted specimen, its tensile strength decreases but still has a considerably high value of ∼800 MPa, along with largely enhanced elongation (almost doubled) and impact toughness (2.5–3.5 times increased). The high strength of L-DEDed specimen is mainly attributed to strengthening due to dislocations, solid-solution and hetero-deformation, with its lower impact toughness due largely to the existence of δ-ferrite and austenite. The N&T heat treatment produces a more homogeneous microstructure for the RAFM steel along with the elimination of δ-ferrite and austenite. Such microstructural characteristics facilitate suppressing crack initiation and rapid propagation, remarkably enhancing the ductility and impact toughness of the RAFM steel.
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spelling doaj-art-e68f0f08aa954d9f9a7ea3367ecd66722025-08-20T03:09:04ZengElsevierJournal of Materials Research and Technology2238-78542025-05-01363873388510.1016/j.jmrt.2025.04.080Influence of normalizing and tempering treatment on microstructures and mechanical properties of reduced activation ferritic-martensitic steel fabricated by laser directed energy depositionZhichen Wang0Linjiang Chai1Shuangshuang Zhong2Chaodan Hu3Tao Yang4Yi Tang5Yu Wu6Xiaolian Tan7Peng Song8Hao Yu9Korukonda L. Murty10College of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, ChinaCollege of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, China; Corresponding author.College of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, ChinaCollege of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, ChinaCollege of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, ChinaCollege of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054, ChinaScience and Technology on Reactor Fuel and Materials Laboratory, Nuclear Power Institute of China, Chengdu, Sichuan, 610213, China; Corresponding author.Science and Technology on Reactor Fuel and Materials Laboratory, Nuclear Power Institute of China, Chengdu, Sichuan, 610213, ChinaInstitute for Materials Research, Tohoku University, Sendai, 980-8577, JapanInstitute for Materials Research, Tohoku University, Sendai, 980-8577, JapanDepartment of Nuclear Engineering, North Carolina State University, Raleigh, NC, 27695-7909, USAReduced activation ferritic-martensitic (RAFM) steel with high strength was prepared by utilizing laser directed energy deposition (L-DED) technology, followed by normalizing and tempering (N&T) to enhance ductility and toughness with underlying mechanisms unraveled through detailed microstructural analysis. Owing to ultrafast heating and cooling features in laser processing, the L-DEDed specimen exhibits a complicated heterostructure, including ultrafine martensite with high-density of dislocations, a small amount of retained δ-ferrite and austenite, and a few second-phase particles at grain boundaries. After the N&T heat treatment, the L-DED-N&Ted specimen exhibits a more uniform martensitic microstructure with a typical hierarchical feature, along with the presence of dense Cr-rich M23C6-type and Ta-rich MX-type precipitates distributed at the prior austenite grain boundaries and martensitic lath boundaries. The L-DEDed specimen exhibits ultra-high tensile strength (∼1.6 GPa) yet with relatively low elongation (∼6 %) and limited impact toughness (∼20 J/cm2). For the L-DED-N&Ted specimen, its tensile strength decreases but still has a considerably high value of ∼800 MPa, along with largely enhanced elongation (almost doubled) and impact toughness (2.5–3.5 times increased). The high strength of L-DEDed specimen is mainly attributed to strengthening due to dislocations, solid-solution and hetero-deformation, with its lower impact toughness due largely to the existence of δ-ferrite and austenite. The N&T heat treatment produces a more homogeneous microstructure for the RAFM steel along with the elimination of δ-ferrite and austenite. Such microstructural characteristics facilitate suppressing crack initiation and rapid propagation, remarkably enhancing the ductility and impact toughness of the RAFM steel.http://www.sciencedirect.com/science/article/pii/S2238785425009019Reduced activation ferritic/martensitic steelLaser directed energy depositionHeat treatmentTensile propertyImpact toughness
spellingShingle Zhichen Wang
Linjiang Chai
Shuangshuang Zhong
Chaodan Hu
Tao Yang
Yi Tang
Yu Wu
Xiaolian Tan
Peng Song
Hao Yu
Korukonda L. Murty
Influence of normalizing and tempering treatment on microstructures and mechanical properties of reduced activation ferritic-martensitic steel fabricated by laser directed energy deposition
Journal of Materials Research and Technology
Reduced activation ferritic/martensitic steel
Laser directed energy deposition
Heat treatment
Tensile property
Impact toughness
title Influence of normalizing and tempering treatment on microstructures and mechanical properties of reduced activation ferritic-martensitic steel fabricated by laser directed energy deposition
title_full Influence of normalizing and tempering treatment on microstructures and mechanical properties of reduced activation ferritic-martensitic steel fabricated by laser directed energy deposition
title_fullStr Influence of normalizing and tempering treatment on microstructures and mechanical properties of reduced activation ferritic-martensitic steel fabricated by laser directed energy deposition
title_full_unstemmed Influence of normalizing and tempering treatment on microstructures and mechanical properties of reduced activation ferritic-martensitic steel fabricated by laser directed energy deposition
title_short Influence of normalizing and tempering treatment on microstructures and mechanical properties of reduced activation ferritic-martensitic steel fabricated by laser directed energy deposition
title_sort influence of normalizing and tempering treatment on microstructures and mechanical properties of reduced activation ferritic martensitic steel fabricated by laser directed energy deposition
topic Reduced activation ferritic/martensitic steel
Laser directed energy deposition
Heat treatment
Tensile property
Impact toughness
url http://www.sciencedirect.com/science/article/pii/S2238785425009019
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