Effect of Laser Energy on Anisotropic Material Properties of a Novel Austenitic Stainless Steel with a Fine-Grained Microstructure

Laser powder bed fusion (LPBF) provides a novel approach with high complexity and freedom for material processing and design, and its special thermal history endows the material with anisotropic properties. By adding micro-alloying elements Nb and Ti into conventional 316L, the anisotropy of the nov...

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Main Authors: Yurong Wang, Buwei Xiao, Xiaoyu Liang, Jun Zhou, Feng Lin
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Journal of Manufacturing and Materials Processing
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Online Access:https://www.mdpi.com/2504-4494/8/6/298
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author Yurong Wang
Buwei Xiao
Xiaoyu Liang
Jun Zhou
Feng Lin
author_facet Yurong Wang
Buwei Xiao
Xiaoyu Liang
Jun Zhou
Feng Lin
author_sort Yurong Wang
collection DOAJ
description Laser powder bed fusion (LPBF) provides a novel approach with high complexity and freedom for material processing and design, and its special thermal history endows the material with anisotropic properties. By adding micro-alloying elements Nb and Ti into conventional 316L, the anisotropy of the novel austenitic stainless steel fabricated by LPBF, which is related to the laser heat input, was investigated. The refined microstructure of this steel was further strengthened with in situ-generated Nb-, Cr-, and Ti-rich nanoprecipitates at a specific location. The heat input affects the material anisotropy, and a lower heat input leads to stronger anisotropy in this steel. The as-built parts at a low heat input in the horizontal and vertical planes exhibited finer microstructures compared to those fabricated at a high heat input. The epitaxial growth of the grains associated with the thermal gradient resulted in the vertical-section grain size being generally larger than that of the horizontal section. As a result, the low-heat-input parts with a finer grain are also stronger in the horizontal direction, with yield and tensile strengths approaching 0.9 and 1.2 GPa, respectively. Meanwhile, the microstructural changes due to the high heat input imparted a better ductility of parts in different sections (a 3.15% and 4.4% increase in the horizontal and vertical directions, respectively). Its mechanical properties depend mainly on the direction of stress coupled with intergranular friction during deformation in both coarse and fine grains.
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publishDate 2024-12-01
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series Journal of Manufacturing and Materials Processing
spelling doaj-art-d995c65a9dfc43a7a486771b1fa6788b2024-12-27T14:32:56ZengMDPI AGJournal of Manufacturing and Materials Processing2504-44942024-12-018629810.3390/jmmp8060298Effect of Laser Energy on Anisotropic Material Properties of a Novel Austenitic Stainless Steel with a Fine-Grained MicrostructureYurong Wang0Buwei Xiao1Xiaoyu Liang2Jun Zhou3Feng Lin4Department of Mechanical Engineering, Tsinghua University, Beijing 100084, ChinaDepartment of Mechanical Engineering, Tsinghua University, Beijing 100084, ChinaDepartment of Mechanical Engineering, Tsinghua University, Beijing 100084, ChinaSchool of Mechanical Engineering, Guangxi University, Nanning 530004, ChinaDepartment of Mechanical Engineering, Tsinghua University, Beijing 100084, ChinaLaser powder bed fusion (LPBF) provides a novel approach with high complexity and freedom for material processing and design, and its special thermal history endows the material with anisotropic properties. By adding micro-alloying elements Nb and Ti into conventional 316L, the anisotropy of the novel austenitic stainless steel fabricated by LPBF, which is related to the laser heat input, was investigated. The refined microstructure of this steel was further strengthened with in situ-generated Nb-, Cr-, and Ti-rich nanoprecipitates at a specific location. The heat input affects the material anisotropy, and a lower heat input leads to stronger anisotropy in this steel. The as-built parts at a low heat input in the horizontal and vertical planes exhibited finer microstructures compared to those fabricated at a high heat input. The epitaxial growth of the grains associated with the thermal gradient resulted in the vertical-section grain size being generally larger than that of the horizontal section. As a result, the low-heat-input parts with a finer grain are also stronger in the horizontal direction, with yield and tensile strengths approaching 0.9 and 1.2 GPa, respectively. Meanwhile, the microstructural changes due to the high heat input imparted a better ductility of parts in different sections (a 3.15% and 4.4% increase in the horizontal and vertical directions, respectively). Its mechanical properties depend mainly on the direction of stress coupled with intergranular friction during deformation in both coarse and fine grains.https://www.mdpi.com/2504-4494/8/6/298laser powder bed fusionaustenitic stainless steelanisotropymicrostructuremechanical properties
spellingShingle Yurong Wang
Buwei Xiao
Xiaoyu Liang
Jun Zhou
Feng Lin
Effect of Laser Energy on Anisotropic Material Properties of a Novel Austenitic Stainless Steel with a Fine-Grained Microstructure
Journal of Manufacturing and Materials Processing
laser powder bed fusion
austenitic stainless steel
anisotropy
microstructure
mechanical properties
title Effect of Laser Energy on Anisotropic Material Properties of a Novel Austenitic Stainless Steel with a Fine-Grained Microstructure
title_full Effect of Laser Energy on Anisotropic Material Properties of a Novel Austenitic Stainless Steel with a Fine-Grained Microstructure
title_fullStr Effect of Laser Energy on Anisotropic Material Properties of a Novel Austenitic Stainless Steel with a Fine-Grained Microstructure
title_full_unstemmed Effect of Laser Energy on Anisotropic Material Properties of a Novel Austenitic Stainless Steel with a Fine-Grained Microstructure
title_short Effect of Laser Energy on Anisotropic Material Properties of a Novel Austenitic Stainless Steel with a Fine-Grained Microstructure
title_sort effect of laser energy on anisotropic material properties of a novel austenitic stainless steel with a fine grained microstructure
topic laser powder bed fusion
austenitic stainless steel
anisotropy
microstructure
mechanical properties
url https://www.mdpi.com/2504-4494/8/6/298
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