A Study on the Microstructure and Mechanical Properties of Improved 25Ni-20Cr Steel via in Situ Testing

To meet the application requirements for structural components in Gen-IV nuclear reactors, it is essential to improve the high-temperature mechanical properties of 25Ni-20Cr (S35140) austenitic stainless steel. In this research, an improved austenitic stainless steel (N-S35140), derived from S35140...

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Main Authors: Penghui Lei, Xiaoyu Ji, Jiahao Chen, Yunhao Huang, Nan Lv, Yulin Fan, Yongchao Hou, Xinsheng Shi, Di Yun
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Nanomaterials
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Online Access:https://www.mdpi.com/2079-4991/15/6/413
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author Penghui Lei
Xiaoyu Ji
Jiahao Chen
Yunhao Huang
Nan Lv
Yulin Fan
Yongchao Hou
Xinsheng Shi
Di Yun
author_facet Penghui Lei
Xiaoyu Ji
Jiahao Chen
Yunhao Huang
Nan Lv
Yulin Fan
Yongchao Hou
Xinsheng Shi
Di Yun
author_sort Penghui Lei
collection DOAJ
description To meet the application requirements for structural components in Gen-IV nuclear reactors, it is essential to improve the high-temperature mechanical properties of 25Ni-20Cr (S35140) austenitic stainless steel. In this research, an improved austenitic stainless steel (N-S35140), derived from S35140 steel, was investigated. The scanning transmission electron microscopy (STEM) results indicate that the addition of titanium (Ti) microalloying elements to S35140 steel led to the precipitation of new strengthening nano phases, including M(C, N), MC, MN and Ti(C, N), in N-S35140. These precipitates effectively compensated for the loss of high-temperature strength resulting from the substantial reduction in carbon content. During the in situ transmission electron microscopy (TEM) compressive process at room temperature, the yield strength of N-S35140 steel is 618.4 MPa. At room temperature, the tensile strength of N-S35140 steel is 638.5 MPa, with a yield strength of 392.8 MPa and an elongation of 32.7%, which surpasses those of S35140 steel at room temperature. N-S35140 steel exhibits a tensile strength of 330.6 MPa, a yield strength of 228.2 MPa, and an elongation of 51.4% during the in situ scanning electron microscopy (SEM) tensile test conducted at 650 °C. As a consequence, the improved N-S35140 steel demonstrates significantly enhanced mechanical properties compared to the original S35140 steel, positioning it as a promising candidate for structural components in Gen-IV nuclear reactors.
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spelling doaj-art-baa424b51dbf4c998a53bf02c64832702025-08-20T01:49:01ZengMDPI AGNanomaterials2079-49912025-03-0115641310.3390/nano15060413A Study on the Microstructure and Mechanical Properties of Improved 25Ni-20Cr Steel via in Situ TestingPenghui Lei0Xiaoyu Ji1Jiahao Chen2Yunhao Huang3Nan Lv4Yulin Fan5Yongchao Hou6Xinsheng Shi7Di Yun8School of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, ChinaSchool of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, ChinaSchool of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, ChinaState Key Laboratory of Advanced Nuclear Energy Technology, Nuclear Power Institute of China, Chengdu 610041, ChinaChina National Heavy Machinery Research Institute Co., Ltd., Xi’an 710018, ChinaChina National Heavy Machinery Research Institute Co., Ltd., Xi’an 710018, ChinaChina National Heavy Machinery Research Institute Co., Ltd., Xi’an 710018, ChinaChina National Heavy Machinery Research Institute Co., Ltd., Xi’an 710018, ChinaSchool of Nuclear Science and Technology, Xi’an Jiaotong University, Xi’an 710049, ChinaTo meet the application requirements for structural components in Gen-IV nuclear reactors, it is essential to improve the high-temperature mechanical properties of 25Ni-20Cr (S35140) austenitic stainless steel. In this research, an improved austenitic stainless steel (N-S35140), derived from S35140 steel, was investigated. The scanning transmission electron microscopy (STEM) results indicate that the addition of titanium (Ti) microalloying elements to S35140 steel led to the precipitation of new strengthening nano phases, including M(C, N), MC, MN and Ti(C, N), in N-S35140. These precipitates effectively compensated for the loss of high-temperature strength resulting from the substantial reduction in carbon content. During the in situ transmission electron microscopy (TEM) compressive process at room temperature, the yield strength of N-S35140 steel is 618.4 MPa. At room temperature, the tensile strength of N-S35140 steel is 638.5 MPa, with a yield strength of 392.8 MPa and an elongation of 32.7%, which surpasses those of S35140 steel at room temperature. N-S35140 steel exhibits a tensile strength of 330.6 MPa, a yield strength of 228.2 MPa, and an elongation of 51.4% during the in situ scanning electron microscopy (SEM) tensile test conducted at 650 °C. As a consequence, the improved N-S35140 steel demonstrates significantly enhanced mechanical properties compared to the original S35140 steel, positioning it as a promising candidate for structural components in Gen-IV nuclear reactors.https://www.mdpi.com/2079-4991/15/6/413Gen-IV nuclear reactorsN-S35140 austenitic steelmechanical propertiesTEM in situ compressive testSEM in situ tensile test
spellingShingle Penghui Lei
Xiaoyu Ji
Jiahao Chen
Yunhao Huang
Nan Lv
Yulin Fan
Yongchao Hou
Xinsheng Shi
Di Yun
A Study on the Microstructure and Mechanical Properties of Improved 25Ni-20Cr Steel via in Situ Testing
Nanomaterials
Gen-IV nuclear reactors
N-S35140 austenitic steel
mechanical properties
TEM in situ compressive test
SEM in situ tensile test
title A Study on the Microstructure and Mechanical Properties of Improved 25Ni-20Cr Steel via in Situ Testing
title_full A Study on the Microstructure and Mechanical Properties of Improved 25Ni-20Cr Steel via in Situ Testing
title_fullStr A Study on the Microstructure and Mechanical Properties of Improved 25Ni-20Cr Steel via in Situ Testing
title_full_unstemmed A Study on the Microstructure and Mechanical Properties of Improved 25Ni-20Cr Steel via in Situ Testing
title_short A Study on the Microstructure and Mechanical Properties of Improved 25Ni-20Cr Steel via in Situ Testing
title_sort study on the microstructure and mechanical properties of improved 25ni 20cr steel via in situ testing
topic Gen-IV nuclear reactors
N-S35140 austenitic steel
mechanical properties
TEM in situ compressive test
SEM in situ tensile test
url https://www.mdpi.com/2079-4991/15/6/413
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