Local chemical inhomogeneity enables superior strength-ductility-superelasticity synergy in additively manufactured NiTi shape memory alloys

Abstract NiTi shape memory alloys produced via additive manufacturing are suffering low tensile strength, low total elongation, and unstable superelasticity, thus failing to meet the requirements of practical applications. Here, we report an strategy to substantially and synergistically improve the...

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Main Authors: Zhonghan Li, Jixiang Cai, Zhihao Zhao, Ying Yang, Yang Ren, Gang Sha, Lishan Cui, Kaiyuan Yu, Daqiang Jiang, Yao Xiao, Shengcheng Mao, Shijie Hao
Format: Article
Language:English
Published: Nature Portfolio 2025-02-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-025-56775-0
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author Zhonghan Li
Jixiang Cai
Zhihao Zhao
Ying Yang
Yang Ren
Gang Sha
Lishan Cui
Kaiyuan Yu
Daqiang Jiang
Yao Xiao
Shengcheng Mao
Shijie Hao
author_facet Zhonghan Li
Jixiang Cai
Zhihao Zhao
Ying Yang
Yang Ren
Gang Sha
Lishan Cui
Kaiyuan Yu
Daqiang Jiang
Yao Xiao
Shengcheng Mao
Shijie Hao
author_sort Zhonghan Li
collection DOAJ
description Abstract NiTi shape memory alloys produced via additive manufacturing are suffering low tensile strength, low total elongation, and unstable superelasticity, thus failing to meet the requirements of practical applications. Here, we report an strategy to substantially and synergistically improve the strength, ductility, and superelasticity of NiTi produced by laser powder bed fusion through establishing high-density Ni-rich local chemical inhomogeneity (LCI) entities within B2 matrix. Compared with other documented microstructures such as long-range ordered Ni4Ti3 precipitates, the present Ni-rich LCI entities are unique to increase the resistance against dislocation slip, facilitate stress-induced martensitic transformation, and most importantly, relieve local stress concentration around micro-pore defects and entity interfaces. This specialized microstructure endows tensile superelasticity, i.e., tensile ultimate strength of 958.7 MPa, total tensile elongation of 11.2%, superelastic strain exceeding 7%, and superior cyclic stability. The results advance our capabilities in fabricating high-performance superelastic SMAs with complex geometries through additive manufacturing and LCI engineering.
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institution DOAJ
issn 2041-1723
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publishDate 2025-02-01
publisher Nature Portfolio
record_format Article
series Nature Communications
spelling doaj-art-110ef86d830548748f9fad62f9e2cf0b2025-08-20T03:04:07ZengNature PortfolioNature Communications2041-17232025-02-011611810.1038/s41467-025-56775-0Local chemical inhomogeneity enables superior strength-ductility-superelasticity synergy in additively manufactured NiTi shape memory alloysZhonghan Li0Jixiang Cai1Zhihao Zhao2Ying Yang3Yang Ren4Gang Sha5Lishan Cui6Kaiyuan Yu7Daqiang Jiang8Yao Xiao9Shengcheng Mao10Shijie Hao11College of New Energy and Materials, China University of Petroleum-BeijingBeijing Key Laboratory of Microstructure and Property of Advanced Materials, Faculty of Materials and Manufacturing, Beijing University of TechnologySchool of Mechanical Engineering, Tongji UniversityCollege of Chemical Engineering and Environment, China University of Petroleum-BeijingDepartment of Physics, City University of Hong KongSchool of Materials Science and Engineering, Nanjing University of Science and TechnologyCollege of New Energy and Materials, China University of Petroleum-BeijingCollege of New Energy and Materials, China University of Petroleum-BeijingCollege of New Energy and Materials, China University of Petroleum-BeijingSchool of Mechanical Engineering, Tongji UniversityBeijing Key Laboratory of Microstructure and Property of Advanced Materials, Faculty of Materials and Manufacturing, Beijing University of TechnologyCollege of New Energy and Materials, China University of Petroleum-BeijingAbstract NiTi shape memory alloys produced via additive manufacturing are suffering low tensile strength, low total elongation, and unstable superelasticity, thus failing to meet the requirements of practical applications. Here, we report an strategy to substantially and synergistically improve the strength, ductility, and superelasticity of NiTi produced by laser powder bed fusion through establishing high-density Ni-rich local chemical inhomogeneity (LCI) entities within B2 matrix. Compared with other documented microstructures such as long-range ordered Ni4Ti3 precipitates, the present Ni-rich LCI entities are unique to increase the resistance against dislocation slip, facilitate stress-induced martensitic transformation, and most importantly, relieve local stress concentration around micro-pore defects and entity interfaces. This specialized microstructure endows tensile superelasticity, i.e., tensile ultimate strength of 958.7 MPa, total tensile elongation of 11.2%, superelastic strain exceeding 7%, and superior cyclic stability. The results advance our capabilities in fabricating high-performance superelastic SMAs with complex geometries through additive manufacturing and LCI engineering.https://doi.org/10.1038/s41467-025-56775-0
spellingShingle Zhonghan Li
Jixiang Cai
Zhihao Zhao
Ying Yang
Yang Ren
Gang Sha
Lishan Cui
Kaiyuan Yu
Daqiang Jiang
Yao Xiao
Shengcheng Mao
Shijie Hao
Local chemical inhomogeneity enables superior strength-ductility-superelasticity synergy in additively manufactured NiTi shape memory alloys
Nature Communications
title Local chemical inhomogeneity enables superior strength-ductility-superelasticity synergy in additively manufactured NiTi shape memory alloys
title_full Local chemical inhomogeneity enables superior strength-ductility-superelasticity synergy in additively manufactured NiTi shape memory alloys
title_fullStr Local chemical inhomogeneity enables superior strength-ductility-superelasticity synergy in additively manufactured NiTi shape memory alloys
title_full_unstemmed Local chemical inhomogeneity enables superior strength-ductility-superelasticity synergy in additively manufactured NiTi shape memory alloys
title_short Local chemical inhomogeneity enables superior strength-ductility-superelasticity synergy in additively manufactured NiTi shape memory alloys
title_sort local chemical inhomogeneity enables superior strength ductility superelasticity synergy in additively manufactured niti shape memory alloys
url https://doi.org/10.1038/s41467-025-56775-0
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