{"title":"Enhancing fatigue resistance of high-entropy alloy by designing a hierarchically heterogeneous microstructure","authors":"","doi":"10.1016/j.jmrt.2024.09.091","DOIUrl":null,"url":null,"abstract":"<div><p>Fatigue property is an important index for novel high-entropy alloys (HEAs) before their engineering applications. Here we engineer a Al<sub>0·3</sub>CoCrFeNi HEA with hierarchically heterogeneous microstructure by cold rolling and annealing treatment, which includes heterogeneous grains, annealing and deformation twins, residual dislocations and B2 precipitates with different morphologies, sizes and distributions. Stress-life (<em>S–N)</em> tests and characterization techniques including scanning electron microscope (SEM) and transmission electron microscope (TEM) were carried out to investigate fatigue properties as well as corresponding mechanisms. It is found that this HEA possesses good strength-ductility combination (i.e., yield strength of ∼870 MPa, ultimate tensile strength of ∼1060 MPa and ductility of ∼26 %) and fatigue resistance with fatigue ratio of ∼0.46 under stress ratio of −1. This fatigue ratio exceeds those of most reported HEAs. High strength renders the fatigue deformation mainly occurs in deformation twin regions decorated with B2 precipitates. Surface damage morphologies indicate that fatigue cracks initiate from persistent slip band-like shear bands. In addition, microstructural hierarchy results in the deflected fatigue crack propagation path, which is beneficial for the enhancement of fatigue resistance. Present results offer the guidance on future design for high fatigue-resistant HEAs by manipulating heterogeneous microstructure.</p></div>","PeriodicalId":54332,"journal":{"name":"Journal of Materials Research and Technology-Jmr&t","volume":null,"pages":null},"PeriodicalIF":6.2000,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2238785424020970/pdfft?md5=69c3aad10f28d9df9dce2f3f0765cc41&pid=1-s2.0-S2238785424020970-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Materials Research and Technology-Jmr&t","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2238785424020970","RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Fatigue property is an important index for novel high-entropy alloys (HEAs) before their engineering applications. Here we engineer a Al0·3CoCrFeNi HEA with hierarchically heterogeneous microstructure by cold rolling and annealing treatment, which includes heterogeneous grains, annealing and deformation twins, residual dislocations and B2 precipitates with different morphologies, sizes and distributions. Stress-life (S–N) tests and characterization techniques including scanning electron microscope (SEM) and transmission electron microscope (TEM) were carried out to investigate fatigue properties as well as corresponding mechanisms. It is found that this HEA possesses good strength-ductility combination (i.e., yield strength of ∼870 MPa, ultimate tensile strength of ∼1060 MPa and ductility of ∼26 %) and fatigue resistance with fatigue ratio of ∼0.46 under stress ratio of −1. This fatigue ratio exceeds those of most reported HEAs. High strength renders the fatigue deformation mainly occurs in deformation twin regions decorated with B2 precipitates. Surface damage morphologies indicate that fatigue cracks initiate from persistent slip band-like shear bands. In addition, microstructural hierarchy results in the deflected fatigue crack propagation path, which is beneficial for the enhancement of fatigue resistance. Present results offer the guidance on future design for high fatigue-resistant HEAs by manipulating heterogeneous microstructure.
期刊介绍:
The Journal of Materials Research and Technology is a publication of ABM - Brazilian Metallurgical, Materials and Mining Association - and publishes four issues per year also with a free version online (www.jmrt.com.br). The journal provides an international medium for the publication of theoretical and experimental studies related to Metallurgy, Materials and Minerals research and technology. Appropriate submissions to the Journal of Materials Research and Technology should include scientific and/or engineering factors which affect processes and products in the Metallurgy, Materials and Mining areas.