{"title":"FCC-BCC phase transformation induced simultaneous enhancement of tensile strength and ductility at high strain rate in high-entropy alloy","authors":"Yong-Chao Wu , Jian-Li Shao","doi":"10.1016/j.ijplas.2023.103730","DOIUrl":null,"url":null,"abstract":"<div><p>FCC-BCC phase transformation-induced plasticity (TRIP) has been extensively studied in high-entropy alloys (HEAs) to customize their mechanical properties through compression/tension loading or thermal fabrication processes. In this study, we employed a combination of molecular dynamics (MD) and Monte-Carlo (MC) simulations to investigate the effects of TRIP on the uniaxial strain tensile deformation of Co<sub>25</sub>Ni<sub>25</sub>Fe<sub>25</sub>Al<sub>7.5</sub>Cu<sub>17.5</sub> HEA. Our results demonstrate that a complete FCC-BCC phase transformation occurs, in accordance with the N-W relationship, resulting in a simultaneous enhancement of strength and ductility. This is attributed to the HEA's significantly low stacking fault energy and pronounced lattice distortion (LD). However, short-range order (SRO) acts as an obstacle on atomic sliding, which further reduces the degree of phase transformation, leading to an increase in Young's modulus but a decrease in ductility. Furthermore, an increase in strain rate can promote the occurrence of the phase transformation to a certain extent but also leads to an increase in the degree of disorder defects. We also found that the HEA maintains excellent thermal stability up to 900 K, but the amount of phase transformation decreases with increasing initial temperature. Our systematic study of FCC-BCC transformation, considering the effects of SRO, LD, strain rate, and temperature, provides insights into tailoring the mechanical properties of HEAs for practical design purposes.</p></div>","PeriodicalId":340,"journal":{"name":"International Journal of Plasticity","volume":"169 ","pages":"Article 103730"},"PeriodicalIF":9.4000,"publicationDate":"2023-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"3","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Plasticity","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0749641923002140","RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, MECHANICAL","Score":null,"Total":0}
引用次数: 3
Abstract
FCC-BCC phase transformation-induced plasticity (TRIP) has been extensively studied in high-entropy alloys (HEAs) to customize their mechanical properties through compression/tension loading or thermal fabrication processes. In this study, we employed a combination of molecular dynamics (MD) and Monte-Carlo (MC) simulations to investigate the effects of TRIP on the uniaxial strain tensile deformation of Co25Ni25Fe25Al7.5Cu17.5 HEA. Our results demonstrate that a complete FCC-BCC phase transformation occurs, in accordance with the N-W relationship, resulting in a simultaneous enhancement of strength and ductility. This is attributed to the HEA's significantly low stacking fault energy and pronounced lattice distortion (LD). However, short-range order (SRO) acts as an obstacle on atomic sliding, which further reduces the degree of phase transformation, leading to an increase in Young's modulus but a decrease in ductility. Furthermore, an increase in strain rate can promote the occurrence of the phase transformation to a certain extent but also leads to an increase in the degree of disorder defects. We also found that the HEA maintains excellent thermal stability up to 900 K, but the amount of phase transformation decreases with increasing initial temperature. Our systematic study of FCC-BCC transformation, considering the effects of SRO, LD, strain rate, and temperature, provides insights into tailoring the mechanical properties of HEAs for practical design purposes.
期刊介绍:
International Journal of Plasticity aims to present original research encompassing all facets of plastic deformation, damage, and fracture behavior in both isotropic and anisotropic solids. This includes exploring the thermodynamics of plasticity and fracture, continuum theory, and macroscopic as well as microscopic phenomena.
Topics of interest span the plastic behavior of single crystals and polycrystalline metals, ceramics, rocks, soils, composites, nanocrystalline and microelectronics materials, shape memory alloys, ferroelectric ceramics, thin films, and polymers. Additionally, the journal covers plasticity aspects of failure and fracture mechanics. Contributions involving significant experimental, numerical, or theoretical advancements that enhance the understanding of the plastic behavior of solids are particularly valued. Papers addressing the modeling of finite nonlinear elastic deformation, bearing similarities to the modeling of plastic deformation, are also welcomed.