{"title":"镁合金有限变形时各向异性韧性损伤的相场模拟","authors":"","doi":"10.1016/j.jma.2022.11.015","DOIUrl":null,"url":null,"abstract":"<div><p>The damage anisotropy of an extruded ZK60 Mg alloy is characterized using tensile tests and scanning electronic microscopy. The accumulation of anisotropic deformations leads to the great differences of the dimple evolution and strains at fracture along different loading directions. To introduce the anisotropic deformation information into the damage constitutive relationship, a thermodynamically consistent phase-field model of ductile damage fully coupled with elastoplastic finite deformations is developed in this study. Using the user-defined constitutive relationship and displacement-temperature coupling element, the finite element simulations are conducted. The results show that: (1) ZK60 Mg alloys presents clear <em>R</em>-value difference in 0°, 45°, and 90° tests of intact specimens. The 45° test possesses the greatest <em>R</em>-value (1.50) and the greatest strain at fracture, however, the <em>R</em>-value for 0° is less than 1, indicating the thinning is preferential. (2) The higher ultimate stress leads to a larger average dimension of the dimples, whereas the higher density correlates with a larger elongation ratio at the fracture. The disappearance of the stress-bearing area indicates that the phase-field assumption on stress degradation is completely compatible with the dimple analysis on fractography. (3) The simulation results of the stress-strain relationships and damage paths correlate well with the experimental ductile damage of magnesium alloys at 200 ℃. Slight errors are basically attributed to the modeling parameters and finite element iteration algorithm. The proposed model presents fine applicability and reliability for the predictions of plastic deformations, ductile damage, and fracture of anisotropic Mg alloys.</p></div>","PeriodicalId":16214,"journal":{"name":"Journal of Magnesium and Alloys","volume":null,"pages":null},"PeriodicalIF":15.8000,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2213956722003085/pdfft?md5=d670fb882b7b445408ebe80c71fa3253&pid=1-s2.0-S2213956722003085-main.pdf","citationCount":"0","resultStr":"{\"title\":\"Phase-field modeling for anisotropic ductile damage of magnesium alloys at finite deformations\",\"authors\":\"\",\"doi\":\"10.1016/j.jma.2022.11.015\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The damage anisotropy of an extruded ZK60 Mg alloy is characterized using tensile tests and scanning electronic microscopy. The accumulation of anisotropic deformations leads to the great differences of the dimple evolution and strains at fracture along different loading directions. To introduce the anisotropic deformation information into the damage constitutive relationship, a thermodynamically consistent phase-field model of ductile damage fully coupled with elastoplastic finite deformations is developed in this study. Using the user-defined constitutive relationship and displacement-temperature coupling element, the finite element simulations are conducted. The results show that: (1) ZK60 Mg alloys presents clear <em>R</em>-value difference in 0°, 45°, and 90° tests of intact specimens. The 45° test possesses the greatest <em>R</em>-value (1.50) and the greatest strain at fracture, however, the <em>R</em>-value for 0° is less than 1, indicating the thinning is preferential. (2) The higher ultimate stress leads to a larger average dimension of the dimples, whereas the higher density correlates with a larger elongation ratio at the fracture. The disappearance of the stress-bearing area indicates that the phase-field assumption on stress degradation is completely compatible with the dimple analysis on fractography. (3) The simulation results of the stress-strain relationships and damage paths correlate well with the experimental ductile damage of magnesium alloys at 200 ℃. Slight errors are basically attributed to the modeling parameters and finite element iteration algorithm. The proposed model presents fine applicability and reliability for the predictions of plastic deformations, ductile damage, and fracture of anisotropic Mg alloys.</p></div>\",\"PeriodicalId\":16214,\"journal\":{\"name\":\"Journal of Magnesium and Alloys\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":15.8000,\"publicationDate\":\"2024-07-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.sciencedirect.com/science/article/pii/S2213956722003085/pdfft?md5=d670fb882b7b445408ebe80c71fa3253&pid=1-s2.0-S2213956722003085-main.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Magnesium and Alloys\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S2213956722003085\",\"RegionNum\":1,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"METALLURGY & METALLURGICAL ENGINEERING\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Magnesium and Alloys","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2213956722003085","RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"METALLURGY & METALLURGICAL ENGINEERING","Score":null,"Total":0}
引用次数: 0
摘要
利用拉伸试验和扫描电子显微镜分析了挤压成型的 ZK60 镁合金的损伤各向异性。各向异性变形的累积导致了不同加载方向上的凹痕演变和断裂应变的巨大差异。为了将各向异性变形信息引入损伤构成关系,本研究开发了一种热力学一致的韧性损伤相场模型,该模型与弹塑性有限变形完全耦合。利用用户定义的构成关系和位移-温度耦合元素,进行了有限元模拟。结果表明(1) ZK60 镁合金在完整试样的 0°、45° 和 90°试验中呈现出明显的 R 值差异。45° 试验具有最大的 R 值(1.50)和最大的断裂应变,然而,0° 的 R 值小于 1,表明变薄是优先的。(2) 极限应力越大,凹痕的平均尺寸就越大,而密度越大,断口处的伸长率就越大。应力承载区的消失表明,应力退化的相场假设与断口凹陷分析完全一致。(3) 应力应变关系和损伤路径的模拟结果与 200 ℃ 下镁合金的韧性损伤实验结果相关性良好。模型参数和有限元迭代算法存在微小误差。所提出的模型对于预测各向异性镁合金的塑性变形、延性损伤和断裂具有良好的适用性和可靠性。
Phase-field modeling for anisotropic ductile damage of magnesium alloys at finite deformations
The damage anisotropy of an extruded ZK60 Mg alloy is characterized using tensile tests and scanning electronic microscopy. The accumulation of anisotropic deformations leads to the great differences of the dimple evolution and strains at fracture along different loading directions. To introduce the anisotropic deformation information into the damage constitutive relationship, a thermodynamically consistent phase-field model of ductile damage fully coupled with elastoplastic finite deformations is developed in this study. Using the user-defined constitutive relationship and displacement-temperature coupling element, the finite element simulations are conducted. The results show that: (1) ZK60 Mg alloys presents clear R-value difference in 0°, 45°, and 90° tests of intact specimens. The 45° test possesses the greatest R-value (1.50) and the greatest strain at fracture, however, the R-value for 0° is less than 1, indicating the thinning is preferential. (2) The higher ultimate stress leads to a larger average dimension of the dimples, whereas the higher density correlates with a larger elongation ratio at the fracture. The disappearance of the stress-bearing area indicates that the phase-field assumption on stress degradation is completely compatible with the dimple analysis on fractography. (3) The simulation results of the stress-strain relationships and damage paths correlate well with the experimental ductile damage of magnesium alloys at 200 ℃. Slight errors are basically attributed to the modeling parameters and finite element iteration algorithm. The proposed model presents fine applicability and reliability for the predictions of plastic deformations, ductile damage, and fracture of anisotropic Mg alloys.
期刊介绍:
The Journal of Magnesium and Alloys serves as a global platform for both theoretical and experimental studies in magnesium science and engineering. It welcomes submissions investigating various scientific and engineering factors impacting the metallurgy, processing, microstructure, properties, and applications of magnesium and alloys. The journal covers all aspects of magnesium and alloy research, including raw materials, alloy casting, extrusion and deformation, corrosion and surface treatment, joining and machining, simulation and modeling, microstructure evolution and mechanical properties, new alloy development, magnesium-based composites, bio-materials and energy materials, applications, and recycling.