Mg-9Gd-4Y-2Zn-0.5Zr合金的Johnson-Cook本构模型及失效参数研究  

Johnson-Cook Constitutive Model and Failure Parameters of Mg-9Gd-4Y-2Zn-0.5Zr Alloy

作　　者：郅慧栋 郭保全[1,2] 丁宁[1,2] 闫钊鸣 朱家萱 万晨 Zhi Huidong;Guo Baoquan;Ding Ning;Yan Zhaoming;Zhu Jiaxuan;Wan Chen(Intelligent Weapons Research Institute,North University of China,Taiyuan 030051,China;School of Mechanical and Electrical Engineering,North University of China,Taiyuan 030051,China;School of Materials Science and Engineering,North University of China,Taiyuan 030051,China;College of Missile Engineering,Rocket Force University of Engineering,Xi’an 710051,China)

机构地区：[1]中北大学智能武器研究院,山西太原030051 [2]中北大学机电工程学院,山西太原030051 [3]中北大学材料科学与工程学院,山西太原030051 [4]火箭军工程大学导弹工程学院,陕西西安710051

出　　处：《稀有金属材料与工程》2025年第3期714-721,共8页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(52205428);中国博士后科学基金(2024M754274);山西省应用基础研究计划(202303021212180,20210302124206);山西省科技创新领军人才团队专项(202204051002001)。

摘　　要：研究了Mg-9Gd-4Y-2Zn-0.5Zr合金在不同应变率下的力学行为和断裂失效行为,开展了基于Johnson-Cook(J-C)本构模型和失效模型的参数标定及验证。利用万能试验机对该镁合金进行不同温度下的准静态拉伸试验,并且利用Hopkinson杆开展高应变率(1000~3000 s^(-1))下的动态拉伸试验;根据试验数据对J-C本构模型中的应变率强化项和热软化项进行了修正,并标定相关模型参数。进一步开展数据仿真分析,并对比试验与仿真的断裂位置和真应力-应变曲线,验证失效模型参数的可靠性。使用SEM对镁合金断口微观形貌进行观察,探究温度、应变率对镁合金失效影响的微观行为特征,镁合金在准静态拉伸与动态拉伸过程中断口形貌中均发现了韧窝与解理台阶,为混合断裂机制,且高应变速率下解理台阶稍多,这与镁合金高应变速率下的应变敏感性有关;而在高温拉伸过程中表现为韧性断裂。The mechanical behavior and fracture failure characteristics of Mg-9Gd-4Y-2Zn-0.5Zr alloy at various strain rates were investigated,including parameter calibration and verification based on the Johnson-Cook(J-C)constitutive model and failure model.Quasi-static tensile tests at different temperatures were conducted by a universal testing machine,while dynamic tensile tests at high strain rates(1000–3000 s^(-1))were performed by a Hopkinson bar apparatus.Based on the experimental data,modifications were made to the strain rate hardening and thermal softening terms of the J-C constitutive model were modificated,and relevant model parameters were calibrated.Further numerical simulations were carried out;the fracture locations and true stress-strain curves between experimental and simulated results were compared to validate the reliability of the failure model parameters.The fracture morphology of the magnesium alloy was observed and the microstructural characteristics influencing failure under different temperatures and strain rates were explored.Both dimples and cleavage steps were observed in the fracture morphologies during quasi-static and dynamic tensile processes,indicating a mixed fracture mechanism.Slightly more cleavage steps are found at higher strain rates,which is related to the strain rate sensitivity of the magnesium alloy.In contrast,ductile fracture is predominant during hightemperature tensile tests.

关 键 词：Mg-Gd-Y-Zn-Zr合金 J-C本构模型 J-C失效模型 断裂应变 

分 类 号：TG146.22[一般工业技术—材料科学与工程]