贾伟涛,乐启炽.基于Fields-Backofen方程的镁合金热变形本构模型[J].精密成形工程,2017,9(4):17-24.
JIA Wei-tao,LE Qi-chi.Constitutive Model for Thermal Deformation of Magnesium Alloy Based on Fields-Backofen Equation[J].Journal of Netshape Forming Engineering,2017,9(4):17-24. |
| 基于Fields-Backofen方程的镁合金热变形本构模型 |
| Constitutive Model for Thermal Deformation of Magnesium Alloy Based on Fields-Backofen Equation |
| 投稿时间：2017-05-11 修订日期：2017-07-10 |
| DOI：10.3969/j.issn.1674-6457.2017.04.003 |
| 中文关键词: 构效关系 温度敏感性 热变形行为 本构方程 |
| 英文关键词: structure-activity relationship temperature sensitivity thermal deformation behavior constitutive equation |
| 基金项目:国家重点研发计划（2016YFB0301104） |
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| 摘要点击次数: 4141 |
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| 中文摘要: |
| 目的 研究镁合金热变形行为，建立真实应力与应变、温度及应变速率间的构效关系，以表征多类镁合金的热变形过程。方法 基于Gleeble-1500热模拟实验，定性、定量化分析镁合金热变形的温度敏感性，结合变形曲线的唯象特征，优化并重构Fields-Backofen本构方程以表征镁合金的热变形行为。结果 镁合金热变形过程中，应力关于温度的软化作用可被描述为以e为底的指数函数形式；采用F-B方程表征镁合金热变形行为时，需考虑温度软化作用对该方程进行特定优化；优化后的F-B模型，其形式上为分段式函数，该函数所预测的变形曲线在峰值处存在尖点现象且预测误差较大；利用“离散变形微阶段求解——全阶段整合”的方法，将应变变量植入到应变速率及温度敏感系数，对F-B模型进行重构，可有效解决尖点问题，提高对变形曲线的预测精度。结论 重构后的F-B模型可准确表征AZ31B镁合金的塑性流变行为，并适用于AZ91, AZ80及ZK60等具有与研究合金相似变形特性的镁合金。 |
| 英文摘要: |
| The paper aims to study thermal deformation behaviors of magnesium alloy and establish the structure-activity relationship of different magnesium alloys between true stress, strain, temperature and strain rate. Based on thermal simulation experiments on a Gleeble 1500 simulator, qualitative and quantitative analysis of the temperature sensitivity on thermal deformation behaviors of AZ31B Mg alloys was carried out, and the Fields-Backofen (F-B) constitutive equation used to characterize the thermal deformation of magnesium alloy was optimized and reconstructed by analyzing the phenomenological features of true stress-strain curves. The softening effect of temperature on deformation behaviors during thermal deformation of magnesium alloy could be described as an exponential function for a base of e; when the F-B equation was used to characterize the thermal deformation behaviors of magnesium alloy, the temperature softening effect should be considered to optimize equation; after optimization of the F-B model, the function with the piecewise form resulted in a peak point on the deformation curve and a lager prediction error; with the method of “dividing the whole deformation stage into some micro stages to solve and then achieving full integration", the strain variable was taken into the strain rate and temperature sensitive coefficients to reconstruct the F-B model, which could effectively solve the cusp-point problem, and improve the prediction accuracy of the deformation curves. The reconstructed F-B model can characterize plastic rheological behaviors of the AZ31B magnesium alloy accurately. It was suitable for the AZ91, AZ80 and ZK60 magnesium alloys with similar deformation characteristics. |
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