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中南大学学报(自然科学版)

Journal of Central South University

第47卷    第4期    总第260期    2016年4月

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文章编号:1672-7207(2016)04-1111-10
BR1500HS超高强度钢本构模型的建立及验证
夏玉峰,纪帅,张严东

(重庆大学 材料科学与工程学院, 重庆,400044)

摘 要: 在Gleeble3500热模拟实验机上,采用等温热拉伸实验对BR1500HS超高强度钢在变形温度为1 023,1 073, 1 123和1 173 K,应变速率为0.01,0.10和1.00 s-1条件下的热流变行为进行研究。根据蠕变理论及实验流动应力曲线确定材料变形激活能、硬化指数等相关材料常数并引入Zener-Hollomon参数。通过位错密度演化模型描述加工硬化和动态回复对流动应力的影响,并建立包含稳态应力σss、屈服应力σ0和动态回复速率系数r这3个参数的本构模型。研究结果表明:由建立的本构模型所绘制的流动应力曲线与实验曲线具有高度一致性,所建立的本构模型能够应用于BR1500HS超高强度钢热拉伸过程的数值模拟及热成形工艺分析。通过回归分析法建立模型参数关于Z参数的表达式,获得流变应力与变形条件的关系。

 

关键词: BR1500HS超高强度钢;动态回复;Z参数;本构模型

A constitutive model for ultrahigh strength steel BR1500HS and its validation
XIA Yufeng, JI Shuai, ZHANG Yandong

School of Material Science and Engineering, Chongqing University, Chongqing 400044, China

Abstract:The deformation behaviors of ultrahigh strength steel BR1500HS at elevated temperature were studied by performing hot tension tests at temperatures of 1 023, 1 073, 1 123 and 1 173 K and strain rates of 0.01, 0.10 and 1.00 s-1 on a Gleeble3500 thermo-mechanical simulator. The activation energy, hardening exponent and other material constants were determined by the basic theory of creep and experimental curves, and the Zener-Hollomon parameter was also introduced. The effects of work hardening and dynamic recovery on the flow stress were described through the dislocation evolution model, and the constitutive model containing parameters such as saturated stress (σss), yield stress (σ0) and dynamic recovery coefficient (r) was established. The results show that the model curves are highly in accord with the experimental ones, which shows that the constitutive model is accurate enough to be applied for numerical simulation and provide guide for hot forming process. The relationships between the parameters in constitutive model and Zener-Hollomon parameter can be established by regression analysis, and thus the relationship between flow stress and deformation conditions can be achieved.

 

Key words: ultrahigh strength steel BR1500HS; dynamic recovery; parameter Z; constitutive model

中南大学学报(自然科学版)
  ISSN 1672-7207
CN 43-1426/N
ZDXZAC
中南大学学报(英文版)
  ISSN 2095-2899
CN 43-1516/TB
JCSTFT
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