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  • ISSN：0577-6686
机械工程学报

机械工程学报 ›› 2015, Vol. 51 ›› Issue (2): 43-48.doi: 10.3901/JME.2015.02.043

• 材料科学与工程 • 上一篇    下一篇

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基于材料流动轨迹的搅拌摩擦焊接晶粒及焊接区大小预测模型

张 昭1, 2吴 奇1, 2   

  1. 1.大连理工大学工程力学系
    2.大连理工大学工业装备结构分析国家重点实验室
  • 出版日期:2015-01-20 发布日期:2015-01-20
  • 基金资助:
    国家自然科学基金(11172057)、中央高校基本科研业务费专项资金和教育部新世纪优秀人才支持计划(NCET-12-0075)资助项目

Computational Model for Predictions on Welding Zones and Grain Sizes Based on the Flow Trace in Friction Stir Welding

ZHANG Zhao1, 2WU Qi1, 2   

  1. Department of Engineering Mechanics, Dalian University of Technology, Dalian 116024;State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024
  • Online:2015-01-20 Published:2015-01-20

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摘要： 通过热力耦合模型模拟搅拌摩擦焊接过程中的材料行为，并基于材料的运动轨迹区分焊接区域中的搅拌区和热力影响区。给出热力影响区和搅拌区边界处流动轨迹上的真实应变率和温度历史曲线，进一步计算Zener-Holloman参数和搅拌区内的晶粒大小，通过与已有文献的对比验证计算结果的准确性。结果显示尽管应变率分布不均匀，均匀分布的温度使lgZ在搅拌区内均匀分布，这说明温度对搅拌区内晶粒大小变化的影响较应变率更为明显。绕针运动的物质点的应变率明显高于其他运动轨迹上的物质点的应变率，可以达到22 s–1。通过对不同材料流动行为的跟踪可以确定搅拌区和热力影响区的边界。搅拌区晶粒随搅拌头轴肩的增大而增大，且搅拌区尺寸随搅拌头轴肩的增大而增大。较小的搅拌头会使搅拌区的区域变小。

关键词: 搅拌摩擦焊接, 晶粒尺寸, 流动轨迹, 完全热力耦合模型

Abstract: Coupled thermo-mechanical model is used to simulate the material flow in friction stir welding(FSW) The flow traces are studied for the determination of the stirring zone(SZ) and the thermo-mechanical affected zone(TMAZ). The histories of the true strain rate and the temperature on the boundaries of the SZ and the TMAZ are given to calculate the Zener-Holloman parameter and the grain sizes. The comparison to the data in published literature shows the validity of the current model. Results indicate that uniform temperature can lead to uniform lgZ in the SZ, although the distribution of the strain rate is not uniform. This means that the effect of temperature on the grain sizes is much more important than the effect of the strain rate. The strain rates of the material particles in rotation with pin can reach 22 s–1. The boundaries of the SZ and TMAZ can be determined by the different material flow rules of different traced particles. The SZ and the grain sizes are both increased with the increase of the shoulder diameter. Smaller shoulder can lead to smaller SZ.

Key words: coupled thermo-meohanical model, flow trace, friciton stir welding, grain size

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