ZL205A铝合金淬火过程本构模型及数值模拟  

Constitutive model and numerical simulation of ZL205A aluminum alloy during quenching

作　　者：邓肖峰 王凯 石伟[1] DENG Xiao-feng;WANG Kai;SHI Wei(Department of Mechanical Engineering,Tsinghua University,Beijing 100084,China)

机构地区：[1]清华大学机械工程系,北京100084

出　　处：《材料热处理学报》2021年第8期125-136,共12页Transactions of Materials and Heat Treatment

基　　金：国家国际科技合作专项项目(2014DFG72020)。

摘　　要：通过等温压缩实验研究了ZL205A铝合金在宽温度范围(2~500℃)和宽应变速率范围(0.001~0.1 s^(-1))条件下的塑性变形行为。采用Arrhenius模型、Extended Ludwik-Hollomon(ELH)模型和BP人工神经网络模型描述ZL205A铝合金的流动应力,并应用在ZL205A工件淬火过程有限元仿真中。结果表明:ZL205A铝合金在低温段和高温段有着不同的变形机制,低温段以应变强化为主,在一定温度和应变速率情况下,会出现负应变速率敏感性。在高温段流动应力对应变速率较敏感,体现为正应变速率敏感性。BP神经网络模型相较于其他两个模型,其拟合精度和预测精度都更好,平均拟合相对误差为0.9594%,平均预测相对误差约10%。阶梯件的有限元仿真结果表明采用不同本构模型对阶梯件的应力场的分布影响不大,但是会影响应力场的大小。The plastic deformation behavior of ZL205A aluminum alloy in wide temperature range(25-500℃)and strain rate range(0.001-0.1 s^(-1))was studied by isothermal compression experiments.Arrhenius model,Extended Ludwik-Hollomon(ELH)model and BP neural network model were used to describe the flow stress of the ZL205A aluminum alloy and were used in the finite element simulation of a ZL205A part during quenching.The results show that the ZL205A aluminum alloy has different deformation mechanisms in the low temperature stage and high temperature stage.The flow stress in low temperature stage is dominated by strain hardening,and the negative strain rate sensitivity(SRS)appears at a certain range of temperatures and strain rates.In the high temperature stage,the flow stress is more sensitive to the strain rate with a feature of the positive strain rate sensitivity.Compared with the Arrhenius model and the ELH model,the BP neural network model has better fitting accuracy and predictive accuracy,with an average fitting relative error of 0.9594% and an average prediction relative error of about 10%.The finite element simulation results of the ZL205A part during quenching show that the use of different constitutive models has little effect on pattern of the distribution of residual stresses in the quenched work-piece,but affects the maximum and minimum values of residual stresses.

关 键 词：ZL205A合金 应变速率敏感性 本构模型 人工神经网络 

分 类 号：TG146.2[一般工业技术—材料科学与工程]