(揚州大學 機械工程學院，揚州 225127)
摘 要: 合理的本構(gòu)模型是實現(xiàn)精確模擬鎂合金擠壓過程的關鍵，基于均勻化態(tài)AZ80鎂合金在應變速率0.001~1 s-1、變形溫度523~673 K下的熱壓縮實驗數(shù)據(jù)，建立了改進的Z-A模型來描述AZ80鎂合金的熱變形行為，并在此基礎上，通過考慮應變對材料參數(shù)的影響，提出優(yōu)化的Z-A模型。對兩種模型預測精度進行定量分析表明：優(yōu)化的Z-A模型對流動應力的預測效果較好，相關系數(shù)R和平均絕對相對誤差EAR的計算值分別為0.9962和3.60%；改進的Z-A模型的預測結(jié)果相對較差，其R值和EAR值分別為0.94和8%。比較分析表明，優(yōu)化的Z-A模型具有良好的適應性，可以在整個應變范圍內(nèi)(0~0.9)很好地預測不同變形條件下的流動應力，因而工程適用范圍廣；改進的Z-A模型不能描述加工硬化-動態(tài)回復階段的流動應力，因而預測精度較低。
關鍵字: AZ80鎂合金；流動應力；本構(gòu)模型；Zerilli-Armstrong模型
（School of Mechanical Engineering, Yangzhou University, Yangzhou 225009, China）
Abstract:The reasonable constitutive model is the key to realize the accurate simulation of magnesium alloy extrusion process, based on the thermal compression test of homogenized AZ80 magnesium alloy at the strain rate of 0.001 to 1 s-1 and deformation temperature of 523 to 673 K, a modified Zerilli-Armstrong (Z-A) model was established to describe the thermal deformation behavior of the alloy, and on this basis, by considering the effect of strain on material parameters, an optimized model was proposed. The quantitative analysis of the prediction accuracy of the two models shows that the optimized Z-A model has a better prediction effect on the flow stress, and the calculated values of correlation coefficient R and average absolute relative error EAR are 0.9962 and 3.60%, respectively. The prediction result of the modified Z-A model is relatively poor, and its R value and EAR value are 0.94 and 8%, respectively. The comparative analysis shows that the optimized Z-A model has good adaptability and can well predict the flow stress under different deformation conditions in the whole strain range (0-0.9), so its engineering application range is wide. The modified Z-A model cannot describe the flow stress in the stage of work hardening and dynamic recovery, so its prediction accuracy is low.
Key words: AZ80 magnesium alloy; flow stress; constitutive model; Zerilli-Armstrong model
