6013鋁合金平面熱壓縮流變應力曲線修正與本構(gòu)方程Modification of flow stress curves and constitutive equations during hot plane compression deformation of 6013 aluminum alloy

采用Gleeble-3500熱模擬機研究6013鋁合金在613~773 K、0.001~10 s^-1下的平面應變流變力學行為。基于熱傳導對材料變形熱效應的影響，優(yōu)化材料變形溫升的計算方程，分析變形能及熱傳導對實測流變應力誤差的影響。結(jié)果表明：熱傳導對變形溫升的影響不可忽略，其影響隨著真應變的增加和應變速率的降低而更加顯著；通過熱傳導對變形溫升的修正，變形溫升隨變形能的增大呈非線性變化趨勢；在較高應變速率和較低變形溫度下，變形能及熱傳導對材料變形溫升及穩(wěn)態(tài)流變應力的影響明顯；可用包含Zener-Hollomon參數(shù)(Z)的本構(gòu)方程預測6013鋁合金在不同變形條件下的流變應力峰值，其熱變形激活能為364.48 kJ/mol；修正的實測峰值應力與預測值的吻合程度有所提高，平均相對誤差為5.54%。

The hot plane compression deformation behavior of 6013 aluminum alloy was investigated on Gleeble-3500 thermal-mechanical simulating tester in the temperature range from 613 to 773 K and strain rate range from 0.001 to 10 s^-1. The mathematical expression of temperature rising is optimized based on the influence of the heat conduction during hot deformation. Meanwhile, the effects caused by deformation energy and heat conduction on the measured stress errors were analyzed. The results show that the influence of heat conduction cannot be neglected and becomes more obvious with increasing true strain and decreasing strain rate. The relationship between the change of temperature rising corrected by heat conduction and deformation heating is nonlinear. The temperature rising and the steady flow stress are seriously affected by deformation energy and heat conduction during higher stain rate and lower temperature. The peak flow stress can be represented by the Zener-Hollomon parameter (Z) in the hyperbolic sine equation with the hot deformation activation energy of 364.48 kJ/mol. The corrected measured value exhibits a better agreement with the flow stress predicted by the constitutive equation, and the average relative error is 5.54%.

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