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建立了时效析出动力学模型、强化模型以及应变硬化模型,针对Al-7Si-Mg合金开展拉伸性能模拟研究。时效析出动力学模型可以模拟析出相密度、尺寸、分布、体积分数、基体中元素含量等微观组织参数,并结合强化模型获得合金的屈服强度。通过应变硬化模型可模拟合金在拉伸过程的应力-应变曲线,并结合关系式(σ_(UTS)-σ_Y)=m·σ_Y+n+f(T_(ss))获得合金的抗拉强度和延伸率。本工作首先模拟了Al-7Si-0.4Mg合金的析出相特征参数及屈服强度并进行实验验证,分析了模拟结果与实验结果之间存在偏差的可能原因。采用应变硬化模型模拟了Al-7Si-0.36Mg合金在拉伸过程的应力-应变曲线,分析时效处理和铸态组织细化程度对位错存储速率、动态回复速率及合金的应力-应变曲线的影响规律。采用本模型预测了Al-7Si-0.4Mg合金在不同时效温度下的抗拉强度和延伸率,并与实验结果进行对比,分析了二次枝晶臂间距对拉伸性能的影响。最后,对模型存在的局限性及影响拉伸性能预测精度的因素进行了分析。
The aging precipitation kinetics model, strengthening model and strain hardening model were established. Tensile properties of Al-7Si-Mg alloy were simulated. The aging precipitation kinetic model can simulate the microstructure parameters such as density, size, distribution, volume fraction and element content in the matrix, and combine the strengthening model to obtain the yield strength of the alloy. Through the strain hardening model, the stress-strain curve of the alloy during the drawing can be simulated and the tensile strength of the alloy can be obtained by combining the relationship of (σ UTS -σY) = m · σY + n + f (T ss) Elongation. In this work, the characteristic parameters and yield strength of the precipitated phase of Al-7Si-0.4Mg alloy were simulated firstly and verified by experiments. The possible causes of the deviation between simulation results and experimental results were analyzed. The strain-hardening model was used to simulate the stress-strain curve of Al-7Si-0.36Mg alloy during the drawing process. The effects of aging treatment and degree of microstructure refinement on the dislocation storage rate, dynamic recovery rate and stress-strain curve of the alloy Affect the law. Using this model, the tensile strength and elongation of Al-7Si-0.4Mg alloy at different aging temperatures were predicted. Compared with the experimental results, the effect of the secondary dendrite arm spacing on the tensile properties was analyzed. Finally, the limitations of the model and the factors affecting the prediction accuracy of tensile properties are analyzed.