Die-cast Al–Si aluminium alloys are increasingly used in the lightweight design of automobiles; their mechanical properties under dynamic loading are crucial and thus must be investigated. The original Johnson–Cook (J–C) constitutive model does not accurately predict the mechanical properties of this alloy, which further affects the reliability of subsequent analysis and calculations. To improve the predictive accuracy of the constitutive model and investigate the dynamic mechanical properties of this alloy, high-speed tensile tests of die-casting aluminium alloy Al–10Si–yCu–xMn–zFe are conducted. The tests are executed at room temperature using a universal electrical testing machine and a high-velocity testing system in a wide strain rate range of 1–800 s⁻¹. The tensile deformation behaviour of this alloy at various strain rates is investigated. The experiments show that the flow stress of the alloy gradually increases with strain and varies significantly with the strain rate. The J–C model is unsuitable for predicting the flow stress of this alloy owing to its unsatisfactory goodness-of-fit. To accurately predict the flow stress of die-cast Al–Si aluminium alloys, we propose a new model based on experiments. Unlike other models, the proposed model incorporates the critical strain and flow stress limit value, which allows the flow stress to be predicted more precisely at various strain rates over a wide strain range of 0–0.17. The experimental data of other die-cast Al–Si alloys validate our model. The goodness-of-fit of the proposed model for this alloy is higher than that of the J–C model, which demonstrates that our model outperforms existing models in terms of estimation accuracy.

压铸铝硅铝合金越来越多地用于汽车的轻量化设计；它们在动态载荷下的机械性能至关重要，因此必须进行研究。原始的Johnson-Cook(J-C)本构模型并不能准确预测该合金的力学性能，进一步影响了后续分析计算的可靠性。为了提高本构模型的预测精度并研究该合金的动态力学性能，对压铸铝合金 Al–10Si– y Cu– x Mn– z Fe进行了高速拉伸试验。这些测试是在室温下使用通用电气测试机和高速测试系统在 1–800 秒的宽应变率范围内执行的⁻¹. 研究了该合金在不同应变率下的拉伸变形行为。实验表明，合金的流变应力随应变逐渐增大，且随应变速率变化显着。由于拟合优度不理想，J-C 模型不适用于预测该合金的流变应力。为了准确预测压铸 Al-Si 铝合金的流变应力，我们提出了一种基于实验的新模型。与其他模型不同，所提出的模型结合了临界应变和流动应力极限值，这使得可以在 0-0.17 的宽应变范围内以各种应变率更精确地预测流动应力。其他压铸铝硅合金的实验数据验证了我们的模型。该合金的拟议模型的拟合优度高于 J-C 模型，