挤压态Al-Mg-Si合金强化相析出动力学及其模型修正

Strengthening phase precipitation kinetics and model modification for extruded Al-Mg-Si alloy

基于建立的Al-Mg-Si合金时效析出强化模型,针对针/棒状析出相与盘/片状析出相的不同特点,对针/棒状析出相强化模型的边界条件进行了修正;同时,对出现峰值时效平台时屈服强度的计算公式进行了修正,综合评估了合金屈服强度与时效工艺的关系。通过透射电子显微镜观察得到的析出相参数计算合金的理论屈服强度,并与拉伸实验得到的力学性能进行比较。结果表明,修正后的模型计算结果与实验结果吻合更好,说明修正后的模型能够更准确地预测Al-Mg-Si合金时效过程中,出现峰值时效平台时的微观组织演变与宏观力学性能之间的定量关系,扩展了模型的应用范围,有助于合金塑性变形趋势的预测。

Based on the established aging precipitation strengthening model of Al-Mg-Si alloy,the boundary conditions of the needle/rodlike precipitation strengthening model were modified aiming at the different characteristics of the needle/rod-like and plate/disc-like precipitations.At the same time,the calculation fomula of yield strength was modified considering the peak-aging platform,and the relationship between yield strength and aging process was comprehensively evaluated.The theoretical yield strength was calculated by precipitation parameters obtained from Transmission Electron Microscopy(TEM),which was compared with the mechanical properties obtained from the tensile experiments.The results show that the calculated results of modified model have a better agreement with the experimental results,which indicates that the modified model can predict the quantitative relationship between the microstructure evolution and the macroscopic mechanical properties during the aging process of Al-Mg-Si alloy considering the peak-aging platform more accurately.Thus,the application scope of the model is expanded,which is helpful to predict the plastic deformation of alloy.