Al-Cu-Mg-Ag合金峰时效前微观组织演变及屈服强度数值模拟

Simulation of Microstructure Evolution and Yield Strength of Al-Cu-Mg-Ag Alloys before Peak Aging Stage

摘要:

求解了高Cu/Mg比的Al-Cu-Mg-Ag合金峰值时效前微观结构演变及时效强化的预测模型。首先，建立影响Mg与Mg-Ag原子簇对W相析出过程中消耗Cu原子定量关系的关键参数表达式，即W析出相与基体的界面能模型。在假设合金为伪二元的前提下，基于热动力学模型和经典的形核、长大理论，建立了Al-Cu-Mg-Ag合金中Cu溶质原子在两种强化相中的定量分配模型，它可以预测两种强化粒子的半径和析出密度、溶质浓度随温度和时间的演变。最后求解了基于Orowan方程的强化模型。模型预测与实验结果吻合较好，证明了模型的可靠性

Abstract:

A prediction model for microstructure evolution and ageing strengthening was developed for Al-Cu-Mg-Ag alloys with high Cu/Mg ratio before peak ageing stage. Firstly, the expression of critical parameters was built for the quantitative relationship of Mg and Mg-Ag atom clusters to consumed Cu atoms during Ω phase precipitation, i.e. the interface energy model of Ω precipitates and the substrate. Provided the alloy is pseudo-binary approximation, quantitative distribution model of Cu solute atom in the two strengthened phases for the Al-Cu-Mg-Ag alloy was set up based on the thermodynamic model and the classical nucleation and growth theories. The model can predict the evolution of the radius and precipitation density of two strengthened particles and the solute concentration with temperature and time. Finally, the strengthening model based on Orowan equation was solved. The microstructure evolution and strength prediction of the model were generally in good agreement with the experimental data, which verified the reliability of the models.