Al-7Si-Mg铸造铝合金凝固和热处理过程微观组织模拟和屈服强度预测

发布时间：2018-11-15 10:40

【摘要】：Al-7Si-Mg铸造铝合金的力学性能受凝固条件和热处理工艺参数的影响,如何建立各阶段工艺参数与微观组织、合金性能之间的定量化模型,对于优化工艺条件,提高合金性能具有重要的工程应用价值。建立了能够描述凝固、固溶处理和时效处理过程中微观组织演变的全过程、多尺度数值模型,并建立了相应强化模型,实现铸件最终屈服强度的预测。模拟了Al-7Si-Mg合金在各阶段的微观组织演变,并与实验结果进行了比较,分析了工艺参数对微观组织和合金屈服强度的影响规律。模拟和实验结果表明:二次枝晶臂间距随着冷却速率的增大而减小。Mg2Si颗粒的溶解和共晶Si的熔断在短时的固溶处理就可以完成。提高时效温度会促进时效析出,但会降低时效峰值强度,而增加Mg含量能够提高合金的屈服强度。最后分析了本模型存在的问题,指明该模型今后发展、充实与完善之处。
[Abstract]:The mechanical properties of Al-7Si-Mg cast aluminum alloy are affected by solidification conditions and heat treatment process parameters. Improving the properties of the alloy has important engineering application value. A multi-scale numerical model was established to describe the evolution of microstructure during solidification, solution treatment and aging treatment, and the corresponding strengthening model was established to predict the ultimate yield strength of castings. The microstructure evolution of Al-7Si-Mg alloy in various stages was simulated and compared with the experimental results. The effect of process parameters on the microstructure and yield strength of the alloy was analyzed. The simulation and experimental results show that the secondary dendritic arm spacing decreases with the increase of cooling rate, and the dissolution of Mg2Si particles and the melting of eutectic Si can be completed in a short time. Increasing the aging temperature can promote the precipitation of aging, but decrease the peak strength of aging, and increase the content of Mg can increase the yield strength of the alloy. Finally, the problems existing in this model are analyzed, and the future development, enrichment and perfection of the model are pointed out.
【作者单位】：清华大学材料学院先进成形制造教育部重点实验室;明志科技有限公司;
【基金】：国家重点基础研究发展计划项目(2011CB706801) 国家自然科学基金项目(51374137和51171089) 国家科技重大专项项目(2012ZX04012-011和2011ZX04014-052)资助
【分类号】：TG166.3;TG292

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