Al-Si-Ti(B)-P体系相关系及铝硅合金正-反向变质机理研究

Because of its many advantages, Al-Si alloy is widely used in industry. The researches are mainly focused on the modification of primary and eutectic silicon. Little attention has been paid to the effect of mocification on supercooling degree and non-equilibrium eutectic point. We found that relative percentage of primary silicon and eutectic structure in Al-Si alloy could be changed through reverse modification. But the reverse modification mechanisms and the changing law of microstructure and comprehensive mechanical properties of the modified Al-Si alloy are not clear. The phase relationships of Al-Ti(B)-P, Al-Si-Ti(B) and Al-Ti(B)-Si-P systems need to be clarified. In this project, phase relationships on Al-Ti(B)-P、Al-Si-Ti(B) and Al-Ti-Si(B)-P systems would be experimentally determined by using alloy balance method. Useing collected thermodynamic data of these relevant systems, the thermodynamic evaluation and optimization of these phase diagrams would be carried out. These researches could be used to interpretate the reverse and positive-reverse modification mechanisms and accurately analyse the solidification microstructure of the studied Al-Si alloy. The reverse and positive-reverse modification mechanisms, the effect of modification on supercooling degree and non-equilibrium eutectic point as well as on microstructure and the comprehensive mechanical properties of Al-Si alloy would be investigated systematicly. The mathematical model would be established to forecast and analyse the microstructure and mechanical properties of Al-Si alloy. The researches can provide theoretical guide for the production of high quality Al-Si alloy.

铝硅合金因具有许多优点在工业中得到广泛应用，对其研究集中在初晶硅和共晶硅的变质处理，很少关注变质处理对铝硅合金凝固过冷度和非平衡共晶点的影响。申请者发现反向变质可改变铝硅合金中初晶硅和共晶组织的相对百分数，但反向变质机理、合金显微组织和综合力学性能变化规律尚不清楚，与此相关的Al-Ti(B)-P、Al-Si-Ti(B)和Al-Ti(B)-Si-P体系相关系亟待澄清。本项目采用合金平衡法测定Al-Ti(B)-P、Al-Si-Ti(B)和Al-Ti-Si(B)-P体系相关系，搜集其热力学数据进行相图热力学评估与优化，为诠释铝硅合金的反向和正-反向复合变质机理及准确分析铝硅合金凝固组织提供依据。系统研究反向和正-反向复合变质变质机理及变质处理对铝硅合金凝固过冷度和非平衡共晶点、显微组织和综合力学性能的影响，建立数学模型对铝硅合金显微组织和综合力学性能进行预测，为生产高质量的铝硅合金提供理论指导。

亚共晶、共晶和过共晶铝硅合金具有许多优点，在工业领域中得到广泛应用，充分挖掘其力学性能的潜力具有重要科学意义，因此对这类材料进行研究具有很大的应用价值。. 本项目研究重点关注正向和反向变质以及正-反向复合变质处理对各种铝硅合金的非平衡共晶点移动的影响，同时研究变质处理对铝硅合金中初生α-Al相、初生硅相和共晶组织体积分数及合金综合力学性能的影响。. 本项目测定了Al-B-P和Al-Si-B三元系700℃等温截面相平衡关系及Al-Si-Ti三元系550℃ 等温截面相平衡关系，为正确分析变质处理铝硅合金显微组织及反向变质和正-反向复合变质机理提供了理论依据。采用热处理方法改善共晶和过共晶铝硅合金中硅相的形态，并对其球化机理进行了分析。采用Al-5Ti-B(Al-3B)和Al-3P变质剂对分别对亚共晶、共晶和过共晶铝硅合金进行了正向和反向单变质以及正-反向复合变质处理。本项目研究变质处理对铝硅合金非平衡共晶点位置的影响，定量分析变质处理前后各种铝硅合金中初晶α-Al相、初晶硅相和共晶组织的相对体积百分数及其变化对铝硅合金综合力学性能的影响，建立变质处理共晶铝硅力学性能的预测模型，系统阐明亚共晶、共晶和过共晶铝硅合金的正向、反向和正-反向复合变质机理。. 在项目研究期内，在国内外重要期刊上发表已标注本基金项目资助的论文15篇（其中SCI/EI收录论文13篇），另有接收论文2篇；申报8件国家发明专利，其中获专利授权3件。培养硕士研究生6人，其中5人已顺利毕业。