Cu、Mg对亚共晶Al-Si合金组织的性能影响毕业论文.doc

Cu、Mg对亚共晶Al-Si合金组织的性能影响 PAGE 10 Cu、Mg对亚共晶Al-Si合金组织性能影响 摘要 本实验主要通过正交试验表，考查了不同的Cu、Mg的含量对亚共晶Al-Si合金组织在室温和高温（250℃）条件下的力学性能影响规律，利用光学金相显微镜（OM）、扫描电镜（SEM）对合金中富Cu相、富Mg相的组织组成进行了分析。 实验结果表明：Cu、Mg是提高Al-7wt%Si亚共晶铝硅合金室温及高温强度的主要因素；在三个元素中，Cu对抗拉强度影响最大，而Mg对抗拉强度影响最小；Cu对伸长率影响最小，Mg对伸长率影响最大，且呈负面影响；随着Mg含量的增加，合金室温及250℃抗拉强度升高而伸长率下降，随着Cu含量的增加，合金室温抗拉强度升高而伸长率下降，250℃抗拉强度升高而伸长率呈先升后降趋势；根据正交试验得出的数据加以验证，分析其金相显微组织形貌及扫描断口，最后确定亚共晶Al-Si合金的最优成分为Si：7%、Cu：2.5%、Mg：0.3%；Al-7Si-2.5Cu-0.3Mg合金经过500℃×3h+520℃×10h固溶处理+60℃水淬热处理后力学性能为室温：σb≥325Mpa，δ5≥6.0％；250℃：σb≥220Mpa，δ5≥9.2％。 关键词：亚共晶铝硅合金；固溶处理；显微组织；力学性能 Cu、Mg on the Microstructure and Properties of?Hypoeutectic Al-Si Alloy Effect Abstract This experiment mainly through orthogonal test table,to examine the content of the different Cu,Mg of Hypoeutectic Al-Si alloy at room temperature and high temperature (250 ℃) mechanical properties influence of temperature conditions, By using optical microscope (OM), scanning electron microscopy (SEM) of Cu rich phases, Mg rich phase of tissue composition analysis. The experimental results show that:Cu, Mg is the main reason for the increase of Al-7wt%Si hypoeutectic aluminum silicon alloy at room temperature and high temperature strength; In the three element, Cu has the greatest effect on tensile strength, Mg tensile strength with minimal impact; Minimal impact on the elongation of Cu, Mg biggest influence on elongation,and there was a negative impact; With the increase of Mg content,alloy at room temperature and 250 ℃ higher tensile strength and elongation decreased, with the increase of Cu content, the tensile strength increases and elongation, tensile strength and elongation at break increased 250 ℃ increased first and then decreased; Verify?according to?the orthogonal experiment?data,?finally?determining the optimal?composition?of Al-Si hypoeutectic alloy?is Si:7%,?Cu:2.5%,?Mg:0.3%；Al-7Si-2.5Cu-0.3Mg?alloy?after 500?℃?3h+520℃ ×?10h solid solution treatment temperature of +60 ℃?water quenching heat treatment for mechanica