镧和熔体急冷对过共晶铝硅合金的协同作用研究  

Synergistic Effect of Lanthanum and Melt Quenching on Hypereutectic Al-Si Alloys

作　　者：荆伊蕾 朱泽 刘亚 王建华[1,2] Jing Yilei;Zhu Ze;Liu Ya;Wang Jianhua(Jiangsu Key Laboratory of Material Surface Science and technology,School of Materials Science and Engineering,Changzhou University,Changzhou 213164,China;National Experimental Teaching Demonstration Center of Materials Science and Engineering,Changzhou University,Changzhou 213164,China)

机构地区：[1]常州大学材料科学与工程学院,江苏省材料表面科学与技术重点实验室,江苏常州213164 [2]常州大学材料科学与工程国家级实验教学示范中心,江苏常州213164

出　　处：《稀有金属》2025年第1期20-28,共9页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(52071032)资助。

摘　　要：本文采用熔体急冷装置对未含镧(La)和含0.1%La(质量分数)的过共晶铝硅合金进行熔体急冷处理,采用光学显微镜(OM)和扫描电镜(SEM)分析过共晶铝硅合金凝固组织,利用维氏显微硬度计测试共晶组织显微硬度。结果表明,对Al-(16-24)Si合金进行熔体急冷处理可以抑制合金凝固时初生硅的生长,使共晶组织得到细化,并使共晶组织的显微硬度提高。0.1%La与熔体急冷协同作用可明显抑制合金凝固时初生硅的形核和生长,凝固组织中初生硅面积分数大幅减少;同时进一步细化共晶组织并使共晶硅变为短棒状,共晶组织的显微硬度得到进一步提高。因此,La元素和熔体急冷协同作用是改善过共晶铝硅合金的凝固组织和提高共晶组织硬度的有效方法。Under traditional casting conditions,coarse massive primary silicon phase and lamellar acicular eutectic silicon phase usually exist in the solidification structure of hypereutectic Al-Si alloys with silicon content greater than 13%.Since the hardness of silicon is much higher than that of the matrix aluminium phase,stress concentration is easy to occur around the coarse silicon phase,which becomes the place for early crack initiation and fracture.Refining the silicon phase to improve the solidification structure of the alloy will effectively reduce the stress concentration phenomenon,reduce the possibility of brittle fracture,improve the mechanical properties of the alloy,and realize the lightweight application of hypereutectic Al-Si alloy.In this paper,the synergy effect of lanthanum and melt quench on the solidification microstructure and mechanical properties of hypereutectic Al-Si alloy was studied,and the effect was directly reflected by quantitative analysis of the solidification microstructure.Al-x Si(x=16,18,20,22 and 24) alloys were smelted at 850 ℃,and the effect of melt quench cooling on the solidification microstructure of hypereutectic Al-x Si alloys was studied through a drainage copper tube at-160 ℃ during casting.In order to study the synergistic effect of lanthanum and melt quench,0.1% of La was added after melting the alloy,which was fully stirred and fused.After being held for 30 min,the alloy samples were cast into the metal type with the inner cavity size of Φ12 mm×100 mm by drainage copper tube.The solidification microstructure changes of Al-x Si and Al-x Si-0.1La alloys before and after melt quenching were observed by optical microscope(OM),the solidification microstructure of the alloys was quantitatively analyzed by software Image-Pro Plus 6.0,and the morphology of eutectic silicon in the solidification microstructure of deepetching hypereutectic the alloys was observed by scanning electron microscope(SEM).The microhardness of the alloys was measured by micro-Vickers hardness teste

关 键 词：过共晶铝硅合金 镧(La) 熔体急冷 凝固组织 力学性能 

分 类 号：TG24[金属学及工艺—铸造] TG146.21[一般工业技术—材料科学与工程]