Li/Sc复合添加对铸态Al-Cu-Mg铝合金微观组织和硬度的影响规律  

Effect of Li/Sc Composite Addition on Microstructure and Hardness of As-cast Al-Cu-Mg Alloys

作　　者：范航航 刘飞[1,2] 郑亦玮 白朴存 崔晓明[1] 王海波[3] 靳亮 FAN Hanghang;LIU Fei;ZHENG Yiwei;BAI Pucun;CUI Xiaoming;WANG Haibo;JIN Liang(College of Materials Science and Engineering,Inner Mongolia University of Technology,Hohhot 010051,China;Bin Zhou Bohai Piston Co.,Ltd.,Binzhou 256602,Shangdong,China;Inner Mongolia Synthetic Chemical Engineering Institute,Hohhot 010010,China)

机构地区：[1]内蒙古工业大学材料科学与工程学院,呼和浩特010051 [2]滨州渤海活塞有限公司,山东滨州256602 [3]内蒙合成化工研究所,呼和浩特010010

出　　处：《材料导报》2024年第24期224-230,共7页Materials Reports

基　　金：内蒙古自治区自然科学基金(2022FX06,2023LHMS05015);内蒙古自治区直属高校基本科研业务费项目(JY20220184,ZTY2023047);内蒙古工业大学科学研究项目(BS2021043);中央引导地方科技发展资金项目(2023ZY0012)。

摘　　要：Al-Cu-Mg合金具有优异的比强度、加工性能和耐腐蚀性能,被广泛应用于航空航天等领域。然而,该合金在250℃以上的环境中服役时,纳米级沉淀相迅速粗化,强化效果显著下降,致使合金性能严重恶化。本工作以Li/Sc复合添加的Al-Cu-Mg合金为研究对象,利用OM、XRD、SEM、TEM、维氏硬度计等测试手段对合金铸态显微组织、硬度和第二相进行了分析。结果表明:复合添加Li/Sc后,Al-Cu-Mg合金由粗大的树枝晶组织转变为等轴晶组织,α-Al的平均晶粒尺寸从83.58μm降低至29.75μm,细化效果达64.41%。硬度从HV88.73提升到HV116.70,提高了31.52%,合金强化机理为细晶强化和第二相强化。合金中存在成分偏析,部分Cu元素在晶界上富集,形成网状分布的Al_(2)CuMg相和块状Al_(2)Cu相,而在晶粒内部存在块状的Al_(6)CuLi_(3)准晶相、Al^(3)Sc相和AlCuSc相,以及链状分布的Al_(2)CuMg相。其中,AlCuSc相作为合金中的有害相,在形核时会消耗一部分Sc、Cu元素,致使其他强化相的体积分数减少,降低强化效果,应减少该相的形成。Al-Cu-Mg alloys have many advantages,such as excellent specific strength,processing performance and corrosion resistance,which are widely used in aerospace and other fields.However,when the alloys are in service in an environment above 250℃,the nanoscale precipitated phases should be coarsen rapidly,and the strengthening effect decreases significantly,which results in a serious deterioration of the alloys’performance.In this work,took the Al-Cu-Mg alloys with Li/Sc composite addition as research materials,analyzed the as-cast microstructure,hardness and second phase of the alloys by OM,XRD,SEM,TEM and Vickers hardness tester.The results showed that with Li/Sc addition,the Al-Cu-Mg alloys changed from coarse dendrite structure to equiaxed crystal structure,the average grain size ofα-Al decreases from 83.58μm to 29.75μm,and the refinement effect reached 64.41%.The hardness was increased from HV88.73 to HV116.70,an increase of 31.52%.The strengthening mechanism of the alloys was fine grain strengthening and second phase strengthening.There was composition segregation in the alloys.some Cu elements are enriched on the grain boundary,forming a network distribution of Al_(2)CuMg phase and bulk Al_(2)Cu phase,while in the grain there were bulk Al_(6)CuLi_(3)quasicrystal phase,Al_(3)Sc phase and AlCuSc phase,and chain distribution of Al_(2)CuMg phase.Among them,AlCuSc phase,as a harmful phase in the alloy,consumed a part of Sc and Cu elements during nucleation,which would result in a decrease in the volume fraction of other strengthening phases to decrease the strengthening effect.The formation of this phase should be reduced.

关 键 词：AL-CU-MG合金 微组织 微合金化 细晶强化 第二相强化 

分 类 号：TG146.2[一般工业技术—材料科学与工程]