摘要
利用光学显微镜、扫描电子显微镜和X射线衍射仪分析了铸态ADC12-xY（x=0-1.90）合金的组织和相组成,并测试了其流动性能和拉伸力学性能。结果表明,添加Y可显著细化ADC12合金的铸态组织,不仅使初生α-Al由粗大树枝晶转变为细小胞状晶和等轴晶,而且使针状共晶硅转变为细小纤维状或颗粒状,分布更均匀,等轴晶和颗粒状的共晶硅数目大大增加,同时生成针状Al3Y新相。随着Y含量的增加,合金的铸态流动性能和拉伸力学性能均先提高后降低。当Y含量为0.85%时,合金综合性能最佳：流动长度为1541 mm,室温抗拉强度和伸长率分别达到225 MPa和3.5%,较ADC12合金分别提高20%、20%和133%,同时具有优异的高温拉伸力学性能。加入Y后,室温拉伸断口中的解理台阶和河流花样明显减少,解理台阶尺寸亦明显减小,而韧窝明显增多且加深。
Microstructures and phase compositions of as-cast ADC12-x Y（x = 0 - 1. 90） alloys were studied by optical microscope,scanning electron microscopy and X-ray diffraction. Meanwhile,the flow property and tensile mechanical property were tested. The results show that adding the yttrium（Y） can refine as-cast microstructure of ADC12 alloy significantly. Not only the primary α-Al changes from the coarse dendrites to fine cellular and equixed grains,but also the eutectic silicon changes from acicular to fibrous or granular shapes. The eutectic silicon distributes more uniformly. The equixed grains and eutectic silicon particles increase obviously. Meanwhile,the acicular new phase Al3 Y is precipitated. With increasing Y content,the flow and tensile mechanical properties of the alloy are first enhanced,and then reduced.When the Y content is 0. 85%,the overall performance reaches the maximum. The flow length is 1541 mm. The tensile strength and elongation at ambient temperature are 225 MPa and 3. 5%. Compared with the corresponding values of ADC12 alloy,the improving amplitude is 20%,20%and 133%,respectively. Meanwhile,the alloy exhibits excellent tensile mechanical properties at elevated temperature. After adding Y,cleavage steps number and size and river patterns in the tensile fracture decrease obviously at room temperature,while the dimples increase and become deep significantly.
作者
张银帅
黄正华
戚文军
徐春杰
周永欣
李扬德
李卫荣
ZHANG Yin-shuai;HUANG Zheng-hua;QI Wen-jun;XU Chun-jie;ZHOU Yong-xin;LI Yang-de;LI Wei-rong(Guangdong Provincial Key Laboratory for Technology and Application of Metal Materials and Processing,Guangzhou 510650,China;School of Materials Science and Engineering,Xi＇an University of Technology;Dongguan EONTEC Co.,Ltd.,Dongguan 523662,China）Toughening,Guangdong Institute of Xi＇an 710048,China)
出处
《稀土》
EI
CAS
CSCD
北大核心
2018年第5期40-48,共9页
Chinese Rare Earths
基金
广东省产学研合作项目(2014B090903016)
广东省国际科技合作项目(2014A050503002)
粤港共性技术招标项目(2013B010138001)
东莞市产学研合作项目(2015509134108)
广东省科学院科研平台环境与能力建设专项(2016GDASPT-0320)
关键词
ADC12合金
Y变质
组织
流动性能
力学性能
ADC 12 alloy
Y modification
microstructure
flow property
mechanical property
