Al_(2.5)Cu_(0.5)Ti中间合金对Al-7Si合金微观组织和力学性能的影响  

Influences of Al_(2.5)Cu_(0.5)Ti master alloy on microstructure and mechanical properties of Al-7Si alloy

作　　者：王平波[1,2] 孙赫阳 张岩 张杰 李庆林[1] WANG Pingbo;SUN Heyang;ZHANG Yan;ZHANG Jie;LI Qinglin(State Key Laboratory of Advanced Processing and Recycling ofNon-ferrous Metals,Lanzhou University of Technology,Lanzhou730050,China;State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi’an 710072,China;Wuxi Huarun Shanghua Technology Co.,Ltd.,Wuxi 214028,Jiangsu,China)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,兰州730050 [2]西北工业大学凝固技术国家重点实验室,西安710072 [3]无锡华润上华科技有限公司,江苏无锡214028

出　　处：《材料工程》2023年第12期84-92,共9页Journal of Materials Engineering

基　　金：国家自然科学基金项目(51561021);甘肃省重点研发计划项目(21YF5GA075);甘肃省自然科学基金重点项目(23JRRA752)。

摘　　要：通过真空电弧熔炼炉制备Al_(2.5)Cu_(0.5)Ti中间合金,利用光学显微镜(OM)、扫描电子显微镜(SEM)、电子探针显微分析仪(EPMA)、X射线衍射仪(XRD)、差热分析仪(DSC)和万能材料试验机,研究不同添加量(0.3%,0.5%,0.7%,0.9%和1.3%,质量分数,下同)Al_(2.5)Cu_(0.5)Ti中间合金对Al-7Si合金微观组织和性能的影响。结果表明:随着Al_(2.5)Cu_(0.5)Ti合金添加量的增加,Al-7Si合金中初生α-Al和共晶Si组织被显著细化。与未添加Al_(2.5)Cu_(0.5)Ti中间合金相比,当Al-7Si合金中添加0.9%Al_(2.5)Cu_(0.5)Ti中间合金后,初生α-Al晶粒尺寸从218μm减小到80μm,二次枝晶间距从25μm减小到9.3μm;共晶Si组织由粗大的针片状细化为短片状和短棒状,平均长度和宽度分别从34.8μm和4μm减小到11.6μm和1.7μm;合金的抗拉强度和伸长率分别达到184 MPa和9.3%,与未变质合金的力学性能(162 MPa和3%)相比分别提高了13.6%和210%,断裂模式由韧脆混合断裂模式转变为韧性断裂。然而,当Al_(2.5)Cu_(0.5)Ti合金的添加量增加到1.3%时,发生过变质现象,导致Al-7Si合金组织粗化,力学性能下降。The influences of adding Al_(2.5)Cu_(0.5)Ti master alloy(0.3%,0.5%,0.7%,0.9%and 1.3%,mass fraction,the same below)prepared by vacuum arc melting furnace with a water-cooled copper mold on the microstructure and mechanical properties of Al-7Si alloy were investigated by optical microscopy(OM),scanning electron microscopy(SEM),electron probe micro-analysis(EPMA),X-ray diffractometer(XRD),differential scanning calorimeter(DSC)and tensile testing machine.The results show that the primaryα-Al and eutectic Si structure of Al-7Si alloy with Al_(2.5)Cu_(0.5)Ti master alloy addition are significantly refined.Compared with the unadded Al_(2.5)Cu_(0.5)Ti master alloy,when the addition concentration of Al_(2.5)Cu_(0.5)Ti master alloy is up to 0.9%,the primaryα-Al is refined from coarse dendrites to fine equiaxed dendrites and the size reduces from 218μm to 80μm,the second dendrite arm spacing(SDAS)significantly decreases from 25μm to 9.3μm.The morphology of eutectic Si is transformed from coarse needle/flake to short flake and rod.The length of eutectic Si structure reduces from 34.8μm to 11.6μm,and the width decreases from 4μm to 1.7μm.The tensile test indicates that when the addition content of Al_(2.5)Cu_(0.5)Ti master alloy is up to 0.9%,the ultimate tensile strength(UTS)is increased by 13.6%from 162 MPa to 184 MPa,and the elongation(El)is enhanced by 210%from 3%to 9.3%.The fracture mode of the alloy changes from ductile-brittle mixed fracture to ductile fracture mode.However,when the addition content of Al_(2.5)Cu_(0.5)Ti alloy increases to 1.3%,excessive modification occurs,resulting in coarsening of the microstructure and decrease in mechanical properties.

关 键 词：Al-7Si合金 Al_(2.5)Cu_(0.5)Ti中间合金 初生Α-AL 共晶Si 力学性能 

分 类 号：TG146.21[一般工业技术—材料科学与工程]