Y/Al-5Ti-1B复合变质对Al-7Si合金微观组织和力学性能的影响  

Effect of a Y/Al-5Ti-1B Composite Modifier on the Microstructure and Mechanical Properties of Al-7Si Alloy

作　　者：张杰[1] 张子琦 胡鹏涛 刘玉康 李庆林[1] ZHANG Jie;ZHANG Ziqi;HU Pengtao;LIU Yukang;LI Qinglin(School of Materials Science and Engineering,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学材料科学与工程学院,甘肃兰州730050

出　　处：《铸造技术》2024年第5期446-451,共6页Foundry Technology

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

摘　　要：在传统铸造Al-Si合金中存在的粗大树枝晶α-Al相以及针状共晶Si严重割裂基体,显著降低合金的力学性能。为细化Al-Si合金的组织,提升其力学性能,本文使用扫描电镜(SEM)、电子探针(EPMA)、X射线衍射仪(XRD)以及万能材料试验机,研究了不同添加量Y/Al-5Ti-1B变质剂(Al-5Ti-1B均为2%,稀土Y分别为0.05%、0.1%、0.2%、0.3%、0.4%、0.5%,质量分数)对Al-7Si合金微观组织和力学性能的影响,并探究了其对Al-7Si合金的变质机理。实验结果表明,当Al-5Ti-1B含量为2%、稀土Y含量为0.4%时,变质效果最佳,共晶Si由粗大针状变为细小颗粒状,长和宽分别减小至2.7和0.8μm,相较于未经变质处理的Al-7Si合金,减小了90.6%和4.7%。合金抗拉强度由原来的168.1 MPa提升至209.1 MPa,增加了24.4%。同时伸长率从6.23%提升至9.62%,增长了54.4%。此外,合金的断裂方式也从脆性断裂转变为韧-脆混合断裂。In traditional casting of Al-Si alloys,the coarse dendriticα-Al phase and acicular eutectic Si strongly split the matrix,significantly compromising the mechanical properties.To refine the microstructure of Al-Si alloys and enhance their mechanical performance,the investigation focused on the influence of different additions of Y/Al-5Ti-1B modifiers(with Al-5Ti-1B held constant at 2 wt.%,and rare earth element Y varied at 0.05 wt.%,0.1 wt.%,0.2 wt.%,0.3 wt.%,0.4 wt.%,0.5 wt.%)on the microstructure and mechanical properties of Al-7Si alloy was conducted by scanning electron microscopy(SEM),electron probe microanalysis(EPMA),X-ray diffraction(XRD),and a universal materials testing machine.Furthermore,the modification mechanisms of Y/Al-5Ti-1B on an Al-7Si alloy were also explored.The results demonstrate that the optimal modification effect is achieved with 2 wt.%Al-5Ti-1B and 0.4 wt.%rare earth Y.The coarse needle-like eutectic Si transforms into fine granular structures,with lengths and widths reduced to 2.7 and 0.8μm,respectively.This represents significant decreases of 90.6%and 4.7%,respectively,compared to those of the unmodified alloy.The ultimate tensile strength(UTS)increases by 24.4%from 168.1 MPa to 209.1 MPa,while the elongation(EL)increases by 54.4%from 6.23%to 9.62%.The fracture mode of the alloy transforms from a typical brittle fracture to a ductile-brittle mixed fracture.

关 键 词：Al-7Si合金 Y/Al-5Ti-1B复合变质剂 共晶Si 微观组织 力学性能 

分 类 号：TG146.21[一般工业技术—材料科学与工程] TG113.25[金属学及工艺—金属材料]