选区激光烧结覆膜砂后处理固化工艺及性能研究  

Study on Post-treatment Curing Process and Properties of Selective Laser Sintered Coated Sand

作　　者：何明智 顿亚鹏 蒋芳[2] 唐星 李国彬 谢知航 He Mingzhi;Dun Yapeng;Jiang Fang;Tang Xing;Li Guobin;Xie Zhihang(School of Materials Science and Engineering,Hubei University of Automotive Technology,Shiyan,Hubei 442002,China;Hubei Cultural Industry Economic Research Center(Hubei University of Education),Wuhan 430205,China;Haixi(Fujian)Institute,China Academy of Machinery Science&Technology Co.,Ltd.,Sanming,Fujian 365500,China)

机构地区：[1]湖北汽车工业学院材料科学与工程学院,湖北十堰442002 [2]湖北文化产业经济研究中心(湖北第二师范学院),武汉430205 [3]中国机械总院集团海西(福建)分院有限公司,福建三明365500

出　　处：《机电工程技术》2023年第8期27-29,58,共4页Mechanical & Electrical Engineering Technology

基　　金：湖北文化产业经济研究中心开放基金(HBCIR2021006);湖北省非物质文化遗产研究中心开放基金(FY-2021-23);湖北文化创意产业化设计研究中心基金(HBCY2111);巴楚艺术发展研究中心基金(2022-BCYS-05);教育部高教司产学合作协同育人项目(201901091006);大学生创新创业训练计划项目(DC2020058)。

摘　　要：选区激光烧结覆膜砂是增材制造的一个重要分支,应用于快速制造覆膜砂铸型(芯),极大缩短传统砂型铸造产品的开发周期。通过选区激光烧结制备覆膜砂试样并进行了后处理强化,通过拉伸、压缩及抗弯实验测试其力学性能,通过扫描电镜及红外分析揭示固化特性。研究表明:酚醛树脂低温时第一次固化乌洛托品与游离酚、残留水分反应,氮原子上的化学键与线性酚醛树脂反应,缩聚为体型结构产物,随着温度升高,一次固化的二羟基苄胺与三羟基苄胺进一步分解形成体型结构达到二次固化,强度得到提升。在后处理中添加玻璃微珠,190℃下覆膜砂强度最大,抗拉强度能达到4.22 MPa。覆膜砂试样后处理190℃下固化较完全,断裂方式为内聚断裂及附着断裂共存,160℃及220℃下存在碗状断口,断裂方式为附着断裂。Selective laser sintering coated sand is an important branch of additive manufacturing,which is used to rapidly manufacture coated sand casting(core)and greatly shorten the development cycle of traditional sand casting products.The coated sand samples are prepared by selective laser sintering and strengthened by post-treatment.The mechanical properties are tested by tensile,compression and bending experiments.The curing characteristics are revealed by scanning electron microscopy and infrared analysis.Research has shown that phenolic resin for the first time when low temperature curing methenamine reaction and free phenol and water,the chemical bonds on the nitrogen atoms and linear phenolic resin reaction,condensation product for body structure,as the temperature increases,the decomposition of dihydroxybenzylamine and trihydroxybenzylamine gives methyramine,further formed shape structure to secondary curing,intensity is improved.When glass beads are added in the post-treatment,the strength of coated sand reaches the maximum at 190℃,and the tensile strength reaches 4.22 MPa.The coated sand samples are cured completely at 190℃,and the fracture mode is the coexistence of cohesive fracture and adhesion fracture.There are bowl-shaped fractures at 160℃and 220℃,and the fracture mode is adhesion fracture.

关 键 词：选区激光烧结 覆膜砂 后处理 固化反应 

分 类 号：TG242[金属学及工艺—铸造]