在线稳恒磁场对激光选区熔化成形GH3536组织和性能各向异性的影响  

Effects of Online Static Magnetic Field on Anisotropy of Microstructure and Mechanical Properties of GH3536 Fabricated bySelective Laser Melting

作　　者：程坦 张振雨 刘演冰 滕庆 陈辉[1,2] 李伟 魏青松 Cheng Tan;Zhang Zhenyu;Liu Yanbing;Teng Qing;Chen Hui;Li Wei;Wei Qingsong(State Key Laboratory of Material Processing and Die&Mould Technology,School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan,Hubei 430074,China;Department of Mechanical Engineering,National University of Singapore,Singapore 117575,Singapore;Key Laboratory of Metallurgical Equipment and Control Technology of Ministry of Education,Wuhan University of Science and Technology,Wuhan,Hubei 430081,China;Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering,Wuhan University of Science and Technology,Wuhan,Hubei 430081,China;Precision Manufacturing Institute,Wuhan University of Science and Technology,Wuhan,Hubei 430081,China)

机构地区：[1]华中科技大学材料科学与工程学院材料成形与模具技术国家重点实验室,湖北武汉430074 [2]新加坡国立大学机械工程学院,新加坡117575,新加坡 [3]武汉科技大学冶金装备及其控制省部共建教育部重点实验室,湖北武汉430081 [4]武汉科技大学机械传动与制造工程湖北省重点实验室,湖北武汉430081 [5]武汉科技大学精密制造研究院,湖北武汉430081

出　　处：《中国激光》2022年第8期178-188,共11页Chinese Journal of Lasers

基　　金：国家自然科学基金(51775207);华中科技大学学术前沿青年团队资助项目(2017QYTD06)。

摘　　要：研究了外加在线稳恒磁场对激光选区熔化(Selective Laser Melting,SLM)成形GH3536合金组织及力学性能各向异性的影响。设计了可作用于激光选区熔化成形台面的在线磁场发生装置,可产生最大强度为0.3T、竖直向上的稳恒磁场。当无磁场和施加0.1T、0.3T磁场时,对成形试样进行了微观表征和拉伸试验。结果表明:随着磁场强度的增加,试样致密度由96.4%升高至98.8%,晶粒取向逐渐由强(001)取向转变为(001)、(101)和(111)的均匀取向。在0.1T磁场下,试样沿沉积方向的织构指数由6.843下降至6.363;在0.3T磁场下,织构指数下降至5.718。在稳恒磁场的作用下,试样沿扫描和沉积方向的抗拉强度及延伸率差异有明显改善。在0.1T磁场下,强度和延伸率差异相对于无磁场时分别减小了14.1%和11.1%;在0.3T磁场下,则减小了47.5%和55.3%。理论分析与计算认为,晶粒取向和性能各向异性的改变主要是由于外加磁场产生了10^(5)N/m^(3)量级的热电磁力,进而枝晶生长方向发生改变。Objective The heat transfer is downward along the solidified substrate during the selective laser melting(SLM)process and results in the bottom-up growth of columnar crystals.The oriented columnar structure causes the anisotropy in the mechanical properties of materials and hinders the application of SLM.For this reason,many researchers have studied the causes and suppression methods of the anisotropy of SLM parts,mainly from the perspectives of heat treatment and SLM process.However,both heat treatment and SLM adjustment have certain limitations.Heat treatment requires new exploration for different materials,however the adjustment of the SLM process cannot change the nature of the directional heat transfer in the melt pool.The application of electromagnetic fields is an effective way to influence the metal solidification process.Recent studies have found that magnetic fields can induce the microstructures of SLM parts to change from columnar to equiaxed crystals,thus improving their mechanical properties.However,in general,the studies on the influence of magnetic fields on the microstructures of SLM parts are very limited,and the mechanism of a magnetic field influences the SLM process is still unclear.In particular,there are not studies involving the influence of magnetic fields on the anisotropy of SLM parts.In this paper,a device for generating a static magnetic field is built.Using GH3536,a typical aerospace material,as a representative material,we investigate the influence of a static magnetic field on the microscopic and macroscopic properties of the SLM-formed GH3536 parts,especially the influence of magnetic fields on the anisotropy of the parts.This study provides a theoretical and technical reference on the potential of using a superimposed magnetic field during the SLM process and the associated benefits to improve the performance of SLM parts.Methods In this paper,a static magnetic field generator that can be integrated into the self-developed equipment in our research group to generate a static magn

关 键 词：激光技术 激光选区熔化 稳恒磁场 各向异性 GH3536 

分 类 号：TG146.1[一般工业技术—材料科学与工程]