电磁搅拌对TiB2颗粒增强钢组织和力学性能的影响  

Effect of Electromagnetic Stirring on Microstructure and Mechanical Properties of TiB Particle-Reinforced Steel

作　　者：张林[1] 郭晓 高建文 邓安元[1] 王恩刚[1] ZHANG Lin;GUO Xiao;GAO Jianwen;DENG Anyuan;WANG Engang(Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education),Northeastern University,Shenyang 110819,China;School of Metallurgy,Northeastern University,Shenyang 110819,China)

机构地区：[1]东北大学材料电磁过程研究教育部重点实验室,沈阳110819 [2]东北大学冶金学院,沈阳110819

出　　处：《金属学报》2020年第9期1239-1246,共8页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目No.51674083;高等学校学科创新引智计划项目2.0 No.BP0719037。

摘　　要：在立式线型电磁搅拌器的作用下凝固制备TiB2颗粒增强钢,研究了电磁搅拌对组织中的颗粒形态和尺寸分布,以及对材料的Vickers硬度分布和拉伸力学性能的影响。结果表明,电磁搅拌有效地细化了颗粒增强钢中的初生TiB2颗粒尺寸,颗粒平均尺寸随励磁电流的上升而逐步减小。较高的励磁电流下颗粒的分布更均匀弥散,且去除了颗粒周围的裂缝缺陷。电磁搅拌降低了TiB2颗粒增强钢的宏观偏析,减小了铸锭中不同高度组织的硬度差。较大的励磁电流有助于提高材料的平均硬度,在350 A励磁电流下硬度达到275 HV。电磁搅拌可提高TiB2颗粒增强钢的抗拉强度和断裂应变,励磁电流为350 A时,抗拉强度达到520.2 MPa,断裂应变约为8.5%。颗粒细化的主要原因是受到电磁搅拌下的熔体流动冲击和电磁力的作用。理论分析了颗粒所受电磁力的影响因素,电磁力随磁场强度升高而增大,随熔体温度的上升而减小,随颗粒尺寸的增加而增大。TiB2 is a promising strengthening phase in steels applying in lightweight transportation systems due to its high Young’s modulus and low density. However, the density difference between TiB2 particles and matrix leads to segregation during solidification. TiB2 particle-reinforced steels were solidified with a vertical linear-type electromagnetic stirring device. The effects of electromagnetic stirring on the morphology and size distribution of TiB2 particles were studied. Vickers hardness, mechanical properties in the tensile test were also discussed. The results show that electromagnetic stirring effectively refined the primary TiB2 particles in the steel, and the average particle size decreased with the increase of exciting current. The particles distributed dispersively and the structure was more homogenous under a higher exciting current. Besides, the defects of crackle around particles were eliminated under high current. Electromagnetic stirring reduced the macrosegregation of TiB2 particle-reinforced steels, which decreased the hardness discrepancy in the ingot at various heights. A higher exciting current attributed to higher average hardness, and the steel reached a hardness of 275 HV under 350 A exciting current. The ultimate tensile strength and the strain at break were both enhanced by electromagnetic stirring, and reached 520.2 MPa and 8.5% respectively under an exciting current of 350 A. The refinement of particles was caused by the smashing process under a strong convection driven by the moving magnetic field, and the effect of electromagnetic force acting on the particles. The influence factors of electromagnetic force were analyzed, which show the force increases with increasing magnetic intensity, decreases with increasing temperature of melt, and increases with increasing particle size.

关 键 词：电磁搅拌 TiB2颗粒增强钢 硬度 抗拉强度 

分 类 号：TG142.1[一般工业技术—材料科学与工程]