Zr-1Nb-0.1Fe-0.1Cu锆合金显微组织研究

Study on Microstructure of Zr-1Nb-0.1Fe-0.1Cu Zirconium Alloy

将海绵锆通过电极压制、真空自耗电弧熔炼、锻造、均匀化处理、淬火、热轧、多道次冷轧及退火制备出厚度为1.4 mm的Zr-1Nb-0.1Fe-0.1Cu板材样品。采用光学显微镜、扫描电镜及透射电镜研究分析Zr-1Nb-0.1Fe-0.1Cu合金金相组织及第二相的成分、大小、结构及分布。试验结果表明:经580℃/2 h成品退火的Zr-1Nb-0.1Fe-0.1Cu合金金相组织基本为再结晶等轴晶,晶粒度13级,平均晶粒尺寸小于6μm;合金晶内及晶界弥散析出呈椭圆形的第二相粒子,95%以上的第二相粒子尺寸小于200 nm;Zr-1Nb-0.1Fe-0.1Cu合金析出三种第二相粒子:含量较多、晶粒尺寸小于100 nm、体心立方结构的β-Nb析出相,含量较少、晶粒尺寸小于200 nm、密排六方结构的(Zr,Nb);Fe析出相以及含量最少、晶粒尺寸大于200 nm、四方结构的Zr_(2)Cu析出相。

Zr-1 Nb-0.1 Fe-0.1 Cu plate samples with a thickness of 1.4 mm were prepared with sponge zirconium by electrode pressing,vacuum consumable arc melting,forging,homogenization treatment,quenching,hot rolling,multi-pass cold rolling and annealing.The metallographic microstructure of Zr-1 Nb-0.1 Fe-0.1 Cu alloy and the composition,size,structure and distribution of the second phase were analyzed by OM,SEM and TEM.The test results show that the metallographic microstructure of Zr-1 Nb-0.1 Fe-0.1 Cu alloy annealed at 580℃for 2 h is basically recrystallized equiaxed crystal,the grain size grade is 13,and the average grain size is less than 6μm.Elliptical second-phase particles are precipitated and dispersed in the grains and grain boundary of the alloy.More than 95%of the second-phase particles have smaller size than 200 nm.There are three kinds of second-phase particles in Zr-1 Nb-0.1 Fe-0.1 Cu alloy,includingβ-Nb precipitate with a large content,a grain size of less than 100 nm,and bcc structure,(Zr,Nb)_(2)Fe precipitate with a less content,a grain size of less than 200 nm,and hcp structure,and Zr;Cu precipitate with the least content,a greater grain size than 200 nm,and tetragonal structure.