核燃料U-50%Zr合金的组织及热变形行为  

Microstructure and hot deformation behavior of U-50%Zr alloy for nuclear fuel

作　　者：李岩峰 郭洪 李明阳[1,2] 胡秉坤 刘建成 Li Yanfeng;Guo Hong;Li Mingyang;Hu Bingkun;Liu Jiancheng(CNNC Key Laboratory on New Materials Research and Application Development,Baotou Inner Mongolia 014035,China;China North Nuclear Fuel Co.,Ltd.,Baotou Inner Mongolia 014035,China)

机构地区：[1]中核新型材料研究与应用开发重点实验室,内蒙古包头014035 [2]中核北方核燃料元件有限公司,内蒙古包头014035

出　　处：《金属热处理》2025年第2期29-36,共8页Heat Treatment of Metals

基　　金：中核集团集中研发项目(中核科发[2022]160号)。

摘　　要：通过高频感应熔炼制备了核燃料U-50%Zr合金,利用金相显微镜和X射线衍射仪对其组织和物相进行了分析,利用Gleeble-3800热模拟试验机进行不同变形温度(500、550和600℃)和应变速率(0.01、0.1和1 s^(-1))下的热压缩试验,研究其热变形行为。结果表明,除变形温度600℃、应变速率为0.01 s^(-1)外,其他变形条件下,U-50%Zr合金表现出明显的加工硬化特征。相同应变速率下,峰值应力随变形温度的升高而降低,特别是在600℃时,峰值应力相比于500℃和550℃降低明显;相同变形温度下,峰值应力随应变速率的增大而升高。U-50%Zr合金经热变形后,组织并未发生相变,均为δ-UZr_(2)相;随热变形温度的升高,晶粒尺寸先基本不变随后增大,500、550℃时晶粒尺寸均在250μm左右,600℃时,晶粒尺寸明显长大,达到493μm。基于峰值应力,通过Arrhenius模型与温度补偿因子Z参数,建立了U-50%Zr合金的本构方程,其热变形激活能Q=694.9 kJ/mol。通过DMM动态材料模型构建了热加工图,并确定了合适的加工区间为:变形温度540℃以上,应变速率0.01~1 s^(-1)。U-50%Zr alloy for nuclear fuel was prepared by high-frequency induction melting,and its microstructure and phase constituent were analyzed using metallographic microscope and X-ray diffractometer.The Gleeble-3800 thermal simulation test machine was used to conduct hot compression tests at different deformation temperatures(500,550 and 600℃)and strain rates(0.01 s,0.1 and 1 s^(-1))to investigate its hot deformation behavior.The results show that,except for a deformation temperature of 600℃and a strain rate of 0.01 s^(-1),the U-50%Zr alloy exhibits significant work hardening characteristics under other deformation conditions.At the same strain rate,the peak stress decreases with the increase of deformation temperature,especially at 600℃,where the peak stress decreases significantly compared to 500℃and 550℃.At the same deformation temperature,the peak stress increases with the increase of strain rate.After hot deformation,no phase transformation occurs in the microstructure,all of which areδ-UZr_(2)phase.As the hot deformation temperature increases,the grain size of the alloy initially remains basically unchanged and then increases.At 500℃and 550℃,the grain size is around 250μm,and at 600℃,the grain size significantly increases to 493μm.Based on peak stress,the constitutive equation of U-50%Zr alloy is established using the hyperbolic sine function Arrhenius model and temperature compensation factor Z parameter,with a hot deformation activation energy Q=694.9 kJ/mol.A hot working map is constructed using DMM dynamic material model,and the appropriate processing range is determined as follows:deformation temperature above 540℃,strain rate between 0.01 s^(-1)and 1 s^(-1).

关 键 词：核燃料U-50%Zr合金 热压缩变形 本构方程 热加工图 组织 

分 类 号：TG146.8[一般工业技术—材料科学与工程]