摘要
通过退火组织及第二相粒子观测、电化学腐蚀测试和腐蚀形貌分析,研究了退火温度对冷轧工业级锆合金板材组织和第二相粒子的影响。研究发现,470℃退火后板材组织以形变组织为主,其电化学耐腐蚀性能最差;500℃及以上的退火板材形成完全再结晶组织,在该组织中第二相粒子数量和尺寸对锆合金在硝酸介质中的腐蚀性能具有显著影响。500℃退火温度下锆合金析出的第二相粒子数量较少,且尺寸较细;550℃退火温度下合金第二相粒子数量和尺寸均有所增加;退火温度升高至600℃时,合金第二相粒子数量变化较小,但尺寸粗化明显,且样品自腐蚀电位E_(corr)较低,出现钝化膜反复击穿与修复现象,表面腐蚀坑最多且尺寸较大。粗大的第二相粒子在硝酸介质电化学腐蚀中会优先发生腐蚀,因此需在保证形成完全再结晶组织的同时,控制低退火温度条件以获得细小的第二相粒子,从而提升锆合金在硝酸中的耐腐蚀性能。本实验中500℃退火的锆合金样品第二相颗粒细小且数量较少,其耐腐蚀性能最优。
The effect of annealing temperature on the microstructure and second-phase particles of coldrolled industrial zirconium alloy plate was studied by means of annealing microstructure and second-phase particle observation,electrochemical corrosion test and corrosion morphology analysis.It is found that the microstructure of the plate after annealing at 470℃is mainly deformed microstructure,and its electrochemical corrosion resistance is the worst.After annealing at 500℃and above,a completely recrystallized microstructure is formed in the plate,where the number and size of second-phase particles have a significant influence on the corrosion resistance of zirconium alloy in nitric acid medium.At the annealing temperature of 500℃,the number and size of second-phase particles precipitated from zirconium alloy are small.At the annealing temperature of 550℃,the number and size of second-phase particles in the alloy increases.When the annealing temperature rises to 600℃,the number of second-phase particles in the alloy changes little,but the size coarsens obviously.The sample annealed at 600℃has low self-corrosion potential E_(corr),its passivation film is repeatedly broken down and repaired,and there are the most corrosion pits with relatively large size on the surface of the sample.Coarse second-phase particles are preferentially corroded in nitric acid medium,so it is necessary to control the low annealing temperature while the formation of completely recrystallized microstructure is ensured,to obtain fine second-phase particles and then improve the corrosion resistance of zirconium alloy in nitric acid.In this experiment,the zirconium alloy sample annealed at 500℃has fine second-phase particles with small number and the best corrosion resistance.
作者
严宝辉
崔春娟
肖颖
YAN Bao-hui;CUI Chun-juan;XIAO Ying(School of Metallurgical Engineering,Xi'an University of Architecture and Technology,Xi'an 710055,China;Xi'an Western Energy Material Technologies Co.,Ltd.,Xi'an 721299,China)
出处
《稀有金属与硬质合金》
CAS
CSCD
北大核心
2024年第6期69-74,88,共7页
Rare Metals and Cemented Carbides
基金
陕西省重点研发计划重点产业创新链(群)项目(2019ZDLGY04-04)
中国原子能“燎原计划”科研项目(20221101)。
关键词
锆合金
第二相粒子
电化学腐蚀
极化曲线
腐蚀形貌
退火温度
zirconium alloy
second-phase particle
electrochemical corrosion
polarization curve
corrosion morphology
annealing temperature
