稀土对含铜钢等温时效过程硬度与显微组织演变的影响  

Effect of Rare Earth on Hardness and Microstructure Evolution of Copper-Bearing Steel During Isothermal Aging

作　　者：魏慧慧 王海燕[1] 高雪云[1] 智建国[2] 张羊换[1] Wei Huihui;Wang Haiyan;Gao Xueyun;Zhi Jianguo;Zhang Yanghuan(School of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou 014010,China;Inner Mongolia Baotou Steel Union Co.,Ltd.,Key Laboratory of Rare Earth Steel Product R&D Enterprise of Inner Mongolia Autonomous Region,Baotou O14010,China)

机构地区：[1]内蒙古科技大学材料与冶金学院,内蒙古包头014010 [2]内蒙古包钢钢联股份有限公司,内蒙古自治区稀土钢产品研发企业重点实验室,内蒙古包头014010

出　　处：《中国稀土学报》2024年第2期315-321,I0005,共8页Journal of the Chinese Society of Rare Earths

基　　金：国家自然科学基金项目(51961030);中央引导地方科技发展资金项目(2020ZY0034)资助。

摘　　要：对不同含量La含铜HSLA钢进行900℃淬火、550℃等温时效热处理,利用光学显微镜、场发射扫描电镜和透射电镜观察组织及析出相形貌,结合硬度测试结果,探索其硬度变化趋势及显微组织演变规律,并讨论了La对试验钢硬度、显微组织及析出相的影响。结果表明,随着时效时间的延长,试验钢的硬度先增大后减小;试验钢的硬度随La含量的增加先增大后减小,添加0.005%La可以显著提高试验钢的硬度。试验钢淬火组织为马氏体和贝氏体混合物,等温时效后组织为回火马氏体;La可以显著细化板条结构。未添加稀土的试验钢中富Cu析出相弥散分布在基体上,添加稀土的试验钢中富Cu析出相主要在位错及板条界面处析出。试验钢的最终硬度由显微组织及富铜析出相协同决定。The copper-containing HSLA steels with different La contents were quenched at 900°C and isothermal aging heat treatment at 550 C.The microstructure and precipitation phase of the tested steel were observed by an optical microscope,a field emission scanning electron microscope and a transmission electron microscope.Combined with the hardness test results,the hardness change trend and microstructure evolution were explored.The influence of La on the hardness,microstructure and precipitation of the tested steel was discussed.The results show that with the prolongation of aging time,the hardness of the tested steel increases firstly and then decreases.The hardness of the tested steel increases firstly and then decreases with the increase of La content.Adding 0.005%La can significantly improve the hardness of the test steel.The quenched microstructure of the tested steel is a mixture of martensite and bainite,and the microstructure after isothermal aging is tempered martensite;La can significantly refine the lath structure.The Cu-rich precipitates in the tested steel without rare earth are diffusely distributed on the matrix,and the Cu-rich precipitates in the tested steel with rare earth are mainly precipitated at the interface of dislocations and laths.The final hardness of the tested steel is determined by synergistic effects of microstructure and copper-rich precipitates.

关 键 词：稀土La 含铜钢 等温时效 硬度 显微组织 

分 类 号：TG142.1[一般工业技术—材料科学与工程]