摘要
使用高温激光共聚焦扫描显微镜原位观察了含0.016%(质量分数,下同)的La和不含La的低合金高强钢模拟焊接热影响区中高温阶段奥氏体的长大和组织转变行为,并使用光学显微镜和电子扫描显微镜对比分析了添加0.016%的La对粗晶热影响区晶粒细化的影响。结果表明:添加0.016%的La使低合金高强钢中的夹杂物由Al-Mg-O、(Mn,Ca)S和Ti N复合夹杂物演变为La2O2S,这种夹杂物与铁素体的晶格错配度较低,能促进针状铁素体的形成。同时,在添加0.016%La的钢中生成了更多细小弥散的(Ti,Nb)(C,N)析出物,在模拟焊接热循环过程中能钉扎粗晶热影响区奥氏体晶界抑制晶粒长大。这表明,含0.016%La的低合金高强钢中粗晶热影响区的晶粒更为细小。
The processes of austenite growth and microstructure transformation in the simulated coarse-grain heat-affected zone(CGHAZ)for high strength low alloy steels without and with 0.016%La addition were in-situ observed by means of high temperature laser confocal scanning microscope.The grain refinement in CGHAZ of the steel with 0.016%La was also assessed by using optical-and electronmicroscopy.The results show that the complex inclusions of Al-Mg-O,(Mn,Ca)S and TiN may transform to La2 O2 S in CGHAZ of the steel due to the addition of 0.016%La.La2 O2 S had lower mismatch withα-Fe,which can effectively promote the formation of acicular ferrites.Meanwhile,many finer dispersed(Ti,Nb)(C,N)precipitates formed in 0.016%La-containing steel can effectively pin the austenite grain boundary,inhibiting the grain growth.Thus,the grains in CGHAZ of 0.016%La-containing steel became finer.
作者
周峰
曹羽鑫
万响亮
ZHOU Feng;CAO Yuxin;WAN Xiangliang(School of Mechanical and Electrical Engineering,Foshan Polytechnic,Foshan 528237,China;Band(Foshan)Metallic Composite Materials Co.,Ltd.,Foshan 528000,China;Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,China)
出处
《材料研究学报》
EI
CAS
CSCD
北大核心
2021年第3期231-240,共10页
Chinese Journal of Materials Research
基金
广东省自然科学基金(2019A1515011828,2018A030313287)
广东省教育厅高校创新团队(2019GKCXTD005)。
关键词
金属材料
晶粒细化
原位观察
镧
高强度低合金钢
粗晶热影响区
metallic materials
grain refinement
in-situ observation
La
high strength low alloy steel
coarse-grain heat-affected zone
