APT和萃取复型研究压力容器模拟钢中富Cu团簇的析出

来源期刊：金属学报2011年第3期

论文作者：楚大锋 徐刚 王伟 彭剑超 王均安 周邦新

文章页码：269 - 274

关键词：压力容器模拟钢； 富Cu原子团簇； 原子探针层析技术； 萃取复型； 高分辨透射电子显微镜

Key words：reactor pressure vessel model steel； Cu-rich cluster； atom probe tomography； extraction replica； high resolution transmission electron microscopy

摘    要：用原子探针层析技术(APT)和萃取复型方法研究了核反应堆压力容器模拟钢中富Cu原子团簇的析出.提高了Cu含量的压力容器模拟钢经过880℃水淬,再经过660℃/10 h调质处理,随后在370℃进行不同时间的时效处理,利用APT对时效4500 h的样品分析结果显示,样品中富Cu原子团簇的数量密度达到3.1×10²³m^-3.富Cu团簇大小在1-5 nm范围内时,随着团簇长大含Cu量也迅速增加.Ni和Mn除了在Cu团簇中发生偏聚外,还会在团簇的周围发生富集.用4%硝酸酒精溶液作腐蚀液可以将小至5 nm的富Cu团簇从α-Fe中萃取出来,HRTEM和EDS分析显示,富Cu团簇中存在孪晶结构,虽然大多数团簇是含Cu 10%-80%(原子分数)的Cu-Fe(Ni,Mn)合金,但都是9R或fcc结构的均匀固溶体.

Abstract: The precipitation of Cu-rich clusters in reactor pressure vessel (RPV) model steel was investigated by means of atom probe tomography (APT),extraction replica (ER) and HRTEM. RPV model steel was prepared by vacuum induction furnace melting with higher content of Cu (0.6%, mass fraction).The ingot (about 50 kg of weight) was forged and hot-rolled to 4 mm in thickness and then cut to specimens of 40 mm×30 mm.Those specimens were further heat treated by 880℃/0.5 h water quenching and 660℃/10 h tempering,and finally aged at 370℃ for different time from 1000 to 6000 h.4% nitric acid alcohol solution was used as an etchant to extract the precipitates of Cu-rich clusters fromα-Fe matrix.The results obtained by APT analysis show that the number density of Cu-rich clusters reaches 3.1×10²³m^-3 in the specimen aged at 370℃for 4500 h,and the Cu content in the clusters increases rapidly during their growth from 1 nm to 5 nm.The segregation of Ni and Mn elements within and around the Cu-rich clusters was detected.The results obtained by ER,EDS and HRTEM analyses show that the majority of Cu-rich clusters are Cu-Fe(Ni,Mn) alloys with 10%—80%Cu (atomic fraction),but they are a single phase with 9R or fcc crystal structure.