Si元素对11.5CrMoxSi铁素体马氏体钢第二相组织演变的影响  

Effect of Si Element on Second Phase Evolution of 11.5CrMoxSi Ferritic-martensitic Steel

作　　者：陈国清[1] 杨俭 王清[1] 周文龙[1] 唐睿[2] CHEN Guoqing;YANG Jian;WANG Qing;ZHOU Wenlong;TANG Rui(School of Materials Science and Engineering,Dalian University of Technology,Dalian 116085,China;Laboratory of Science and Technology on Reactor Fuel and Materials,Nuclear Power Institute of China,Chengdu 610041,China)

机构地区：[1]大连理工大学材料科学与工程学院辽宁省凝固控制与数字化制备技术重点实验室,辽宁大连116085 [2]中国核动力研究设计院反应堆燃料及材料重点实验室,四川成都610041

出　　处：《热加工工艺》2020年第24期41-46,共6页Hot Working Technology

基　　金：国家国际科技合作专项项目(2015DFR60370);中央高校基本科研业务费资助项目(DUT17GF209)。

摘　　要：铁素体马氏体钢(FM钢)是高性能快堆燃料包壳的候选材料。设计了Si含量分别为0.6%、0.9%、1.2%和1.5%的11.5CrMoXSi铁素体马氏体钢,研究了Si元素在老化过程中对铁素体马氏体钢第二相组织的影响。结果表明,Si含量影响组织中M23C6和Laves相的数量和分布,进而影响材料的力学性能。Si含量为0.6%时,M23C6碳化物倾向于在晶粒内弥散析出,对材料基体的强度有很好的提升,但随着老化进行,M23C6互相吞并长大,逐渐失去弥散强化作用;当Si含量达到1.5%时,M23C6相倾向于在晶界处分布,随着老化进行其数量和分布保持相对稳定。此外,Si元素会在M23C6相附近的微晶界处聚集,促进Laves相的生成,且其数量、大小和体积分数不断增加,强化作用明显。老化之前,Si含量较低的材料,其硬度和抗拉强度更高,老化初期的50 h内,低Si含量FM钢的硬度和抗拉强度迅速降低;而Si含量为1.5%的FM钢硬度保持稳定,抗拉强度略有提升。Ferritic-martensitic steel(FM steel) is an important candidate material for high performance fast reactor fuel cladding. 11.5CrMoxSi ferritic-martensite steels with Si content of 0.6%, 0.9%, 1.2% and 1.5% were designed to investigate the effect of Si addition on the second phase during the aging. The results demonstrate that Si content affects the amount and distribution of M23C6 and Laves phase, which can affect the mechanical properties of the material. When Si content is 0.6%,M23C6 carbides disperse within the grain, which greatly improve the strength of the material. However, M23C6 grows up during the aging process and gradually loses the diffusion strengthening effect. When Si content reaches 1.5%, M23C6 carbides distribute at grain boundaries, and their quantity and distribution remain relatively stable during aging. In addition, Si element gathers at the micrograin boundary near M23C6 carbide, promoting the formation of Laves phase. And the number, size and volume fraction of Laves phase would continuously increase with aging, which can enhance the hardness and tensile strength of the material. Before the aging, the hardness and tensile strength of the materials with lower Si content are higher, and the hardness and tensile strength of the FM steel with lower Si content rapidly decreases within 50 h at the initial aging stage;the hardness of FM steel with Si content of 1.5% remains stable and its tensile strength slightly improves.

关 键 词：铁素体马氏体钢 老化 M23C6 LAVES相 

分 类 号：TG142.11[一般工业技术—材料科学与工程]