高剂量氦离子辐照对新型中子增殖铍钨合金表面结构的影响  

Effect of high dose helium ion irradiation on the surface microstructure of a new neutron multiplying Be-W alloy

作　　者：刘平平[1] 胡文 宋健 贾玉梅 詹倩[1] 万发荣[1] LIU Ping-ping;HU Wen;SONG Jian;JIA Yu-mei;ZHAN Qian;WAN Fa-rong(School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学材料科学与工程学院

出　　处：《工程科学学报》2020年第1期128-133,共6页Chinese Journal of Engineering

基　　金：国家自然科学基金资助项目(U1637210,11775018,51601012)

摘　　要：为了确保未来核聚变反应堆的氘氚自持燃烧必需采用中子增殖材料来得到合适的氚增值比.金属铍被认为是最有前途的核聚变反应堆固态中子倍增材料,但其熔点低,高温抗辐照肿胀性能差,因此需要寻找和研发具有更高熔点和更耐辐照肿胀的新型中子增殖材料以满足更先进的聚变堆要求.本研究尝试提出并制备了一种更高熔点的铍钨合金(Be12W),通过X射线和扫描电子显微镜对它的相组成和表面结构进行分析.对新型铍钨合金进行高剂量的氦离子辐照,发现合金表面一次起泡的平均尺寸约为0.8μm,面密度约为2.4×10^7 cm^-2,而二次起泡的平均尺寸约为80 nm,面密度约为1.28×10^8 cm^-2.分析氦辐照引起的表面起泡及其机制,并与纯铍和铍钛合金表面起泡的情况进行了对比.A neutron multiplier must be employed to obtain the proper tritium breeding rate and ensure the self-sustaining combustion of deuterium and tritium in fusion reactors,which represents a new and powerful solution for the energy problem.Several researchers have proposed the use of beryllium,an outstanding nuclear metal,as a promising solid neutron multiplier in the heliumcooled ceramic breeder(HCCB)test blanket module(TBM)of the Chinese TBM program.In this module,beryllium will be subjected to high-dose irradiation with high-energy neutrons during services in reactor to produce a large number of helium ions and significant irradiation damage resulting in extreme performance degradation.Unfortunately,the metal’s low melting point and poor irradiation swelling resistance at high temperatures limit its usage in the DEMO reactor.Thus,finding or developing a new neutron multiplier with a higher melting point and better ability to resist irradiation swelling than beryllium in advanced fusion reactors is an important undertaking.Knowledge of the characteristics of the microstructural changes of beryllium and/or beryllium alloys under irradiation is an important factor contributing to the understanding of the degradation of their physical-mechanical properties.In this study,a new beryllium tungsten alloy(Be12W)with a high melting point was proposed and fabricated by hot isostatic pressing.The phase composition and surface structure of Be12W were then analyzed by X-ray and scanning electron microscopy.The Be12W alloy was irradiated with 30 keV He+ions at room temperature at a dose of 1×10^18 ions·cm^-2 and ion fluence of 0.2μA.Microstructural changesand the types of helium gas-filled blisters that developed on the surface of the alloy after irradiation were subsequently investigated.Blisters with an average size of 0.8μm and in-plane number density of 2.4×10^7 cm^-2 initially develops,followed by blisters with an average size of about 80 nm and in-plane number density of 1.28×10^8 cm^-2.

关 键 词：氚自持 中子增殖 氦泡 铍金属间化合物 核聚变 

分 类 号：TG146.4[一般工业技术—材料科学与工程] O469[金属学及工艺—金属材料]