Z-pinch靶用氘代聚苯乙烯丝的研制及表征

为满足Z-pinch D-D出中子实验对固体燃料容器的要求,设计了1套简易的拉丝装置,并用聚苯乙烯(PS)为原料进行了工艺条件实验,确定出较佳的实验条件。以1 g氘代聚苯乙烯(DPS)为原料,在确定出的实验条件下,控制合适的拉丝速度,可拉出直径为30~100μm、均匀、具有一定强度的DPS丝。所制备的DPS丝在Z-pinch D-D出中子实验中得到了应用,取得了最大中子产额为2×109cm-1的实验结果。     

全氘代低密度微孔聚苯乙烯泡沫的制备

采用聚合物溶液的热致相分离和冷冻干燥技术，制备了具有开放网络状孔洞结构的全氘代低密度、微孔聚苯乙烯泡沫。该全氘代聚苯乙烯泡沫密度为0．02～0．2g／cm^3，对应的平均孔径为10～0．2μm，氘代率大于98％。泡沫形貌结构的分析结果表明，泡沫结构取决于氘代聚苯乙烯溶液的相分离过程。     

乳液微封装技术制备聚苯乙烯空心微球

介绍了乳液微封装技术制备不同直径空心聚苯乙烯微球的工艺技术,着重研究了表面活性剂、电解质、水溶性聚合物对多重乳液的稳定性、微球的直径以及微球表面光洁度的影响。在选定的实验参数下,制备得到直径150～3000μm,壁厚0.8～15μm,表面粗糙度Ra约为4nm,微球同心度≥95%的空心聚苯乙烯微球。     

聚合物空心微球密度匹配法制备工艺研究

以聚苯乙烯（PS）为成球材料,研究了聚合物空心微球密度匹配法制备工艺中的油相（O相）有机溶剂各及配比、O相固化温度及时间、各相溶液中固体颗粒杂质、球内封装水（W1相）的置换等因素对产品微球质量的影响。制得了直径100－500μm、壁厚2－20μm、球形度≥99％、同心度相对偏差≤5％、表面粗糙度≤20nm的PS空心微球。     

ICF分解实验中的平面调制靶和薄膜靶的研制

本工作研制了用于惯性约束聚变ICF分解实验模拟聚变靶丸表面粗糙度和驱动激光空间不均匀性对R—T不稳定性作用的平面调制靶和平面薄膜靶。以激光干涉法结合图形转移工艺获得波长20～100μm、振幅0．0～4．0μm的正弦调制图形的模板,再将调制图形转移至溴代聚苯乙烯薄膜表面,制备出ICF实验用溴代聚苯乙烯平面调制箔靶;以半导体工艺结合自截止腐蚀工艺制得厚度4μm左右的自支撑Si平面薄膜靶。Si膜的表面粗糙度为几十纳米。对所研制的两种靶型的参数进行了测量。     

高剂量γ辐照对SEBS／PS共混物性能的影响

研究了高剂量(0～2.0 MGy)γ辐照对不同配比苯乙烯一-乙烯-丁烯-苯乙烯嵌段共聚物/聚苯乙烯(SEBS/PS)共混物(100/0～50/50)力学性能、电性能以及热稳定性能的影响.结果表明,PS的加入,可以有效改善SEBS的辐照稳定性.PS的含量越高,辐照后SEBS/PS共混物的拉伸强度、体积电阻率的下降幅度越小,介电损耗因子的上升幅度越小,热稳定性能越好.但PS的加入减少了共混物中聚烯烃相的含量,使得共混物的断裂伸长率受辐照的影响较大,特别在高剂量辐照后,PS的含量越高的共混物断裂伸长率下降越明显.     

炉内成球技术制备PS-PVA双层球

本工作研究采用炉内成球技术制备惯性约束聚变用靶丸聚苯乙烯-聚乙烯醇（PS-PVA）双层球。以乳液法制备PS微球，利用炉内成球技术在PS微球表面制备PVA层。研究表明，在PVA质量浓度为5％、炉内为空气、炉温473～523K条件下，可制备出PS-PVA双层球。双层球直径范围250～550μm，PVA层厚度范围1.0～2.4μm，PS-PVA双层球表面光洁度3～10nm，微球充氩气的最低温度350～360K，室温条件下对氘气的保气半寿命1～5h。     

电解抛光法制备超细钼丝及其表征

研究利用交流电解抛光技术制备用于惯性约束聚变Z-pinch物理实验的超细钼丝。实验研究了电解液浓度、温度、电解电压和腐蚀时间对制备超细钼丝的直径、表面状态和钼丝抗拉强度的影响,并用电阻法和扫描电镜、原子力显微镜表征了钼丝直径和表面形貌,用数字测力仪测定了钼丝的强度。测试结果表明,采用该技术能制备出5~15μm的超细钼丝。     

内表面掺硫聚苯乙烯空心微球初步研制

以聚苯乙烯磺酸钠（PSS）为掺杂源,采用乳液微封装法制备内表面掺S的聚苯乙烯（PS）空心微球。XPS测量表明,微球内表面存在明显的S元素。利用低能X射线照相技术研究了不同掺杂源浓度下干燥时重力和表面张力对掺杂均匀性的影响,当掺杂源浓度降为0.2%时,得到了内表面掺杂S均匀的PS微球,微球直径为200～800μm,直径300μm的微球中掺杂层S原子面密度为8.57×10⁶μm^－2。     

高精度漂移室的铝场丝蠕变效应的研究

报道了对铝场丝蠕变效应研究的结果。铝丝有蠕变效应,不同丝只是显示的效效大小不同, 相比而言,Φ100μm的镀银铝丝效应较小,在低动量高精度漂移室的建造中用作场丝是好的候选者。     

Unexpected behaviour of polystyrene-based scintillating fibers during irradiation at low doses and low dose rates

The time dependence of the optical radiation damage process was studied for different fibers with polystyrene (PS) core. The fibers were irradiated with X-rays. In the present experiment the light guide BCF-98 (Bicron, clear polystyrene) was compared with the two scintillating fibers SCSF-38 and SCSF-81 (Kuraray). The light transmission through the fiber was investigated before, during and after irradiation. All investigated fibers showed unexpected effects depending on the fiber type: (1) at low doses the scintillating fibers are more sensitive to radiation than at high doses, i.e. the optical absorption rises nonlinearly with dose; (2) shortlived optical absorption centers decaying within several hours were detected in all fibers with PS core investigated up to now. Especially for SCSF-81, the annealing part is large and it totally overlaps the emission spectrum of the fiber.     

Studies on irradiation stability of polystyrene by NMR

The irradiation stability of polystyrene (PS) was studied by ^13C and ^1H NMR spectra, Nuclear Overhauser Relaxation (NOE) and ^13C NMR spin-lattice relaxation time (T1). The results indicate that ^13C and ^1H NMR chemical shifts, NOE and T1 were almost invariant with the increase of irradiation dose. This shows that polystyrene is particularly stable within 2.5 kGy doses and the mechanism of its stability is discussed.     

Overview of the testing activities on ITER sub-scale pre-compression rings

After a first R&D and testing activity to develop and characterize by tensile and creep tests a high strength glass fiber-epoxy composite as reference material for the manufacture of ITER pre-compression rings, ENEA designed and manufactured a dedicated testing facility and different sub-scale composite ring mock-ups in order to characterize their mechanical properties.The paper reports the results of the overall testing activities performed during the last years on a total number of eleven sub-scale pre-compression ring mock-ups manufactured by winding S2 glass fibers on a diameter of 1 m (1/5 of the full scale) both by vacuum pressure epoxy impregnation (VPI) and filament wet winding techniques (WW).The first three rings were manufactured by ENEA Frascati thanks to a particular VPI technique; one of them was used as base composite material to manufacture different sets of specimens for shear, compression and non destructive tests (NDT). Then, five other mock-ups were manufactured following ENEA VPI process and three using WW technique by two different industrial companies.The rings were tested in ENEA Frascati in a dedicated hydraulic testing machine consisting of 18 radial actuators working in position control with a total load capability of 1000 tons. The complete testing campaign consisted of six ultimate tensile strength (UTS) tests and four stress relaxation (SR) tests.The tests demonstrated that the composite (S2 glass-epoxy) is a valid and viable solution for the ITER pre-compression rings (non conductive, non magnetic, capable to work at high stress level without relaxation).UTS tests showed an overall average ultimate strength of 1550 MPa (mean hoop stress in the cross section) and a constant hoop modulus to failure of all the mock-ups. Stress relaxation tests did not show any significant relaxation at different stress levels and durations.     

氧化物弥散强化低活化合金的微观组织及力学性能

为了强化低活化合金(CLF-1)的高温性能,将采用Ar气超声雾化方法制备的CLF-1粉末与纳米Y₂O₃粉末混合后,经高能球磨和热等静压处理,获得氧化物弥散强化（ODS）CLF-1样品。对样品进行不同制度的热处理,并进行了微观组织分析和力学性能测试。分析结果表明,经过正火和回火处理,ODS CLF-1组织为回火马氏体,当正火温度为1 100 ℃时晶粒尺寸最为均匀。回火温度对显微组织影响不明显,但回火温度升高,维氏硬度下降。热处理后样品中观察到明显的弥散分布的Y₂O₃颗粒和位错塞积,证实了弥散强化的作用。Y₂O₃颗粒尺寸不均匀,100 nm左右的大颗粒倾向于沿晶界分布,而较小的颗粒则在晶内分布。ODS CLF-1样品具有良好的高温拉伸性能,600 ℃时抗拉强度为370 MPa,延伸率为18.5%。屈服强度和抗拉强度随热处理温度的升高而降低。     

Oil palm empty fruit bunch (OPEFB) fiber reinforced PVC/ENR blend-electron beam irradiation

The effect of irradiation on the tensile properties of oil palm empty fruit bunch (OPEFB) fiber reinforced poly(vinyl chloride)/epoxidized natural rubber (PVC/ENR) blends were studied. The composites were prepared by mixing the fiber and the PVC/ENR blend using HAAKE Rheomixer at 150 °C. The composites were then irradiated by using a 3.0 MeV electron beam machine at doses ranging from 0 to 100 kGy in air and room temperature. The tensile strength, Young’s modulus, elongation at break and gel fraction of the composites were measured. Comparative studies were also made by using poly(methyl acrylate) grafted OPEFB fiber in the similar blend system. An increase in tensile strength, Young’s modulus and gel fraction, with a concurrent reduction in the elongation at break (Eb) of the PVC/ENR/OPEFB composites were observed upon electron beam irradiation. Studies revealed that grafting of the OPEFB fiber with methyl acrylate did not cause appreciable effect to the tensile properties and gel fraction of the composites upon irradiation. The morphology of fractured surfaces of the composites, examined by a scanning electron microscope showed an improvement in the adhesion between the fiber and the matrix was achieved upon grafting of the fiber with methyl acrylate.     

Improvement of carbon fiber surface properties using electron beam irradiation

Carbon fiber-reinforced advance composites have been used for structural applications,mainly on account of their mechanical properties.The main factor for a good mechanical performance of carbon fiber-reinforced com- posite is the interfacial interaction between its components,which are carbon fiber and polymeric matrix.The aim of this study is to improve the surface properties of the carbon fiber using ionizing radiation from an electron beam to obtain better adhesion properties in the resultant composite.EB radiation was applied on the carbon fiber itself before preparing test specimens for the mechanical tests.Experimental results showed that EB irradiation improved the ten- sile strength of carbon fiber samples.The maximum value in tensile strength was reached using doses of about 250 kGy.After breakage,the morphology aspect of the tensile specimens prepared with irradiated and non-irradiated car- bon fibers were evaluated.SEM micrographs showed modifications on the carbon fiber surface.     

N18锆合金的单轴拉伸和应力松弛性能

本工作试验研究20~700℃、不同应变加载速率下N18锆合金的单轴拉伸和应力松弛性能。结果表明,N18合金的单轴拉伸应力-应变曲线出现明显的屈服拐点,且温度低于500℃时呈现后继屈服强化,高于500℃后又呈后继屈服软化。除横向试样的断面收缩率高于轧向试样外,试样取向对N18合金的单轴性能影响不大。温度低于300℃时,N18合金的应变速率敏感性受温度的影响不大;350℃时,N18合金的敏感系数达到最小值,其后,对应变速率的敏感性随着温度的升高逐渐增强。N18合金在不同温度和应变水平下均产生明显的应力松弛。在300℃以内,最大应力松弛程度受温度影响较小,且随应变水平的增大明显降低;在350~550℃范围内,应变水平越高,对应的最大应力松弛程度越大;N18合金的最大松弛程度在350℃附近出现最小值。在350~450℃范围内,N18合金表现出明显的动态应变时效特性。     

低活化马氏体钢限制性模压织构演化行为及力学性能研究

利用低活化马氏体钢在500、600 ℃下进行了多道次限制性模压(CGP)实验,研究了不同温度下变形道次对其显微组织和力学性能的影响。结果表明：经3道次CGP变形后,低活化马氏体钢的平均晶粒尺寸从初始回火态的1.37 μm细化到0.88 μm;马氏体中形成了明显的（121）［012］、（011）［111］、（101）［111］织构,同时有（213）［111］织构出现,{112}{111}面织构的出现有效提升了材料的拉伸性能;铁素体中出现（012）［021］织构和明显的{013}〈113〉织构;抗拉强度与硬度显著上升,延伸率小幅降低。500 ℃下,抗拉强度经过1道次CGP变形后从初始态的586.31 MPa提升至693.01 MPa,3道次后又略下降至689.74 MPa;延伸率从初始态的18.59%降至12.13%。600 ℃下,抗拉强度经过1道次CGP变形后提升至685.97 MPa,3道次CGP变形后又略下降至679.30 MPa;延伸率降至15.62%。上述结果证明,CGP变形是提升低活化钢板力学性能的有效方法之一。     

Embrittlement of RAFM EUROFER97 by implanted hydrogen

About 380 μm thick specimens of low-activation martensitic stainless steel EUROFER97 were homogeneously implanted with protons below about 70 °C to concentrations up to about 1200 appm. Tensile tests were performed at 25 and 200 °C. The tests at 25 °C showed an increase of yield stress and ultimate tensile strength and a decrease of uniform elongation and elongation to fracture, while effects at 200 °C were strongly reduced. Scanning electron microscopy showed virtually no change of the ductile, transgranular fracture mode by the implanted H. A slight decrease of necking was observed only at the highest concentrations. The results are compared to previous measurements on F82H-mod and to literature results on tensile tests after He implantation and neutron irradiation. F82H-mod specimens were also implanted under applied tensile stress to concentrations up to 1900 appm. Straining was ascribed to accumulation of atomic defects, but no fracturing occurred. Thermal desorption measurements are included on H-implanted and tensile tested F82H-mod specimens. The results show significant data scatter, even within one specimen, with the highest measured values being in accordance with the implanted amount. In general, the H content is decreased after testing at higher temperatures, but even after testing at 350 °C, some specimens contain significant amounts.