单晶YSZ的Xe+离子辐照效应研究

 200keV Xe⁺离子辐照使单晶YSZ由无色透明变成紫色透明，结果表明，能量为200keV，注量为1×10¹⁷cm^-22的Xe⁺离子辐照YSZ单晶产生的损伤高达350dpa，在损伤区产生高密度的缺陷，但仍然没有发生非晶化转变。吸收光谱测试结果表明，产生吸收带的注量阈值大约为10¹⁶cm^-2。注量为1×10¹⁶cm^-2和1×10¹⁷cm^-2的样品，吸收带峰值分别位于522nm和497nm。光吸收带可能与Zr阳离子最近邻的氧空位捕获电子形成的F型色心和Y阳离子近邻的氧离子捕获空穴形成的V型色心有关。     

310 ℃和350 ℃下锆-4合金中沉淀相非晶化研究

用大束流加速器和透射电子显微镜研究了Zr-4合金在310 ℃和350 ℃下的质子辐照效应。当质子能量为2 MeV，在310 ℃和350 ℃下质子辐照产生原子离位损伤达5 dpa（注量率为8.5×1013 cm-2·s-1），辐照前后的明场像、高分辨相和电子衍射花样均表明:在310 ℃辐照产生原子损伤达到5 dpa，沉淀相Zr(Cr,Fe)2边缘5～10 nm的区域已经非晶化，而在350 ℃时质子辐照却没有非晶化发生。沉淀相Zr(Cr,Fe)2的元素分布图像和浓度分布表明，铁元素向基体扩散并且聚集在非晶化边界区域。     

退火对He注入及随后208Pb27+辐照的Al2O3单晶PL谱的影响

利用高能离子研究了110 keV 的He⁺注入Al₂O₃单晶及随后230 MeV的²⁰⁸Pb²⁷⁺辐照并在不同温度条件下退火样品的光致发光的特性. 从测试结果可以清楚地看到在375 nm，390 nm，413 nm 和450 nm 出现了强烈的发光峰. 经过600 K退火2 h后测试结果显示，390 nm发光峰增强剧烈，而别的发光峰显示不明显. 在900 K退火条件下，390 nm的发光峰开始减弱相反在510 nm出现了较强的发光峰，到1100 K退火完毕后390 nm的发光峰完全消失，而510 nm的发光峰相对增强. 从辐照样品的FTIR谱中看到，波数在460—510 cm^-1间的吸收是振动模式，经过离子辐照后，吸收带展宽，随着辐照量的增大，Al₂O₃振动吸收峰消失，说明Al₂O₃振动模式被完全破坏. 1000—1300 cm^-1之间为Al-O-Al桥氧的伸缩振动模式，辐照后吸收带向高波数方向移动. 退火后的FTIR谱变化不大.     

采用EPR谱和TEM对YSZ单晶辐照损伤的研究

 利用电子顺磁共振(EPR)谱和透射电子显微镜(TEM)研究了YSZ单晶的辐照效应。200 keV的Xe和400 keV的Cs离子注入［111］取向的YSZ单晶中，注量均为5×10¹⁶ cm^-2。EPR结果表明辐照产生了共振吸收位置g‖=1.989 和 g⊥=1.869、对称轴为［111］的六配位Zr³⁺顺磁缺陷。Cs辐照产生了比Xe 离子辐照多约150倍的六配位Zr³⁺顺磁缺陷。两种样品的剖面电子显微分析表明没有发现非晶化转变，但是Cs离子辐照的样品在损伤集中区域产生了密度较高的缺陷。因此，EPR谱和电子显微观察均说明在相同离位损伤(约160 dpa)的情况下，Cs离子辐照比Xe 离子辐照产生了更多的缺陷。造成这一现象的原因是Cs离子是化学活性的而Xe 离子却是惰性的。     

单晶YSZ的Xe+辐照损伤的电子显微分析

 不同注量200keV Xe⁺ 注入YSZ单晶样品的电子显微分析结果表明，随着辐照注量的增加，缺陷簇的密度增大，在1×10¹⁵~1×10¹⁶cm^-2Xe⁺注量，缺陷簇密度迅速增大，形成间隙型位错环；当Xe⁺注量增大到1×10¹⁷cm^-2，缺陷簇密度的增加变得缓慢，并且有直径为2～4nm的Xe气泡析出。选区电子衍射花样表明YSZ样品没有产生非晶化转变。在Xe⁺辐照的离位率高达约350dpa的情况下，YSZ晶体没有非晶化，其原因主要是由于注入的Xe⁺以气泡形式析出。     

Ti-2Al-2.5Zr合金He离子辐照效应研究

 在Ti-2Al-2.5Zr合金中注入能量为75 keV的He离子，注入剂量分别为5×10¹⁶cm^-2，1×10¹⁷ cm^-2。通过显微硬度测量和剖面电子显微观察，研究了He离子对Ti-2Al-2.5Zr合金力学性能和显微组织的影响。结果表明:样品的显微硬度随He离子注量的增加而升高，在温度为350和550 ℃的Ar气中退火后硬度有所下降。剖面电子显微观察发现有位错环和He气泡生成，退火后He气泡有长大、缺陷有回复的趋势。辐照产生的位错环是辐照后硬度升高的直接原因，其退火发生回复又引起硬度随退火温度的升高而降低。     

高剂量Ar离子辐照Si缺陷产生及其退火行为EPR研究

112MeVAr离子在50K以下的低温辐照Si到8×10¹⁴/cm²剂量,室温下采用电子顺磁共振技术分析了由辐照引起的缺陷产生及其退火行为,结果表明:Ar离子辐照在Si中引起了中性四空位(Si-P3心)､带正电荷的〈100〉劈裂的双间隙子(Si-P6心)以及连续的非晶层3种缺陷的形成. 在200℃的退火温度,Si-P3心和Si-P6心消失,这时带负电荷的五空位(Si-P1心)开始生长,Si-P1心可以保持到550℃左右的退火温度. 在350℃时,可以明显地观测到另一个含有更多空位的顺磁缺陷心(Si-A11心).连续非晶层的再结晶需要600℃以上的温度,并且在整个退火过程中,非晶顺磁共振线的线型和线宽保持不变. 定性地讨论了结果.     

电子束在VO2薄膜中引起的价态、相结构和光学性能的改变

 利用能量为1.7MeV, 注量分别为1.25×10¹³/cm², 1.25×10¹⁴/cm², 1.25×10¹⁵/cm²的电子束辐照VO₂薄膜,采用XPS, XRD等测试手段对电子辐照前后的样品进行分析,并研究了电子辐照对样品相变过程中光透射特性的影响。结果表明电子辐照引起VO₂薄膜中V离子出现价态变化现象,并使薄膜的X射线衍射峰发生变化。电子辐照在样品中产生的这些变化显著改变了VO₂薄膜的热致相变光学特性。     

Ar离子辐照非晶态合金引起的尺寸变化

利用兰州重离子加速器(HIRFL)提供的2.79MeV/u Ar离子,在50K以下的低温辐照了Fe₄₇Ni₂₉V₂Si₆B₁₆等4种非晶态合金样品,室温下使用光学显微镜对辐照前、后的同一样品拍照,对比测量了样品的宏观尺寸. 结果表明:在辐照剂量为1.5×10¹⁴离子/cm²时,非晶态合金形变不明显,测量到的样品宽度相对增长Δb/b₀均小于1.0%;当辐照剂量增加到1.6×10¹⁵离子/cm²时,所有非晶态合金样品都发生了显著的形变,其宽度相对增长分布在4.3%—12.0%之间,对此结果进行了定性的分析.     

18 MeV质子辐照对TiNi形状记忆合金R相变的影响

 研究了用HZ-B串列加速器的18MeV质子辐照对TiNi形状记忆合金R相变的影响，辐照在奥氏体母相状态下进行。示差扫描量热法（DSC）表明，辐照后R相变开始温度T^s_R和逆马氏体相变结束温度T^f_A随辐照注量的增加而降低。当注量为1.53×10¹⁴/cm²时，T^sR和T^f_A分别下降6K和13K，辐照未引起R相变结束温度T^s_R和逆马氏体相变开始温度T^f_A的变化。表明辐照后母相(奥氏体相)稳定。透射电镜（TEM）分析表明辐照后没有引起合金可观察的微观组织变化。辐照对R相变开始温度T^s_{R和逆马氏体相变结束温度Af的影响可能是由于质子辐照后产生了孤立的缺陷团，形成了局部应力场，引起晶格有序度的下降所造成的。}     

Microstructure evolution of zircaloy-4 during Ne ion irradiation and annealing: An in situ TEM investigation

The microstructural evolution of zircaloy-4 was studied, including the amorphization and recrystallization of Zr（Fe, Cr）2 precipitates, and the density of dislocations under in situ Ne ion irradiation and post annealing. The results show that irradiation at a relatively high temperature and dose induces the formation of nanocrystals in pre-amorphized Zr（Fe, Cr）2 precipitates. The recrystallized nanocrystals also have the structure of hcp-Zr（Fe, Cr）2. The formation of the nanocrystals is thought to be the consequence of competition between atomistic disordering and the recrystallization of precipitates under ion irradiation. The free energy of the nanocrystal is lower than that of the amorphous state, which is another reason for the recrystallization of the precipitates. With increased annealing temperature, the density of the nanocrystals is increased. The dislocation density sharply decreases with the increase in the annealing temperature, and its size increases.     

Effect of simultaneous helium implantation on the microstructure evolution of Inconel X-750 superalloy during dual-beam irradiation

This study focuses on investigation into the effect of helium implantation on microstructure evolution in Inconel X-750 superalloy during dual-beam (Ni⁺/He⁺) irradiation. The 1 MeV Ni⁺ ions with the damage rate of 10^?3 dpa/s as well as 15 keV He⁺ ions using rate of 200 appm/dpa were simultaneously employed to irradiate specimens at 400 °C to different doses. Microstructure characterization has been conducted using high-resolution analytical transmission electron microscopy (TEM). The TEM results show that simultaneous helium injection has significant influence on irradiation-induced microstructural changes. The disordering of γ′ (Ni₃ (Al, Ti)) precipitates shows noticeable delay in dose level compared to mono heavy ion irradiation, which is attributed to the effect of helium on promoting the dynamic reordering process. In contrast to previous studies on single-beam ion irradiation, in which no cavities were reported even at high doses, very small (2–5 nm) cavities were detected after irradiation to 5 dpa, which proved that helium plays crucial role in cavity formation. TEM characterization also indicates that the helium implantation affects the development of dislocation loops during irradiation. Large 1/3 〈1?1?1〉 Frank loops in the size of 10–20 nm developed during irradiation at 400 °C, whereas similar big loops detected at higher irradiation temperature (500 °C) during sole ion irradiation. This implies that the effect of helium on trapping the vacancies can help to develop the interstitial Frank loops at lower irradiation temperatures.     

The feasibility of Al-based oxide precipitation in Fe–10%Cr alloy by ion implantation

This paper reports the feasibility of nano-oxide precipitate formation in Fe–Cr alloy by ion implantation synthesis. High contents of Al⁺ and O⁺ ions were implanted into thin films of high purity Fe–10%Cr alloy at room temperature and were studied by transmission electron microscopy (TEM) and atom probe tomography (APT). In contrast, to the common two-stage implantation/annealing scheme of precipitate ensemble synthesis by ion beams, cluster formation took place at the implantation stage in our study, requiring no subsequent high-temperature annealing. The post-implantation microstructural examination revealed in the as-implanted thin foil an array of precipitates with diameters in the range of 3–30?nm. The precipitate number density distribution was found to depend on the foil thickness. The precipitate enrichment with both Al and O was confirmed by the energy-filtered TEM analysis. Judging from the electron diffraction pattern and high-resolution TEM analysis, the crystal lattice of precipitates corresponds to some cubic modification of aluminium-rich oxide or pure aluminium oxide. The precipitate lattice alignment with the host matrix was revealed for at least a part of precipitates. The analysis of APT data using cluster detection algorithm indicates the presence of local zones enriched in Al and O, even in those areas of as-implanted samples where no clusters were visible by TEM.     

铝中气泡在电子束辐照下的异常放热现象

在室温下,利用离子加速器对纯铝透射样品分别注入He⁺,Ne⁺和Ar⁺三种惰性气体离子,通过透射电子显微镜原位观察分析了纯铝中三种气体气泡在电子束辐照下形貌及电子衍射花样的变化.实验表明,在200 keV电子束辐照下,三种惰性气体气泡均会合并长大,亮度逐渐增强,最终破裂,气泡内部产生许多约几个纳米的黑色斑点衬度像,选区电子衍射花样由单晶斑点衍射花样变为多晶衍射环.这一现象的原因可能是气泡在电子束辐照过程中发生了放热反应,使气泡附近铝熔化后再结晶产生多晶,从而在电子衍射花样中观察到了多晶衍射环.然而,氦气泡在80 keV电子束辐照下氦气泡形貌和选区电子衍射花样保持不变,辐照后衍射花样中无多晶衍射环产生;氦氩混合气体气泡在200 keV电子束辐照下气泡形貌和选区电子衍射花样同样保持不变;这可能与电子束能量和气泡内气体压力有关.     

Effect of helium concentration on irradiation damage of Fe-ion irradiated SIMP steel at 300℃ and 450℃

SIMP steel is newly developed fully martensitic steel for lead-cooled fast reactors and accelerator-driven systems.It is important to evaluate its radiation resistance via high flux neutron irradiation, where dense He atoms can be formed via(n, α) transmutation reaction. Co-irradiation with Fe and He ions, instead of neutron, was performed. Specimens were irradiated with 6.4-Me V Fe ions to the damage dose of 5 dpa at a depth of 600 nm. Three different helium injection ratios of 60-appm He/dpa(dpa: displacements per atom), 200-appm He/dpa and 600-appm He/dpa at a depth of 600 nm,were performed. Two different irradiation temperatures of 300℃ and 450℃ were carried out. The effect of helium concentration on the microstructure of Fe-irradiated SIMP steel was investigated. Microstructural damage was observed using transmission electron microscopy. The formed dislocation loops and bubbles depended on the helium injection ratio and irradiation temperature. Lots of dislocation loops and helium bubbles were homogeneously distributed at 300℃, but not at 450℃. The causes of observed effects are discussed.     

离子注入/辐照引起Al2O3单晶的改性研究

600K温度下用110keV的He^＋,Ne^＋,Ar^＋离子注入及320K温度下用230MeV的^208Pb^27＋辐照Al2O3单晶样品,研究了离子注入和辐照对Al2O3单晶样品结构和光学特性的影响。从测得的光致发光谱可以清楚地看到,所有样品在波长为375,413和450nm处出现了强的发光峰。且所有5×10^16ion／cm^2注入样品的发光峰均最强。经过高能Pb辐照后的样品,在390nm处出现了新的发光峰。透射电镜分析发现在注入氖样品100nm入射深度以内形成了高浓度的小空洞（1-2nm）,在Ne沉积区域有少量大空洞形成。傅立叶变换红外光谱分析发现,波数在460-510cm^-1间的振动吸收带经过离子辐照后展宽,随着辐照量的增大,该振动吸收强度显著减弱。1000—1300cm^-1对应Al-O-Al桥氧伸缩振动模式的吸收带,辐照后向高波数方向移动。对离子注入和辐照对Al2O3单晶样品结构损伤机理进行了初步探讨。Single crystal sapphire （Al2O3 ） samples were implanted at 600 K by He, Ne and Ar ions with energy of 110 keV to doses ranging from 5 × 10^16 to 2× 10^17 ion/cm^2 or irradiated at 320 K by ^208Pb^27＋ ion with energy of 1.1 MeV/u to the fluences ranging from 1 × 10^12 to 5 × 10^14 ion/cm^2. The modification of structure and optical properties induced by ion implantation or irradiation were analyzed by using photoluminescence（PL） and Fourier transformation infrared spectrum（FIR） spectra and transmission electron microscopy（ TEM ） measurements. The PL measurements showed that absorption peaks located at 375,413 and 450 nm appeared in all the implanted or irradiated samples, the PL intensities reached up to the maximum for the 5 × 10^16 ion/cm^2 implanted samples. After Pb-ion irradiation, a new peak located at 390 nm formed. TEM analyses showed that small size voids,（ 1--2 nm） with high density were formed in the region from the surface till to about 100 nm in depth and also large size Nebubble formed in the Ne-doped region. From the obtained FTIR spectra, it was found that Pb-ion irradiation induced broadening of the absorption band in 460-510 cm^-1 and position shift of the absorption band in 1 000- 1 300 cm^- 1 towards to high wavenumber. The possible damage mechanism in single crystal sapphire induced by energetic ion implantation or irradiation was briefly discussed.     

Ne离子束辐照引起Gd2Ti2O7烧绿石体积肿胀效应研究

在液氮低温下用400 keV的Ne2+离子束对Gd₂Ti₂O₇多晶烧绿石进行了辐照实验研究, 离子束辐照量范围为5×1014—1×1016ions/cm2。利用掠X射线衍射技术对样品辐照层的结构变化进行了分析表征, X射线的掠射角分别为γ=0.25°, 0.5°, 1°和3°。结果表明: 在该实验条件的离子束辐照下, Gd₂Ti₂O₇辐照层会发生明显的体积肿胀效应, 体积肿胀程度随入射离子束辐照量的增大而增大; 在同一辐照量下, 辐照层的体积肿胀程度也随X射线入射角的增大而增大。当辐照量达到1×1016ions/cm2时, 辐照层发生非晶化相变。Polycrystalline pyrochlore Gd₂Ti₂O₇ compounds were irradiated with 400 keV Ne2+ ions at cryogenic temperature (~77 K). The irradiation fluences was ranging from 5×1014 to 1×1016 ions/cm2, corresponding to a peak ballistic damage dose of ~0.16 to 3.3 displacements per atom . Irradiation\|induced structural evolution was examined using grazing incidence X\|ray diffraction (GIXRD) at angles from 0.25° to 3° degrees. It was found that the lattice parameter increases as a function of (1) X\|ray incident angle and (2) ion irradiation fluence, suggesting that the irradiated layer is volumetrically swelled compared with the underlying un\|irradiated substrate. At ion fluence of 1×1016 ions/cm2, the irradiation layer was found to be amorphous.