脉冲Ti＋C双重离子注入抗磨损优化结构的研究

大剂量Ｔｉ＋、Ｃ＋和Ｔｉ＋＋Ｃ＋注入Ｈ１３钢可使注入层硬度和抗磨损寿命明显增加，尤以Ｔｉ＋＋Ｃ＋双注入效果最佳．实验结果表明注入的Ｔｉ和Ｃ原子浓度可分别达到２２％和４５％；超饱和Ｔｉ和Ｃ浓度形成了固溶强化；注入层中已形成弥散的硬化相，如Ｆｅ２Ｔｉ、ＴｉＣ、Ｆｅ２Ｃ和Ｆｅ５Ｃ２等，出现了弥散强化效果．注入层表面形成了一层２０ｎｍ厚的薄碳层，使之呈现出自滑润特性。     

离子注入对超高分子聚乙烯磨损性能的影响

用８０ｋｅＶ不同剂量的Ｃ３Ｈ＾＋８,Ｎ＾＋２对超高分子聚乙烯样品进行离子注入,通过反冲探测分析表明注入层Ｈ含量的变化,对样品表面在离子注入前后的磨损性能进行了测试。实验结果显示,离子注入以后样品表面氢含量减少,磨损性能增强。     

C+W+C离子注入H13钢复合钝化层的抗腐蚀特性

用多次扫描电位法研究了C＋W＋C离子注入H13钢的结构和相变及其对抗腐蚀特性的影响,研究了抗腐蚀相生成的条件以及这些相对抗腐蚀特性的作用,并对其改性机理进行了讨论。实验结果表明,W离子和C离子多重离子注入H13钢可在注入层中形成超饱和浓度的W和C原子分布,分布形状为类高斯分布;并可在注入层中形成钨的碳化物WC和W2C相、合金相Fe2W和Fe6W6C等,这些弥散相不但可以使注入层强化,而且也可使表面钝化,从而增强了表面抗腐蚀特性;W和C双重离子注入具有W和C单离子注入的特性,可进一步提高H13钢的抗腐蚀特性,随着W重离子和C重离子注入剂量的增加,抗腐蚀特性进一步增强。样品C3W3C3的Jp经50个周期腐蚀后,其值比H13钢的Jp下降了60％,而C3W3的Jp比H13钢的Jp下降了47％。C3W3C3的Jp比C3W3的Jp小34％。扫描电子显微镜观察表明,腐蚀后抗腐蚀的钝化层依然存在。     

硅离子注入聚合物摩擦特性研究

采用金属蒸汽真空弧（MEVVA）离子注入机引出的Si离子进行了聚酯薄膜（PET）改性研究，注入后的聚酯膜表面结构发生了很大的变化。用透射电子显微镜观察了注入聚酯膜的横截面，结果表明，在注入层形成颗粒的沉积。红外吸收测量揭示这些颗粒为SiC和富集的碳颗粒。这些颗粒增强了注入层表面强化效果。用纳米硬度计测量显示，Si离子注入可明显地提高聚酯膜表面硬度和杨氏模量，从而极大地的增强了表面抗磨损特性。最后讨论了Si离子注入聚酯膜改善特性的机理。     

高能离子注入对聚酚亚胺薄膜硬度的影响

报道了聚酚亚胺薄膜在高能（６５０ｋｅＶ－２ＭｅＶ）Ｂ＋、Ｃ＋和Ｃｕ＋离子注入后硬度的变化。对注入样品进行了显微硬度测量和ＸＰＳ及ＲＢＳ分析，观察了硬度与离子种类、能量及注入剂量的依赖关系。结果表明，离子注入之后薄膜样品的显微硬度值明显提高，注入离子在样品中的电子能量损失对聚合物材料改性起着关键作用。ＸＰＳ和ＲＢＳ分析显示，离子注入之后聚酰亚胺薄膜中Ｃ的含量增加，形成了以苯环结构为主的新的交联网状结构。     

高能离子注入对聚酰亚胺薄膜硬度的影响

报道了聚酰亚胺薄膜在高能（６５０ｋｅＶ－２ＭｅＶ）Ｂ＾＋、Ｃ＾＋和Ｃｕ＾＋离子注入后硬度的变化。对注入样品进行了显微硬度测量和ＸＰＳ及ＲＢＳ分析，观察了硬度与离子种类、能量及注入剂量的依赖关系。结果表明，离子注入之后薄膜样品的显微硬度值明显提高，注入离子在样品中的电子能量损失对聚合物材料改性起着关键作用。ＸＰＳ和ＲＢＳ分析显示，离子注入之后聚酰亚胺薄膜中Ｃ的含量增加，形成了以苯环结构为主的新的交联     

Zr—4合金中第二相Zr（Fe,Cr）2的电化学分离

通过测定Ｚｒ－４合金和Ｚｒ（Ｆｅ，Ｃｒ）２合金在各种电解液中的阳极极化行为，和对阳极产物的电子显微镜和Ｘ射线衍射分析，得到了一种适合分离Ｚｒ－４合金中第二相Ｚｒ（Ｆｅ，Ｃｒ）２的电解液：乙醇：正丁醇：高氯酸＝２５：３：２；室温条件下，控制电位为－０．４５～－０．８０Ｖ（ＳＣＥ）。     

Zr－4合金中第二相Zr（Fe，Cr）_2的电化学分离

通过测定Ｚｒ－４合金和Ｚｒ（Ｆｅ，Ｃｒ）２：合金在各种电解液中的阳极极化行为，和对阳极产物的电子显微镜和Ｘ射线衍射分析，得到了一种适合分离Ｚｒ－４合金中第二相Ｚｒ（Ｆｅ，Ｃｒ）２的电解液：乙醇：正丁醇：高氯酸＝２５：３：２；室温条件下，控制电位为－０．４５￣－０．８０Ｖ（ＳＣＥ）．     

高能Ti离子注入H13钢强化机理研究

对高能Ti离子注入H13钢的强化机理进行了详细的研究。利用离子注入精确可控,掺杂不受固溶度和材料温度限制的特点,详细研究了H13钢中离子注入各种强化机理的作用。结果证明,用离子注入可将几种强化效果同时用于H13钢强化,从而得到最佳的强化效果。低温、大注入量注入下,以位错强化、超饱和固溶强化为主,可使注入层强化效果提高。400℃加温下注入由于Fe_2Ti和TiC硬化弥散相的形成,强化效果进一步提高。硬度可提高3.2倍。抗磨损效果可提高11倍。注入样品退火可改善弥散强化的效果。     

Ar离子辐照的非晶态合金表面发泡扫描电镜观测

１５０、１９５和３００ｋｅＶＡｒ离子在室温下辐照非晶态合金Ｃｏ７０．２Ｆｅ３． ９Ｎｄ３．９Ｓｉ１４Ｂ８和Ｃｏ６６Ｆｅ４．５Ｖ２．２５Ｎｉ２．２５Ｓｉ１０Ｂ１５，扫描电镜在一定的辐照剂量范围观测到了表面发泡形成，发泡形成的临界剂量和直径随离能量增加而增加。Ａｒ离子能量高于１９５ｋｅＶ时，发泡和发泡破裂是主要的表面损伤现象，而在１５０ｋｅＶＡｒ离子辐照下，未观测到发泡破裂。     

Ti、C和Ti+C离子注入钢表面纳米相镶嵌复合层的形成

选取质量差异很大的Ｃ、Ｔｉ、Ｔｉ＋Ｃ离子对钢进行了离子注入,用透射电子显微镜对注入样口横截面进行结构分析。结果表明,注入层结构发生了明显的变化,形成了纳米相镶嵌复合层,复合层的深度大约是相应离子射程的５．９－１３．７８倍。三条条件下注入,其结构变化有明显的差异。用ＴＲＩＭ９５程序对三种离子注入的碰撞参数进行了计算,结果表明,结构的变化明显地与注入参数相关,最后分子复合层特性的变化与注入条件和结构变     

Effect of Fe content on positron annihilation in neutron irradiated VFe alloys

Neutron irradiated VxFe alloys (with x from 0 to 5 at.%) have been studied by the conventional positron annihilation technique. A remarkable narrowing of angular correlation of annihilation radiation (ACAR) curves was observed for all alloys investigated. A specific feature of ACAR curves in pure vanadium is the presence of a narrow component attributed usually to the positronium (Ps) formation in voids, with inner surfaces covered by gaseous impurities such as oxygen. Significant changes in the ACAR curve component intensities with increase of iron content has been observed. At Fe concentration of about 1 at.% the narrow component disappears completely and the intensity of the middle one decreases significantly. It was concluded that the increase of Fe concentration in VFe alloys suppresses the void surface contamination by oxygen atoms and changes the positron work function from bulk materials into voids. Such behavior of the ACAR curve component intensities can be explained in terms of radiation-induced segregation of iron atoms at point defect sinks.     

C276合金高温拉伸强度的显微分析

C276合金具有优异的高温拉伸强度。为研究C276的高温强化机制,利用光学显微镜（OM）、扫描电镜（SEM）和X射线衍射（XRD）方法,分析C276在500~650℃下拉伸断裂的试样。结果表明：C276在500~650℃下拉伸时,随晶粒尺寸的增大,屈服强度先增加后减小,两者不符合Hall-Petch关系。在晶体内观察到了形变孪晶,未发现沉淀相析出。因此,C276在高温下仍是以固溶强化为主,可能兼有孪晶强化,而无细晶强化和沉淀强化的效果。     

Microstructural characterization of U-7Mo/Al-Si alloy matrix dispersion fuel plates fabricated at 500 °C

The starting microstructure of a dispersion fuel plate will impact the overall performance of the plate during irradiation. To improve the understanding of the as-fabricated microstructures of U-Mo dispersion fuel plates, particularly the interaction layers that can form between the fuel particles and the matrix, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analyses have been performed on samples from depleted U-7Mo (U-7Mo) dispersion fuel plates with either Al-2 wt.% Si(Al-2Si) or AA4043 alloy matrix. It was observed that in the thick interaction layers, U(Al, Si)3 and U6Mo4Al43 were present, and in the thin interaction layers, (U, Mo) (Al, Si)3, U(Al, Si)4, U3Si3Al2, U3Si5, and possibly USi-type phases were observed. The U3Si3Al2 phase contained some Mo. Based on the results of this investigation, the time that a dispersion fuel plate is exposed to a relatively high temperature during fabrication will impact the nature of the interaction layers around the fuel particles. Uniformly thin, Si-rich layers will develop around the U-7Mo particles for shorter exposure times, and thicker, Si-depleted layers will develop for the longer exposure times.     

The development of validation methodology of multi-axial creep damage constitutive equations and its application to 0.5Cr0.5Mo0.25V ferritic steel at 590 °C

Research progress on the development of validation methodology for multi-axial creep damage constitutive equations and its specific application to 0.5Cr0.5Mo0.25V ferritic steel at 590 °C is presented. A set of new phenomenological multi-axial creep damage constitutive equations was proposed aiming at overcoming the deficiency of inconsistency between predicted rupture strains and observed ones. Based on these explicit consistent requirements, an improved validation methodology is proposed and applied to 0.5Cr0.5Mo0.25V ferritic steel at 590 °C. It shows that the predictions of this new set of constitutive equations are consistent with experimental observations. It also reveals a significant difference in creep curves between different sets of constitutive equations and the need for experimental data so that the coupling of damage and creep deformation can be further examined.     

Cu离子和Al离子注入M2钢表面改性研究

报道了M2型高速工具钢在Cu,Al离子注入后表面硬度及抗磨损性的变化。对注入样品进行了显微硬度及抗磨损性的测量和XRD与RBS分析,观察了表面强化与离子注入条件之间的关系。结果显示,注入样品与未注入样品相比,表面硬度及抗磨损性均有显著提高。分析结果表明,Cu,Al离子注入后样品中产生了不同的相,它们对表面强化所起的作用不同。     

Influence of oxide structure on the elevated temperature pitting behaviour of Fe-Cr-Ni alloys

The influence of temperature, potential, alloy and electrolyte composition on the growth of hot water oxide layers on stainless steel type AISI 321 and Fe-Cr-model alloys is presented. The correlation between the oxide layer properties and the pitting corrosion behaviour is discussed. In situ electrochemical investigations have been carried out in aqueous electrolytes (pH 8) on hydrothermal conditions varying from 150 to 250°C. After hot water exposition the steel surfaces were examined microscopically. The porosity of these layers increases with rising temperature due to a change in crystallinity from a fine-crystalline to a coarse-crystalline structure. It is shown that the pitting initiation mechanism is strongly dependent on the morphology of the oxide layers. At 150°C pitting corrosion occurs, whereas at 250°C the formation of extended hollow shaped corrosion has been observed. The cause of the detected inhibiting effect of sulphate ions on the chloride induced pitting is discussed. Furthermore, evident dependencies of the pitting susceptibility on the chromium content of the alloy and on the oxide layer preformation potential have been observed.