Incident ion fluence gradients on the front and backside of flat samples

Plasma immersion ion implantation (PIII) is ideal for fast and efficient treatment into three-dimensional objects, as shown by experiments and simulations. In this presentation, a direct comparison of implantations into the front and backside of flat sample (disc, square and rectangle) at 5-15 kV pulse voltage with argon ions is performed with the spatial distribution of the incident ion fluence measured by spectroscopic ellipsometry on SiO₂/Si coupons. A strong influence of the supporting rod for the fluence distribution on the backside of the low symmetry samples, i.e. square and rectangle was observed, in contrast to no influence for the disc sample.     

On time-of-flight ion energy deposition into a metal target by high-intensity pulsed ion beam generated in bipolar-pulse mode

The energy deposition of high-intensity pulsed ion beam (HIPIB) into a titanium target was studied in TEMP-6 apparatus of bipolar-pulse mode using a self-magnetic field magnetically insulated ion diode (MID), where anode plasma was pre-generated by a first negative voltage and then mixed carbon ions and proton beam was extracted during the positive stage of the bipolar pulse. According with the time-of-flight (TOF) of ions, C⁺ arriving at the target 14 cm downstream from the MID was delayed by 55 ns relative to H⁺ at a peak accelerating voltage of 250 kV and the ion energy spectrum varied greatly, starting with a Gaussian profile at exit of MID and arriving with a multi-energy complex distribution. The TOF ion energy deposition of HIPIB showed that the energy deposition proceeded firstly in a deeper depth delivered by H⁺ and then moved towards a top layer dominated by C⁺. It is found that, the contribution of H⁺ to the energy deposition is negligible at the beam composition of 70%C⁺ and 30%H⁺. As a result, the gradient of energy deposition profile in target is negative by C⁺ deposition through the whole pulse. This unique feature of HIPIB energy deposition can lead to different thermal and dynamic effects as compared to previous studies of H⁺-abundant HIPIB, electron or laser beam, especially limiting subsurface heating that is concerned as a major cause of droplet ejection and surface cratering and waviness formation.     

脉冲离子束辐照致TiD_2膜力学性能的变化

金属氢化物(MH_x)应用于反应堆中子慢化剂、激光离子源片材料、中子发生器用靶时,会经历极端非平衡束流的辐照。本工作提出利用TEMP-6型强流脉冲离子束装置产生的强流脉冲离子束(high intensity pulsed ion beam,HIPIB)辐照Ti D_2膜,评估极端束流对膜力学性能的影响因素和影响程度。采用涂层附着力自动划痕仪、维氏显微硬度计对原始和辐照后的Ti D_2膜进行测试分析。研究结果发现:多次HIPIB的辐照效应导致膜面重熔再结晶,使其内部结构趋于更加致密化和平整化,能降低材料的摩擦系数并在一定程度上提高其初始临界载荷;D的释放有助于膜面韧性、显微硬度的提高,从而减轻了其塑性形变程度。     

Microstructure of pulsed laser deposited FePd thin films on amorphous and crystalline substrates

Equiatomic FePd thin films have been deposited at room temperature by pulsed laser deposition (PLD) on amorphous, Si₃N₄ and SiO₂, and crystalline, (100)-NaCl, substrates. The resulting FePd film microstructures have been characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). We observed a complex orientation relationship between grains in nanocrystalline thin films of FCC FePd and the single crystal NaCl substrates. FePd films obtained under identical deposition conditions using the amorphous substrates also exhibited nanocrystalline morphology but with a fiber texture and consisted of a phase mixture of FCC FePd and the tetragonal ordered L1₀-FePd phase.     

轰击能量对离子束辅助磁控溅射沉积Cr-N薄膜断裂韧性的影响

应用低能离子束辅助磁控溅射技术(IBAMS)沉积Cr-N薄膜,用场发射扫描电镜(FESEM)、原子力显微镜(AFM)和X射线衍射表征薄膜的组织结构,讨论了轰击能量对Cr-N薄膜组织、晶粒度以及硬度和断裂韧性的影响.结果表明:随离子束辅助轰击能量的升高,Cr-N薄膜由粗大的柱状晶变为细小的晶粒,当轰击能量达到1 200 V时,薄膜呈现等轴晶结构,薄膜致密度增加.FESEM得到的表面颗粒尺寸和AFM得到的粗糙度随轰击能量升高呈现相同的变化趋势,这些表观大颗粒是由许多小的亚晶块聚集而成.进一步用X射线衍射谱形分析表明:随轰击能量从0 V升高到800 V时,亚晶块的尺寸逐渐减小;到800 V时,晶块尺寸约为9 nm,但当能量升到1 200 V时,晶块尺寸反而增大,这是由离子束辅助轰击导致的两种不同机制而引起的,一种是离子轰击导致的喷丸碎化作用,而另一种为热效应引起的晶粒长大;当轰击能量从0 V增加800 V时,薄膜的硬度和断裂韧性都显著提高,与晶粒度的减小有关;而到1 200 V时,晶粒度较未辅助略大,但却具有很高的硬度以及较高的断裂韧性,说明硬度和断裂韧性的提高还与离子束轰击导致薄膜的致密化增加有关.     

用离子渗碳和离子渗氮的AISI 316L SS钢制备的扩张奥氏体在高温和高能脉冲离子束辐照下的稳定性

经离子渗碳或离子渗氮的奥氏体不锈钢制得扩张奥氏体。两种处理都得到过饱和氮或碳的fcc晶体结构,被高度硬化,能提高耐磨性,同时保持原有的耐腐蚀性。本项工作中研究了用离子渗碳或离子渗氮的含N和C的AISI 316L SS钢制备的扩张奥氏体,在高温(225~504℃)和具有高能(30~500 keV),高能量(~1015cm-2),短时间(~400 ns),轻离子束(氘和氦)的辐照下的稳定性。     

在高温和高能脉冲离子束辐射下离子渗碳和离子渗氮生成的扩张奥氏体的稳定性

奥氏体不锈钢用离子渗碳或离子渗氮能生成扩张的奥氏体。两种工艺得到的过饱和碳或氮的fcc晶体结构能很好地硬化,提高耐磨性,且保持原有的耐蚀性能。     

强流脉冲离子束辐照WC-Co硬质合金的组织与性能

用扫描电镜（SEM）、表面轮廓仪、X射线衍射仪（XRD）、电子探针（EPMA）和显微硬度计等方法,研究了强流脉冲离子束辐照WC-Co硬质合金的组织与性能。结果表明,HIPIB辐照使硬质合金表面发生快速重熔和Co粘结相的优先烧蚀,导致六方α-WC相向立方β-WC1-x相转变,形成丘状凸起重熔烧蚀形貌;硬质合金表面硬度随束流密度和辐照次数的增加先增加后减小,归因于辐照硬质合金表面重熔致密化、Co粘结相优先烧蚀、β-WC1-x相转变以及表面微裂纹的产生。     

Effect of high current pulsed electron beam treatment on surface microstructure and wear and corrosion resistance of an AZ91HP magnesium alloy

This paper reports an analysis of the microstructure and property modifications on a commercial Mg alloy AZ91HP treated by using High Current Pulsed Electron Beam (HCPEB). It is shown that, a thin layer consisting of nanograined MgO formed on the top surface after HCPEB (electron energy ∼ 30 keV, pulse duration 1 μs, energy density ∼ 3 J/cm²) treatment, below which is a melted layer with depth of about 8-10 μm. The heat affected zone (HAZ) underneath the melted layer and stress wave affected zone contains many stress induced deformation marks. Meantime, a nearly complete dissolution of the intermetallic phase Mg₁₇Al₁₂ in the melted layer is observed, leading to the formation of a super-saturated solid solution on the surface. This is due to the solute trapping effect occurred during the fast solidification process. As a result, the wear and corrosion resistance of the alloy were significantly improved as shown by sliding friction, wear and immersion tests.     

Electrochemical properties of microarc oxidation films on a magnesium alloy modified by high-intensity pulsed ion beam

Microarc oxidation (MAO) films on AZ31 magnesium alloy were treated by high-intensity pulsed ion beam (HIPIB) irradiation with ion energy of 300 keV at ion current density of 200 A/cm². A remelted layer of a few micrometers was produced on irradiated MAO films. The corrosion resistance of MAO films was characterized by potentiodynamic electrochemical test in 3.5% NaCl solution. The anodic polarization behavior of MAO samples exhibited a transition from the active anodic dissolution for the original one to the passivation-pitting breakdown for the modified films. The passivation-pitting breakdown voltage of modified films increased with multi-shot irradiation, i.e. from a value of − 1420 mV(SCE) at 1 shot to − 800 mV(SCE) at 5 shots, and the corresponding passivation current density decreased by two orders of magnitude. The irradiated MAO films have a higher corrosion potential than the original one, reaching a maximal value of − 1350 mV(SCE) at 5 shots from the original − 1580 mV(SCE). The electrochemical impedance spectrum (EIS) of modified MAO films was measured with varying the immersion time in 3.5% NaCl solution. The Nyquist impedance plots from modified films may show only a capacitive loop at the immersion time of 5 h, and the inductive loop occur at longer immersion time, whereas original films presenting both capacitive and inductive loops at all the immersion time. Bode plots of MAO films before and after irradiation were obviously distinguished in shape at low frequency range, especially at short immersion time. The evolution of Nyquist and Bode plots with immersion time was discussed in association with the processes of electrolyte penetration into the MAO structure and resultant reaction at the film-substrate interface. It is concluded that the improvement in the continuity and compaction of MAO films accounts for the enhanced corrosion resistance of the films irradiated by HIPIB.     

Effect of deposition temperature on structural, surface, optical and magnetic properties of pulsed laser deposited Al-doped CdO thin films

The objective of this work is to study the influence of deposition temperature on structural, surface, optical and magnetic properties of the Al doped CdO thin films prepared by pulsed laser deposition (PLD) technique. KrF excimer laser (λ = 248 nm, τ_l = 20 ns, ν = 10 Hz, ?_l = 2.5 J/cm²) was employed for the deposition of thin films. It is observed by XRD results that films grown at room temperature and 100 °C show preferential growth along (1 1 1) and (2 0 0) directions while high temperatures (200-400 °C) lead to preferential growth along the (2 0 0) direction only. The optical constants (n, k, α, and optical band gap energy) of films measured by spectroscopic ellipsometry show strong dependence upon deposition temperature. M-H loop of films, measured by vibrating sample magnetometer, deposited at 25 °C and 100 °C show paramagnetic nature while films deposited at temperatures (200-400 °C) exhibit ferromagnetic character. Scanning electron micrographs show degraded elongated grains at lower deposition temperatures, while smooth and compact surface is observed for films deposited at higher deposition temperatures.     

Effect of substrate bias voltage on the texture and microstructure of Cu thin films deposited by ion beam deposition

Cu thin films deposited by non-mass separated ion beam deposition under various substrate bias voltages were investigated. The film textures and microstructure were analyzed by X-ray diffraction and field emission scanning electron microscopy, and the resistivity of the film was measured with the Van der Pauw method. It was found that the optimum negative substrate bias voltage for Cu films was −50 V. The Cu films deposited without substrate bias voltage showed a columnar grain structure with small grains and random orientation. However, when a substrate bias voltage of −50 V was applied, the Cu films had a non-columnar structure with a strong (111) texture and large grains. The electrical resistivity of the Cu films decreased remarkably with increasing negative substrate bias voltage, and reaching a minimum value of 1.8±0.13 μΩ cm at the substrate bias voltage of −50V.     

强流脉冲离子束辐照镁合金微弧氧化膜的耐腐蚀性能

采用强流脉冲离子束在束流密度为200 A/cm2、辐照次数为1~10次条件下对AZ31镁合金微弧氧化膜进行辐照改性处理。采用扫描电子显微镜对氧化膜的表面及截面形貌进行表征;在Princeton Applied Research(PAR)2273型电化学工作站测量氧化膜的极化曲线。结果表明:在束流密度200 A/cm2、5次辐照条件下氧化膜表面获得连续、致密的改性层;以3.5%NaCl溶液为腐蚀液,氧化膜表面发生的腐蚀过程由辐照前的活化溶解向辐照后的钝化-孔蚀击穿转变;在束流密度200 A/cm2、5次辐照条件下击穿电位提高到最大值-800 mV(vs SCE)。强流脉冲离子束辐照产生的连续致密改性层是氧化膜耐蚀性改善的主要原因。     

Isothermal oxidation behaviour of a gradient NiCoCrAlSiY coating deposited by arc ion plating on a Ni-based single crystal superalloy

A gradient NiCoCrAlSiY coating consisting of Al-enriched outer zone and Cr-enriched internal zone was prepared using arc ion plating method and subsequent annealing treatment. Isothermal oxidations were performed at 1000 °C and 1100 °C in static air. The results confirmed an enhanced performance for the gradient NiCoCrAlSiY coating in contrast to the conventional NiCoCrAlSiY, due to the high-Al content and the in-situ Cr(Re, W)-rich diffusion barrier which exists in the gradient coating. The degradation mechanisms for the two coatings and the formation mechanism for the diffusion barrier are discussed.     

Electron beam deposited VC and NbC thin films on titanium: Hardness and energy-dispersive X-ray diffraction study

Films of VC and NbC of about 200 nm thickness were electron beam deposited on the sandblasted surface of metallic Ti substrates, preheated at 350 and 500 °C, to improve the surface hardness of Ti implants intended for application in orthopaedics. According to both standard angular-dispersive X-ray diffraction measurements and rocking curve analysis performed by energy-dispersive X-ray diffraction, the films were found to be textured preferentially along the (200) crystallographic direction. The (200)-oriented crystallites are randomly rotated around their growth axes, with no correlation among adjacent domains. The measured intrinsic hardness of the films is 24-25 GPa for VC and 18-21 GPa for NbC.     

Experimental study of electrochemical corrosion behaviour of bilayer on AZ31B Mg alloy

A bilayer on AZ31B magnesium alloy was prepared by first applying anodization to modify the substrate, and then depositing a self-assembled nanophase particle (SANP) film. Structure and corrosion behaviour are characterized by scanning electron microscopy, energy dispersion spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscope and electrochemical impedance spectroscopy. Experimental results indicate that the bilayer consists of a SNAP/loose layer and a dense layer, and provides the corrosion protection of Mg substrate for more than 354 h in 0.005 M NaCl solution. Therefore, the bilayer is effective to protect Mg alloy against corrosion for a long time.     

Effect of Y on the glass forming ability of the Fe–Nb system studied by ion beam mixing

Ion beam mixing experiments were carried out to investigate the effect of the Y addition on the glass forming ability and associated structural phase transformations of the Fe–Nb binary metal system. The results show that the addition of Y could extend the glass forming range of the Fe–Nb system from 25–75 at% Fe to 10–80 at% Fe, yet while the addition of Y exceeded 42 at%, the glass forming ability would be deteriorated. The effect of Y is considered to be attributed to the competition between the big size difference of the component metals and large positive heat of mixing of Y–Nb.     

W6Mo5Cr4V2钢表面强流脉冲离子束辐照研究

利用扫描电镜(SEM)、台阶仪、X射线衍射仪(XRD)、透射电镜(TEM)、显微硬度仪对W6Mo5Cr4V2钢经强流脉冲离子束(HIPIB)辐照前后试样的表面形貌、粗糙度、表层的组织结构及硬度进行了分析,探讨了"熔坑"和硬度"多峰"态形成的原因.结果表明,试样表面粗糙度随辐照次数的增加有所减小;辐照过程使该钢体心立方的马氏体α'-Fe向面心立方的奥氏体γ-Fe转变,碳化物溶解,马氏体溶碳量增大且晶粒细化,点阵畸变度增大,使W6Mo5Cr4V2钢表面硬度有较大的提高.     

X-ray photoelectron spectroscopy analysis of zirconium nitride-like films prepared on Si(100) substrates by ion beam assisted deposition

Thin zirconium nitride films were prepared on Si(100) substrates at room temperature by ion beam assisted deposition with a 2 keV nitrogen ion beam. Arrival rate ratios ARR(N/Zr) used were 0.19, 0.39, 0.92, and 1.86. The chemical composition and bonding structure of the films were analyzed with X-ray photoelectron spectroscopy (XPS). Deconvolution results for Zr 3d, Zr 3p_3/2, N 1s, O 1s, and C 1s XPS spectra indicated self-consistently the presence of metal Zr⁰, nitride ZrN, oxide ZrO₂, oxynitride Zr₂N₂O, and carbide ZrC phases, and the amounts of these compounds were influenced by ARR(N/Zr). The chemical composition ratio N/Zr in the film increased with increasing ARR(N/Zr) until ARR(N/Zr) reached 0.92, reflecting the high reactivity of nitrogen in the ion beam, and stayed almost constant for ARR(N/Zr) ≥ 1, the excess nitrogen being rejected from the growing film. A considerable incorporation of contaminant oxygen and carbon into the depositing film was attributed to the getter effect of zirconium.     

液压机横梁弯曲及模座裂纹的数值模拟研究

针对载货车纵梁使用50 000 k N10缸联动的液压机设备冲压成形,设备横梁在生产中产生了弯曲,纵梁成形模的上模座加强筋部位也出现了裂纹,建立了整个工作部分的有限元模型,分析了上述2种现象产生的原因,由于纵梁长度存在差异,使用的液压缸数量不同容易使设备产生偏压,造成横梁产生弯曲,并使无纵梁板料位置处的模座加强筋产生较大应力。