轧制对Zr60Al15Ni25块体非晶合金晶化动力学的影响

通过线性DSC实验研究了轧制对Zr60Al15Ni25大块非晶合金晶化动力学的影响。实验结果表明,Zr60Al15Ni25非晶合金在轧制塑性变形过程中,随着变形量的增加,热稳定性降低。Zr60Al15Ni25块体非晶合金轧制后原子组态的变化主要影响晶化的形核阶段,变形量较低时(20%)合金原子组态向无序方向发展,导致晶化速率变慢,晶化变得比较困难。随着轧制的进一步增加,合金原子的无序性降低,晶化速率又逐渐提高,从而使其在随后加热过程中的晶化变得比较容易。     

Understanding atomic-scale phase separation of liquid Fe-Cu alloy

Using liquid Fe 60 Cu 40 alloy as a model, the structure of liquid Fe-Cu alloy systems is investigated in the temperature range 1200 2200 K, covering a large metastable undercooled regime, to understand the phase separation of liquid Fe-Cu alloys on the atomic scale. The total pair distribution functions (PDFs) indicate that liquid Fe 60 Cu 40 alloy is ordered in the short range and disordered in the long range. If the atom types are ignored, the total atom number densities and PDFs demonstrate that the atoms are distributed homogenously in the liquid alloy. However, the segregation of Fe and Cu atoms is very obvious with decreasing temperature. The partial PDFs and coordination numbers show that the Cu and Fe atoms are not apt to get together on the atomic scale at low temperatures; this will lead to large fluctuations and phase separation in liquid Fe-Cu alloy.     

Atomic-scale computer simulation for early precipitation process of Ni75Al10V15 alloy

The kinetic model for a ternary system is introduced based on the microscopic diffusion form of the phase-field equations for a binary alloy. The equation is solved in the reciprocal space. This model is used to investigate the early precipitation process of Ni75-Al10V15 by simulating the atomic pictures of the two ordered phases and calculating the order parameters of γ′(Ni3Al) phase. Simulation results show that the γ′ ordered phases precipitate from the disordered matrix by a non-classical nucleation mechanism, and the nonstoichiometric γ′ ordered phase appears first and then transforms into the stoichiometric one. Clusters of V atoms appear at the γ′ phase boundaries followed by the formation of the nonstoichiometric θ ordered phase. The farther the location from γ′ phase boundary is, the lower the order degree of θ phase is. There exist two kinds of DO22 ordered domains: a horizontal one and a vertical one, related to their adjacent γ′ phase boundaries. The model could describe the atomic ordering and composition clustering simultaneously, and any a priori assumption about the new phase structure and precipitation mechanism etc. is unnecessary.     

Ni-Mo四近邻作用能对Ni75Al14Mo11合金沉淀行为影响的微观相场

基于微观扩散方程,采用微观离散格点相场法研究Ni-Mo原子间四近邻相互作用能对Ni75Al14Mo11合金沉淀过程微观机制的影响。通过原子尺度的结构演化图、表征浓度和有序度的成分序参数和长程序参数分析沉淀相的有序化、簇聚、镍原子反向析出及粗化行为等。研究结果表明:最近邻、第三近邻原子间作用能增大,可促进沉淀相的簇聚及有序化,但抑制后期镍基原子团簇的反向析出及粗化;次近邻、第四近邻原子间作用能增大的影响则与之相反;在相同条件下,外层作用能对沉淀相的有序化和簇聚影响最大。     

Atomic-scale computer simulation for early precipitation process of Ni75AlxV25-x alloy with intermediate Al composition

The microscopic phase-field approach is applied to model the early precipitation process of Ni75AlxV25-x alloy. Without any prior assumptions, this model can be used to simulate the temporal evolution of arbitrary morphologies and microstructures on atomic scale. By simulating the atomic pictures, and calculating the order parameters and volume fraction of the θ (Ni3V) and γ'(Ni3Al) ordered phases, we study Ni75AlxV25-x alloys with Al composition of 0.05, 0. 053 and 0. 055 (atom fraction). Our calculated results show that,for these alloys, θ and γ' phases precipitate at the same time; with the increase of Al content, the amount of γ' phase increases and that of θ phase decreases; the precipitation characteristic of γ' phase transforms from Non-Classical Nucleation and Growth (NCNG) to Congruent Ordering Spinodal Decomposition (CO SD) gradually; otherwise, the precipitation characteristic of θ phase transforms from Congruent Ordering Spinodal Decomposition (CO SD) to Non-Classical Nucleation and Growth (NCNG) mechanism gradually. Both θ and γ' phases have undergone the transition process of mixture precipitation mechanism characterized by both NCNG and CO SD mechanisms. No incontinuous transition of precipitation mechanism has been found.     

3 MeV 金离子辐照Ni60Nb40 非晶合金及Hastelloy-N 合金的辐照损伤研究

使用 3 MeV 金离子对Ni₆₀Nb₄₀ 非晶合金和Hastelloy-N 合金进行剂量为2.3×10¹⁵ cm^–2 和5×10¹⁶ cm^–2 的辐照实验。X 射线衍射(XRD)数据表明, Ni₆₀Nb₄₀ 非晶合金的非晶态在室温辐照下非常稳定, 而Hastelloy- N 合金在辐照后有明显的微观应变增加。同时纳米压痕分析表明, Ni₆₀Nb₄₀ 非晶合金的辐照软化和Hastelloy- N 合金的辐照硬化主要由原子移位损伤造成。使用原子力显微镜(AFM)测量半遮挡的辐照方法制造的肿胀台阶, 发现两种材料的辐照肿胀效应相差不大。扫描电子显微镜(SEM)观察发现, 室温条件下3 MeV 金离子导致Ni₆₀Nb₄₀ 非晶合金表面发生黏性流动的临界剂量大于2.3×10¹⁵ cm^–2, 而且发生线性流动的临界剂量具有不均匀性, 推测是由机械抛光时产生的表面应力造成。由于黏性流动可以有效修补表面缺陷, 所以Ni₆₀Nb₄₀ 非晶合金有希望作为抗腐蚀抗辐照涂层材料。     

过渡金属元素X(X=Ni,Ti,V)掺杂对Mg17Al12合金结构的影响

【目的】提高镁铝(Mg-Al)合金材料的储氢性能。【方法】基于密度泛函理论的平面波赝势方法,对过渡金属元素X(X=Ni,Ti,V)掺杂Mg_(17)Al_(12)合金体系的生成焓、电子结构、态密度、电荷密度等进行理论计算研究。【结果】过渡金属元素X替代合金中Mg元素的能量较低,其中Ni的掺杂性能较好;Ni的加入改善了Mg_(17)Al_(12)的储氢性能。且随着Ni浓度的升高,Mg_(17)Al_(12)合金的体积逐渐减小,总态密度峰值依次增大。【结论】过渡金属元素X(X=Ni,Ti,V)的掺杂可使镁铝合金的稳定性得到提升,与实验结果相符。     

合金钢γ→α转变温度的计算

采用Ｗagner的热力学模型，设计了计算程序，计算含Ｍn,Si,Ni,Cr,Mo,Cu,V,Nb,W,Co等１０种合金元素（合金含量＜７％）的多元系低合金钢的奥氏体－铁素体平衡及仲平衡温度，用该程序计算了多元系统合金钢的奥氏体－铁素体平衡温度，计算结果和实际,测量值符合得很好。     

B4C颗粒增强镍基合金喷涂层耐磨性研究

采用化学镀技术在B4C颗粒表面包覆一层镍合金层，并采用亚音速热喷涂技术制备了Ni60-B4C（包覆镍）涂层，在销盘式磨损试验机上进行涂层的磨粒磨损实验，结果表明：镍合金包覆层增大了B4C颗粒与涂层中Ni60基体界面的结合强度，阻止了B4C颗粒在火焰加热过程中的氧化分解，同时Ni60-B4C（包覆镍）复合涂层的耐磨性，随B4C颗粒含量（≤15％）的增加而增加。     

表面喷熔层超塑性变形强化及其协调变形条件

采用超塑性变形强化的新工艺对模具钢３ｒ２Ｗ８Ｖ的Ｎｉ６０喷熔层进行了研究，通过试验得到了３Ｃｒ２Ｗ８Ｖ基体和Ｎｉ６０热熔层间实现超塑性协调变形的工艺参数，并研究了异材间的超塑性协调变形条件，建立了超塑性协调变形的力学模型，对喷熔层的表面性能试验结果表明，超塑性变形工艺对喷熔层具有明显的强化作用，经超塑性变形处理的熔层基摩擦磨损，多次冲击和热疲劳性能均得到了显著提高。     

水溶液中镁-镍合金的电沉积合成

由于水溶液中镁离子的还原电位较负,镁难以从水溶液中沉积出来,且镁与镍的沉积电位相差2V以上,镁与镍很难共沉积,研究表明,镁一镍合金确实可以从一水溶液中沉积出来,镁一镍的共沉积也被XRD和AAS的分析所证实．XRD及循环伏安法研究还发现,沉积合金具有多相的结构,恒电流暂态极化实验表明镁一镍合金的电沉积过程是一成核长大过程．     

Dendrite growth and micromechanical properties of rapidly solidified ternary Ni-Fe-Ti alloy

The rapid solidification of undercooled liquid Ni_(45)Fe_(40)Ti_(15)alloy was realized by glass fluxing technique.The microstructure of this alloy consists of primaryγ-(Fe,Ni)phase and a small amount of interdendritic pseudobinary eutectic.The primaryγ-(Fe,Ni)phase transferred from coarse dendrite to fragmented dendrite and the lamellar eutectic became fractured with the increase of undercooling.The growth velocity ofγ-(Fe,Ni)dendrite increased following a power relation with the rise of undercooling.The addition of solute Ti suppressed the rapid growth ofγ-(Fe,Ni)dendrite,as compared with the calculation results of Fe-Ni alloy based on LKT model.The microhardness values of the alloy and the primaryγ-(Fe,Ni)phase increased by 1.5 times owing to the microstructural refinement caused by the rapid dendrite growth.The difference was enlarged as undercooling increases,resulting from the enhanced hardening effects on the alloy from the increased grain boundaries and the second phase.     

Effect of different deformation and annealing procedures on non-magnetic textured Cu<Subscript>60</Subscript>Ni<Subscript>40</Subscript> alloy substrates

In this work, a series of specimens was prepared by the casting method. Sharp cube-textured substrates were processed by heavy cold rolling and recrystallization annealing (i.e., the rolling-assisted biaxially textured substrates (RABiTS) method). Both the rolling and the recrystallization texture in the alloy tapes were investigated by X-ray diffraction and electron back-scatter diffraction, respectively. The results showed that a strong copper-type deformation texture was obtained in the heavy cold-rolled substrate. In addition, the recrystallization annealing process was found to be very important for the texture transition in the Cu–Ni alloy substrates. The cube texture content in the Cu₆₀Ni₄₀ alloy substrates reached 99.7% (≤10°) after optimization of the cold-rolling procedure and the recrystallizing heat-treatment process, whereas the content of low-angle grain boundaries (from 2° to 10° misorientation) in the substrate reached 95.1%.     

磁控溅射表面镀膜对Nd2Fe14B稀土永磁体抗腐蚀性能的影响

在Nd₂Fe₁₄B稀土永磁体基体表面,采用磁控溅射（直流+射频）技术制备了Ti/Ni,Ti/Al和Al/Ni等二元合金薄膜和Ti/Al/Ni三元合金薄膜。并通过中性盐雾试验、腐蚀失重计算、电化学腐蚀试验、金相观察等方式,对比研究了不同表面处理对Nd₂Fe₁₄B稀土永磁体基体抗腐蚀性能的影响,并构建了腐蚀模型。研究发现：Ti/Ni,Ti/Al和Al/Ni等二元合金薄膜和Ti/Al/Ni三元合金薄膜均有效地提高了Nd₂Fe₁₄B稀土永磁体基体耐中性盐雾腐蚀和电化学腐蚀的能力;Ti/Al/Ni三元合金薄膜较Ti/Ni,Ti/Al和Al/Ni等二元合金薄膜有更优良的综合耐腐蚀性能,其磁控溅射工艺参数为：Ar流量60 sccm,基片温度常温,Ni,Al,Ti的溅射功率都为250 W,基片转速20 r·min^-1,镀膜均速0.3 nm·s^-1,总计溅射时间1 h。     

Ti-6Al-4V合金镀渗Ni-P合金后的组织结构与耐磨性

本文对Ti-6Al-4V合全化学镀Ni-P合金后,在氩气中经1123K扩散0.5—7h试样的相组成、组织、硬度及耐磨性进行了研究。结果指出:渗层组织共分五层,其中最外层是由Ni_5P_2、Ni_3P和Ti_(1.7)P三种磷化物组成的混合物分布在Ni_3Ti基体上的复相组织,硬度高达HK900。 磨损试验在Skoda-Savin磨损试验机上进行。研究结果表明,Ti-6Al-4V经镀渗Ni-P后,从根本上消除了钛及钛合金在磨损过程中的粘着现象,从而极大地提高了耐磨性。     

钢铁材料中刃位错与溶质原子的交互作用

通过计算机编程建立了钢铁中铁素体相中的1/2[1 1 1]刃位错的原子结构模型,用实空间的连分数方法计算了碳、氮及合金元素在完整晶体及位错区引起的总结构能和环境敏感镶嵌能,讨论了碳、氮及合金元素在位错区的偏聚及交互作用.计算结果表明:轻杂质C,N易偏聚于位错芯处;强、中碳化物形成元素(Ti,V,Nb,Cr)易偏聚于刃位错线上,非碳化物形成元素Ni偏聚于位错线下方的弹性扩张区;轻杂质加剧强碳化物形成元素在刃位错区的偏聚,当温度下降使得C,N及合金元素的浓度超过其最大固溶度时,钢铁中刃位错区将有C,N金属间化合物脱溶,这些化合物会阻碍位错的运动,起到第二相粒子的强化作用.     

Surface modification of Ti-49.8at%Ni alloy by Ti ion implantation：phase transformation,corrosion, and cell behavior

The Ti?49.8at%Ni alloy was modified by Ti ion implantation to improve its corrosion resistance and biocompatibility. The chemical composition and morphologies of the TiNi alloy surface were determined using atomic force microscopy (AFM), auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS). The results revealed that Ti ion implantation caused the reduction of Ni concentration and the formation of a TiO2 nano-film on the TiNi alloy. The phase transformation temperatures of the Ti–TiNi alloy remained almost invariable after Ti ion implantation. Electrochemical tests indicated that the corrosion resistance of TiNi increased after Ti ion im-plantation. Moreover, the Ni ion release rate in 0.9% NaCl solution for the TiNi alloy remarkably decreased due to the barrier effect of the TiO2 nano-film. The cell proliferation behavior on Ti-implanted TiNi was better than that on the untreated TiNi after cell culture for 1 d and 3 d.     

支架用NiTi合金的表面改性方法研究进展

近等原子比的NiTi合金因其具有优异的超弹性、形状记忆效应以及良好的生物相容性,在医用植入领域得到了广泛的应用。然而,Ni离子的析出可能诱发过敏和炎症,因此需要对其进行表面改性。从表面氧化、电解抛光、表面涂层、接枝活性分子等方面综述了NiTi合金表面改性方法的研究进展,分析了各处理工艺的技术优势和局限性,指出了NiTi合金表面改性未来的发展趋势。     

Ni_2MnIn合金电子结构和微观磁性的第一原理计算

利用基于密度泛函理论的第一原理赝势法,研究了Ni2MnIn合金Heusler结构和四方马氏体结构的晶体结构参数、电子结构及微观磁性特征.通过对能带、各原子轨道磁矩和分波态密度(PDOS)的计算分析,发现二种结构中各原子的原子轨道磁矩、元胞轨道磁矩、元胞体积均变化不明显,两相均具有明显自旋极化现象.计算表明:四方马氏体相变导致Ni2MnIn元胞费米能下降0.495eV;Ni2MnIn结构中,In原子具有弱抗磁性,晶胞磁矩为Mn原子轨道磁矩所主导,约占元胞总轨道磁矩85%,Ni原子轨道磁矩贡献约占元胞总轨道磁矩15%.理论计算结果与其他理论值进行了对比.     

Zr基大块非晶的研究

利用射流成型法制备出Ｚｒ５２．５Ｃｕ１４．６Ａ１１０Ｔｉ５大块非晶,该合金系统具有很强的玻璃形成能力和宽的过冷区,其玻璃转化温度Ｔｇ＝６５０．６３Ｋ,晶化温度Ｔｘ＝７２１．９０Ｋ,过冷区△Ｔｘ＝Ｔｘ－Ｔｇ＝７１．２７Ｋ,Ｖｉｃｋｅｒ硬度为５５８ｋｇ／ｍｍ＾２,压缩断裂强度１７３０ＧＰａ,弹性模量８２ＧＰａ,观察其断口有大量纹络状河流花样,并有融化的液滴存在,该合金系统大的玻璃形成能力应归功于合金组