Electrochemical behavior of partially crystallized amorphous Al86Ni9La5 alloys

The Al₈₆Ni₉La₅ amorphous ribbons were annealed at 503 K for different time to obtain partially crystallized alloys with the different volume fractions of α-Al phase, and the effect of the crystallization extent on the electrochemical behavior of the ribbon was investigated in 0.01 M NaCl solution. The results show that the corrosion resistance of the partially crystallized ribbons is higher than that of the as-spun ribbon with the fully amorphous structure, and the corrosion resistance of the partially crystallized alloy is strongly dependent on the volume fraction of α-Al phase. The partially crystallized ribbon containing about 20 vol% α-Al phase exhibits the highest corrosion resistance.     

Zr-Al-Ni-Co块体非晶合金的成分设计

选择Zr-Al-Ni-Co合金系为研究体系,以等电子浓度和等原子尺寸为判据设计8种合金,采用吸铸法制备了直径为3 mm的合金棒,XRD结果表明了在等电子浓度面和等原子尺寸面交线上存在着一个较大范围的块体非晶合金形成区域.能够形成块体非晶合金的7种合金,具有相近的约化玻璃转变温度Trg值,最大达到0.589;它们的玻璃转变温度Tg值略有差异,且从三元Zr-Al-Co一侧至三元Zr-Al-Ni一侧,其值逐渐减小,最高Tg=713 K.将Zr-Al-Ni-Co合金系与用相同方法设计的块体非晶合金Zr-Al-Ni-Cu和Zr-Al-Ni-Fe体系进行了比较.     

热喷涂工艺制备铝基非晶态合金材料研究进展

传统的铝基非晶态合金的制备方法有急冷法和机械合金化法.急冷法使用方便,冷却速率快,可获得非晶,可实现连续生产;机械合金化法具有设备简单,操作方便,易工业化,合金成分范围相对较宽等优点.但是这两种方法只限于制备非晶条带、薄片或粉末,而且生产制备周期较长,生产效率较低.热喷涂技术作为一种新兴的制备工艺,可获得非晶涂层,实现...     

ZrTiCuNiBe块体非晶合金的热电阻特性及电子结构

为了揭示ZrTiCuNiBe块体非晶合金的物理性能,利用电弧炉熔炼及铜模快速铸造的方法,制备Zr41.2Ti13.8Cu12.5Ni10Be22.5块状非晶合金.通过测量热电阻系数和电子能谱,研究了块体非晶合金的热电阻特性和电子结构.研究表明:电阻率随着温度升高而降低,紧临晶化前未出现电阻率极大现象;块体非晶态合金与晶态纯金属相比,锆的电子结合能不发生变化,其余元素电子结构明显改变.     

Formation of amorphous anodic oxide films of controlled composition on aluminium alloys

Binary, non-equilibrium Al-29at%Nb, Al-44at%Ta, Al-19at%Ti, Al-25at%Ti and Al-32at%Zr alloys were prepared by magnetron sputtering and subsequently anodized at high Faradaic efficiency to grow barrier-type anodic films. Examination in the transmission electron microscope revealed amorphous anodic films of relatively uniform compositions across the film thicknesses, except for a layer of relatively pure alumina, of about 5% of the film thickness, present at the film/electrolyte interface of the Al-Ta alloy. The film compositions, from Rutherford backscattering spectroscopy, indicate that the alloy constituents are oxidized in their alloy proportions to form films comprising intimately mixed units of the various oxides, namely alumina, niobia, titania, tantala and zirconia. The films grow by co-operative transport of metal and oxygen ions under the electric field with formation of film material by both migration of metal ions outwards and of oxygen, and possibly hydroxyl, ions inwards. The average migration rates of Al³⁺, Nb⁵⁺, Ti⁴⁺ and Zr⁴⁺ ions are similar, to within 10%, but Ta⁵⁺ ions migrate more slowly than Al³⁺ ions. The results of the study show that a wide range of compositions of amorphous oxide films can be readily formed by anodic oxidation of appropriate alloys, including compositions containing units of normally crystalline anodic oxides, namely TiO₂ and ZrO₂.     

铝基合金水解制氢的研究进展

铝是地壳中含量最丰富的金属元素,也是一种重要的轻金属。由于其活泼的化学性质和较高的能量密度,铝作为一种新型能源材料正日益受到人们的关注。综述了国内外铝基合金水解制氢的研究进展,在对比分析各种铝基合金水解制氢性能以及成本等基础上,提出了铝基合金水解制氢的发展方向。     

无压渗透法制备BN增强铝基复合材料

本文讨论了无压渗透法制备BN增强铝基复合材料的制备过程和粉体成分对于渗透的影响.采用无压渗透法制备了BN增强Al基复合材料.在800℃、N2气氛中,铝基合金可以自发的渗入Al-Mg-BN粉体.实验结果显示,渗透气氛、Mg、粉体的烧结对于无压渗透过程有重要影响.     

Compressive fracture behavior of Cu-based bulk amorphous alloys

The mechanical properties of newly developed Cu_52.5 − xTi₃₀Zr_11.5Ni₆Al_x (x = 0, 1, 1.5, 2 at.%) bulk amorphous alloys were investigated under compressive condition. They exhibit high fracture strength of 2212 MPa, 2165 MPa, 2209 MPa and 2286 MPa, respectively. Three distinct vein patterns corresponding to the different zones can be observed on the fracture surfaces of the samples. Fracture propagation along two different directions and formation of striated vein patterns may contribute to the higher compressive fracture strength of the tested Cu-based bulk amorphous alloys.     

Development of new Al-based nanocomposites by mechanical alloying

Al-based binary (Al–Mg) and ternary (Al–Mg–Zr) elemental powder mixtures were mechanically alloyed to develop new Al–Mg–Zr nanocomposite materials. The phase evolution was studied in the as-milled and heat-treated powders by XRD and TEM/EDS analyses. For the binary Al–Mg alloy, the predominant phase was an Al(Mg) solid solution (SS) and an amorphous phase was not possible to be synthesized. Upon adding 5 at.% Zr to the Al–10Mg blended powder, some free Mg was present in addition to the formation of an Al(Zr,Mg)SS, which transformed to the Al₃Zr intermetallic after annealing. When the Zr content was increased a nanocomposite of a solid solution and an intermetallic was obtained with considerable improvement in terms of structural stability and hardness. The presence of an oxide phase at 35% Zr might be responsible for the increased hardness in this particular alloy.     

非晶态Ni—Si—B系合金在FeCl3溶液中的腐蚀行为

用失重法研究了几种Ｎｉ－Ｓｉ－Ｂ系合金在ＦｅＣｌ３溶液中腐蚀行为，分别考查了腐蚀速率与材料组分，表面状态，溶液温度，浓度及ｐＨ值的关系。结果表明：随着Ｎｉ含量增加，表面状态越粗糙，溶液浓度增加，温度升高，ＰＨ值降低，均将使腐蚀速率增加。     

TEM study of the indentation behaviour of thin Au film on GaAs

Au films of 8.9 nm thickness have been sputter deposited onto a (001) GaAs substrate at room temperature. An average grain size of 10 nm and no texture were obtained. Subsequent, nanoindentation tests were performed on the coated specimens and the mechanical response was compared to that of a bulk GaAs sample with the same crystallographic orientation. Furthermore, the loading–unloading curves were analysed in view of transmission electron microscopy plan-view images obtained on the deformed substrate–film specimens and compared to results previously reported in the literature for bulk sample. Constrained plasticity of the films was observed to occur for residual depth to thickness ratio below 0.67. Further, plastic deformation of the substrate happened on coated specimens at loads less than those required to plastically deform bare substrate.     

Fe-Si-B-P-Mo系高饱和磁感应强度非晶软磁合金

通过在Fe-Si-B-P合金体系中微合金化添加Mo元素,并提高铁含量,成功制备了具有较强非晶形成能力和优异软磁性能的非晶软磁合金。研究发现,Mo元素微合金化能有效提高合金的非晶形成能力,1%的Mo可以将该非晶合金体系的Fe含量极限提高到84%以上,从而得到了饱和磁感应强度(Bs)高达1.63 T的非晶合金。其中Fe80Si4.75B9.5P4.75Mo1非晶合金可以铸造形成非晶块体样品,临界直径达到1mm,饱和磁感应强度达到1.54 T,矫顽力为1.9 A/m。在整个成分范围内,该合金体系都具有1.9~5.1 A/m的低矫顽力和高于传统Fe-Si-B合金的饱和磁感应强度(Bs),具有较好的应用前景。     

化学镀法制备镍系非晶态合金的研究及应用进展

化学镀法制备的镍系非晶态合金材料以其高催化活性、超强的耐腐蚀性和耐磨性而得到广泛应用.本文概述了化学镀法制备非晶态合金材料的特性,综述了近年来化学镀法制备非晶态合金的研究进展及其在催化、防腐及耐磨材料等领域的应用.阐述了现阶段化学镀废液造成的环境问题及其净化和再利用方面取得的进展,对化学镀法制备非晶态合金的发展进行了展望。     

TEM analysis of InMnAs layers and dots prepared by low pressure MOVPE

The properties of InMnAs epitaxial layers and quantum dots prepared on (100) GaAs substrates using Metal-Organic Vapor Phase Epitaxy (MOVPE) are reported. Transmission Electron Microscopy (TEM) observation confirmed that the quantum dot structures were plastically relaxed. The degree of relaxation depends on the amount of Mn incorporated in the structure. Moiré fringes at TEM plan view images were used to evaluate strain in the InMnAs quantum dot structures. TEM observation confirmed that the InMnAs dots were uniform and they grew in the zinc-blende structure. The bright field TEM micrographs (cross-sectional) of the epitaxial layers showed the presence of InMnAs precipitates located under the interface between the InMnAs and substrate.     

大块非晶合金的性能、制备及应用

综述了大块非晶合金的性能、制备方法及应用，对比了吸铸法制备的棒状Zr41.2Ti13.8Cu12.5Ni10Be22.5,Zr57Cu20Al10Ni8Ti5,Zr52.5Ti5Cu17.9Ni14.6Al10(原子分数)大块非晶样品的过冷温度区间宽度(△Tx)，给出了3种大块非晶合金系列的热稳定性参数Tg、Tx及△Tx，提出了大块非晶合金领域存在的问题及发展方向．     

Preparation of H-bar cross-sectional specimen for in situ TEM straining experiments: A FIB-based method applied to a nitrided Ti-6Al-4V alloy

The in situ tensile straining of cross-sectional specimens inside a TEM is intrinsically very difficult to perform despite its obvious interest to study interfaces of surface treated materials. We have combined a FIB-based method to produce H-bar specimens of a nitrided Ti-6Al-4V alloy and in situ TEM straining stage, to successfully study the plastic deformation mechanisms that are activated close to the nitrided surface in the Ti-based alloy.     

The mechanism of order-induced intrinsic embrittlement in a stoichiometric Ni4Mo alloy by TEM and 3DAP characterization

To illustrate the mechanism of order-induced intrinsic embrittlement in a stoichiometric Ni₄Mo alloy, TEM and 3DAP were employed to investigate the phase separation during ordering in this paper. It showed that the atomic ordering initiated homogeneously, but some oriented ordered domains can grow preferentially later. Therefore, with atomic ordering, the average ordered domain size continues to increase, which improves the yield strength and ultimate strength due to increasing the critical shear stresses. However, except the growth of ordered phase, different phases with enriched molybdenum and depleted molybdenum were formed after ordering. The depleted molybdenum phase gradually reduces the Mo composition, which deteriorates the ultimate strength, and meantime the strength of grain boundary does not enhance, or even weakens. Hence, the atomic ordering induces embrittlement.     

Crystallization of Al-based Amorphous Alloys in Good Conductivity Solution

The corrosion-induced crystallization of Al94 exNixGd6（x=6 and 10, in at.%） metallic glasses as well as phase separation, oxidation and cracking in good conductivity solution has been investigated by various techniques.The transmission electronic microscopy（TEM） result reveals that crystalline intermetallics and oxides present on the electrochemically thinned hole edge, and the phase separation occurs in the matrix of the as-spun ribbons with the circumferential speed Rcof 29.3 m/s. In addition, the bending and cracking of the samples occur after corrosion. The influence of Ni content on the phase separation, bending and cracking can be explained by the fact that the percolation of the backbone clusters in the amorphous alloy melts and glasses is enhanced by increasing the composition of Ni.     

Fe基非晶合金的恒导磁性能研究

研究了Fe基非晶合金在不同热处理工艺条件下的恒导磁性能.结果表明,通过简单的横向磁场热处理工艺,可将具有高饱和磁感应强度的Fe基非晶合金制成无间隙的恒导磁磁芯,并且具有良好的综合磁特性.合金在350℃处理时,恒磁范围达到400A/m,磁导率约为3.14×10-3T·m/A,随保温时间的延长,恒磁场范围提高到600A/m以上,但磁导率降低,约为1.25×10-3T@m/A.在晶化温度以下,提高横向磁场热处理温度有利于提高材料的恒导磁性能.