微量添加Fe元素对CuZrAl块体金属玻璃的结构和力学性能的影响(英文)

使用水淬法制备含微量Fe元素的CuZrAl块体金属玻璃。使用X射线衍射(XRD)检测其结构;采用DSC研究Fe元素的添加对块体金属玻璃热稳定性的影响,微量添加Fe元素显著拓宽了过冷液相区。Cu44Zr48Al7Fe块体金属玻璃的塑性应变约为1.5%。使用透射电子显微镜(TEM)观察其微观结构,结果发现,添加1%～2%Fe(摩尔分数)的CuZrAl合金中出现了相分离的富CuZr非晶相。     

Ni-Zr-Ti-Nb-M(M=Sn,Bi)块体非晶合金的形成及其磁性能研究

从共晶点、混合热、原子尺寸差和微合金化出发,设计了Ni-Zr-Ti-Nb体系具有较高玻璃形成能力的Ni基合金成分,用铜模吸铸法制备了直径2mm的块体非晶合金,用X射线衍射仪、差热扫描量热仪和振动样品磁强计检测了样品的组织结构、热稳定性和磁学性。结果表明:微量Sn的添加提高了合金的玻璃形成能力,制备出了准2mm的棒状完全非晶试样;Bi不利于提高Ni-Zr-Ti-Nb体系合金的玻璃形成能力。此外,微量Sn能使饱和磁感应强度稍有提高。     

Size Effect of Thermal Stability of Zr47Ti12.9Cu11Ni9.6 -Be16.7Nb2.8 Metallic Glass

采用真空铜模吸铸和单辊真空薄带技术制备出直径5 mm的Zr47Ti12.9Cu11Ni9.6Be16.7Nb2.8金属玻璃棒材和相同成分厚30μm的金属玻璃薄带。利用热分析技术和Kissinger方法分析计算了不同尺寸金属玻璃的热稳定性参数,主要包括:玻璃转变温度Tg,晶化温度Tx,玻璃转变和晶化激活能Eg、Ex等。结果表明:Zr47Ti12.9Cu11Ni9.6Be16.7Nb2.8金属玻璃在热稳定性上表现出"越小越稳定"的特征,薄带的热稳定性参数均高于棒材,表现出更好的热稳定性。不同尺寸Zr47Ti12.9Cu11Ni9.6Be16.7Nb2.8金属玻璃的晶化行为进一步验证了这一特征:在晶化温度远低于金属玻璃薄带情况下,棒材却更易晶化,晶化过程中获得了比金属玻璃薄带更加完整的晶化组织。     

焊缝金属含氧量对其韧性的相左影响

0前言 焊缝金属的韧性是由其组织和夹杂物等因素所左右的,而组织和夹杂物的种类、形态及数量等又与焊缝金属的化学成分和焊接过程的冷却速度等密切相关。在相同的冷却速度下,不同的焊缝成分会生成不同的微观组织。     

多元块体金属玻璃合金成分的本征设计——多元Miedema模型理论和等效键参数理论的应用

用多元Miedema模型理论和等效键参数理论对Gd(Tb)-Co-Al多元合金成分的块体非晶形成能力进行了预设计,针对预设计的合金成分用水冷铜模吸铸法制备出了一系列不同直径(1,3,5 mm)的Gd基合金样品.利用X射线衍射仪确定合金的结构,用热分析法研究了合金的玻璃转变、晶化和熔化行为.实验证明,采用多元Miedema模型理论和等效键参数理论能有效地进行块体非晶合金的成分设计,理论与实验结果能较好地符合.     

Ce对Sm-Cu-Ni-Al大块非晶玻璃形成能力及热稳定性的影响

用水冷铜模吸铸法制备出名义成分（at％，下同）为Sm55-xCexCu15Ni10Al20（x=0，7，10，13，15，20，25）的合金样品。利用X射线衍射仪确定合金的结构，用示差扫描量热计（DSC）研究合金的玻璃转变、晶化和熔化行为。通过过冷液相区宽度△Tx和约化晶化温度Tx／Tm来表征Sm基大块非晶的玻璃形成能力，用Tg和Tx来表征其热稳定性。结果表明，Ce的加入使Sm基块体金属玻璃热稳定性降低，当Ce含量为10at％时，其玻璃形成能力最强，可以制备出φ5mm以上的块体金属玻璃，同时应用Miedema理论和等效电负性差△X讨论了该系列合金的玻璃形成能力。     

简讯

电磁振动有效降低合金熔体玻璃化的临界冷却速度日本产业技术综合研究所早在1997年就已开发了利用交流电流与直流磁场产生的电磁振动使金属材料晶粒细化的技术。新近他们把这一技术利用来由熔融金属生产金属玻璃的过程中,在液态金属凝固的过程中施加电磁振动力时能有效地抑制凝聚体的结晶化,从而能以比传统冷却速度(要求105~106℃/s)低得多的冷却速度(103℃/s)生产金属玻璃,过去只能生产尺寸为mm级的微小粉末和薄箔产品,采取电磁振动技术之后则可以较低的冷速生产尺寸为cm数量级的大块金属玻璃。(《工业材料》,2005,53(6):13)铝合金纳米晶化…     

Effect of Al Addition on the Mechanical Properties and Microstructure of Zr35Ti30Cu7.5Be27.5 Bulk Metallic Glass

利用单轴压缩试验研究了用部分Al替代Zr对Zr35-xTi30Cu7.5Be27.5Alx(x=0,1,1.5,2,2.5,5,at%)块体金属玻璃力学性能的影响。研究表明,当添加Al含量为1.5at%和2at%时,所得到的块体金属玻璃的压缩塑性从0.95%(x=0)分别提高至15.10%(x=1.5)和3.45%(x=2)。利用扫描电子显微镜(SEM)对金属玻璃样品的断裂形貌进行了表面分析。利用透射电子显微镜(TEM)对不同Al含量的块体金属玻璃试样进行了微观结构表征,结果显示,Al含量为1.5at%和2at%的金属玻璃样品的微观结构呈现出了纳米级别的"微观不均匀性"。最后,结合临界剪切应力(CSS)讨论了微观结构与塑性变形行为之间的关联性。     

专利文献信息

一种制备TbDyFe基合金定向凝固晶体的方法，铜及铜合金表面铸渗工艺，一种镁合金轮毂的制造方法，使用薄带铸造法的纳米复合型永磁体用原料合金的制造方法，利用快速冷却技术制备块体金属玻璃的方法。     

焊缝金属中针状铁素体晶粒长大行为

以针状铁素体(AF)组织为基体组织的大热输入焊缝金属作为研究对象,采用金相显微镜(OM)、扫描电子显微镜电子背散射衍射装置(EBSD)、全自动静态相变仪等手段表征了焊缝金属内细长状的针状铁素体(AF)组织晶粒的取向特征,分析不同焊接热输入对焊缝金属内AF晶粒形核以及长大行为的影响规律. 结果表明,在大热输入焊接条件下,当焊缝金属的冷却速度低于临界冷却速度时,AF晶粒以多边形铁素体形态从夹杂物边缘开始形核时,此刻与母相奥氏体(γ)间偏离K-S关系,当焊缝金属温度降低至相变开始温度后,AF晶粒以细长的针状开始长大,并且与母相奥氏体间满足K-S关系. 但是随着焊接热输入降低,冷却速度逐步的加快,AF晶粒形核尺寸将越来越小,并且向着与母相奥氏体满足K-S关系的取向偏转速度加快,当焊缝金属的冷却速度超过临界冷却速度时,AF晶粒不用形核就可以迅速长大.     

Effect of glassy ribbon thickness on its anodic behavior

Electrochemical behavior of Fe₈₀B₂₀ glassy ribbons with thickness varying from 12 μm up to 30 μm has been investigated. Within the active dissolution region and passivation potential region all the ribbons exhibited the same anodic behavior. There were, however, large differences in the stability of the passive state; the thicker the ribbon (and, what follows, the broader the cooling profile) the less stable the passive state. SEM examinations together with KEVEX and SAM analysis revealed some localized chemical heterogeneities at the shiny side of the thicker ribbons. These were apparently the sources of weak spots within the passivating film.     

Stability,phase transformation and deformation behavior of Ti-base metallic glass and composites

Melt-spun ribbons and copper-mold cast cylinders of (Ti_0.5Cu_0.23Ni_0.2Sn_0.07)_100−xMo_x bulk glass-forming alloys are prepared. Both Ti₅₀Cu₂₃Ni₂₀Sn₇ and (Ti_0.5Cu_0.23Ni_0.2Sn_0.07)₉₅Mo₅ melt-spun glassy ribbons exhibit large supercooled liquid regions, high reduced glass transition temperatures, and good thermal stabilities. During continuous heating of the melt-spun ribbons, both alloys present a two-stage crystallization behavior. Mo slightly lowers the glass-forming ability but significantly decreases the temperature of the second stage crystallization. For both alloys, the stable phases after heating are Ti₂Ni, TiCu, Ti₃Sn and β-(Cu,Sn). As-cast Ti₅₀Cu₂₃Ni₂₀Sn₇ cylinders contain dendritic hcp-Ti solid solution precipitates, as well as interdendritic glassy and Sn-rich crystalline phases. The ultimate compression stress reaches 2114 MPa with 5.5% plastic strain for 2-mm diameter cylinders. Yielding occurs at 1300 MPa, and Young’s modulus is 85.3 GPa. Mo improves and stabilizes the precipitation of a β-Ti solid solution but prevents glass formation in as-cast (Ti_0.5Cu_0.23Ni_0.2Sn_0.07)₉₅Mo₅ bulk alloys. The bulk samples contain dendritic β-Ti solid solution precipitates, Ti₂Ni particles and Sn-rich phases. The ultimate compression stress is 2246 MPa with about 1% plastic strain for a 3-mm diameter cylinder. σ_0.2 is about 1920 MPa and Young’s modulus is 104 GPa. The high strength is attributed to both Mo solution strengthening and Ti₂Ni particle strengthening. The limited ductility is induced by the precipitation of brittle Ti₂Ni particles.     

Bulk ferromagnetic glasses in the Fe–Ni–P–B System

The ferromagnetic metallic glass Fe₄₀Ni₄₀P₁₄B₆, available only as 30–50 μm thick ribbons, has been extensively studied over the last three decades. We used a flux-melting and water-quenching technique to prepare bulk glassy Fe₄₀Ni₄₀P₁₄B₆ alloys in the form of 2-mm diameter spheres and 1-mm diameter rods. The Curie temperature for the bulk glasses is higher than the average value of Curie temperatures reported for the rapidly quenched ribbons. The glass-transition temperature and the crystallization temperature of the bulk glasses are lower and higher, respectively, than the average values reported for rapidly quenched ribbons, making the supercooled-liquid region as wide as 42 K. The bulk glasses crystallize by a homogeneous nucleation followed by a growth at a constant rate. The nucleation rate in the bulk glasses is four orders of magnitude lower than in the rapidly quenched ribbons, suggesting that the previous thickness limitation was due to impurities in the melt (heterogeneous nucleation).     

Synthesis and mechanical properties of cast quasicrystal-reinforced Al-alloys

We report on the preparation and mechanical properties of Al-based-composites with quasicrystalline particles as reinforcement. Al–Mn–Ce/Fe and Al–Mn–Pd bulk samples were synthesized by die casting into a copper mould at moderate cooling rate. Thin ribbons were prepared by melt-spinning as a reference state for the phase formation under most rapid quenching conditions. Microstructural analysis was done using X-ray diffraction, scanning and transmission electron microscopy as well as calorimetric methods. Significant differences in the phase formation, the composite microstructure and the thermal stability of the microstructure were found for different alloy compositions. The deformation behaviour was characterized by constant-rate compression tests at room temperature for a number of alloy variations yielding excellent properties compared to conventionally produced Al-alloys. The mechanical properties vary within a wide range of strength and ductility as a function of the quasicrystal volume fraction and their morphology. Also first tests at elevated temperatures were carried out, revealing a promising high temperature stability of the composite.     

快淬Fe_(85)Ga_(15)合金的显微组织和磁致伸缩性能

采用熔体快淬方法制备了不同辊速(v=12m/s、15m/s、20m/s)条件下的Fe_(85)Ga_(15)合金薄带样品,对薄带样品的组织结构和磁致伸缩性能进行了研究.结果表明,合金薄带的组织结构和磁致伸缩性能与快淬时的冷却速度密切相关,v=20m/s辊速条件下制备的薄带在磁场为45kA/m时,其磁致伸缩系数λ达-125×10~6,伸缩曲线尚未完全饱和.对薄带组织形貌的观察表明,薄带样品内晶粒沿薄带厚度方向呈现出取向性排列.XRD分析表明,辊速的提高可以抑制有序DO_3相的析出,α-Fe相和非对称DO_3结构的Fe_3Ga相衍射峰发生重叠并有劈裂现象.TEM分析表明,合金基体中存在着富Ga原子团簇.薄带样品大的磁致伸缩系数主要来源于样品强的形状各向异性和非平衡制备条件下合金内部的特殊晶体结构.     

磁性金属玻璃研究进展

磁性金属玻璃是一种新型的磁性材料,它具有大的玻璃形成能力和良好的热稳定性,只需很低的临界冷却速率即可获得很大尺寸的金属玻璃。与传统的磁性材料相比,磁性金属玻璃的有关性能更加优异,它具有高的饱和磁化强度,低的矫顽力,高的磁导率以及大的磁致伸缩系数,而且,在其液态过冷区内具有超塑性,利用这一特点,可以将其加工成为各种高精密度形状复杂的磁性器件。     

Ni- and Cu-free Ti-based metallic glasses with potential biomedical application

In the present work Ti–Fe–Si and Ti–Fe–Si–X (X = Zr, Pd, Ge) glassy alloys are discussed as potential biomedical materials. Depending on composition and experimental conditions these alloys possess glassy, quasicrystalline or crystalline structure. The glassy state and crystallization behavior of the melt spun ribbons were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and the Hank's solution was used as simulated body fluid for corrosion tests. Ternary Ti–Fe–Si alloys near the Ti₆₅Fe₃₀Si₅ eutectic point were prone to form quasicrystals if the cooling rate was not high enough to retain amorphous structure. The compositions on the steeper side of the eutectic point could be vitrified. The results indicate that small additions of Zr can have a positive effect on glass formation, while additions of Ge, Pd may have a detrimental effect by promoting crystallization. Ti–Fe–Si and Ti–Fe–Si–Zr alloys exhibited high corrosion properties, superior to that of pure Ti and most of Ti-based glassy alloys reported in the literature. Being free of Ni and Cu this group of alloys may be considered for possible biomedical application.     

压力对非晶Fe78Si9B13的热性能和耐腐蚀性能的影响（英文）

室温下,对非晶Fe78Si9B13条带进行压力处理,通过不同的实验手段检测其热性能和耐腐蚀性能。XRD和热膨胀数据显示经过压力处理后Fe78Si9B13条带仍保持非晶状态,并且其内部自由体积数量随着压力的增加而单调增加。在10MPa的压力条件下非晶条带在不同溶液中的耐腐蚀性能减弱,在20MPa的压力条件下耐蚀性能增强,这种非线性变化与电阻率变化结果一致。可以通过由于压力引入样品中而导致自由体积的数量和硅原子的偏析来解释这一非单调变化。     

Thermal behaviour of Pd40Cu30Ni10P20 bulk metallic glass

The thermal behaviour of differently milled Pd₄₀Cu₃₀Ni₁₀P₂₀ bulk metallic glass through the glass transition has been investigated by in situ high-energy synchrotron X-ray diffraction. Repeated heating and cooling were performed between the glassy and the supercooled liquid state. The changes in positions and intensities of the first and second diffraction maxima of the as-milled powder indicate irreversible changes during first heating up to the glass transition temperature T_g due to structural relaxation. After annealing, reversible structural changes with temperature are observed upon heating and cooling in the glassy phase, and in the supercooled liquid state respectively. The shift in the position of the first maximum scales approximately with the linear thermal expansion for the glassy state; however, this relation does not hold for the supercooled liquid. The structural transition from the glass to the supercooled liquid at the glass transition temperature is reflected by the intensity of the diffraction maxima and by a reversed temperature dependence of the position of the second diffuse maximum below and above T_g. The changes of the glass structure for the decrease of free volume by annealing are found to be different from those observed for the reversible volume expansion or shrinkage by varying the temperature. Therefore, the shift of the first diffuse maximum position of bulk metallic glasses cannot be used as a measure of the change in free volume.     

Laser surface coating of Fe-Cr-Mo-Y-B-C bulk metallic glass composition on AISI 4140 steel

Fe-based bulk metallic glasses exhibit very high hardness, elastic modulus/limit and wear/corrosion resistance. In the present investigation, an attempt has been made to develop an amorphous coating with Fe₄₈Cr₁₅Mo₁₄Y₂C₁₅B₆ bulk metallic glass on AISI 4140 substrate by laser surface processing. Following coating, the microstructure and phase aggregate were analyzed by scanning electron microscope and X-ray diffraction, respectively. Microhardness and wear resistance were assessed using Vickers microhardness tester and ball-on-plate wear testing machine, respectively. The coating thickness varied directly with incident laser power and interaction time. Despite trials with wide range of process parameters, the present experiments were unable to retain complete amorphous surface microstructure after laser surface coating. Numerical prediction of the thermal profile and related parameters suggest that the cooling rate and thermal gradient experienced by the coated zone were fairly high. Yet failure to retain amorphous/glassy microstructure of an otherwise bulk metallic glassy alloy suggests that compositional changes (solute redistribution) within the coated zone and across the coating-substrate interface are responsible for nucleation and growth of crystalline phases from the melt. However, correlation between coating parameters and surface microstructure and properties allowed determination of the optimum conditions that ensured fine grained uniform microstructure with a significant improvement in hardness and wear resistance.