ZrCuNiAl块体非晶合金的玻璃形成能力与动力学行为

利用铜模铸造法制备了Zr53Cu187Ni12Al16.3、Zr519Cu23.3Ni105Al14.3和Zr50.7Cu28Ni9Al12.3块体非晶合金,3种合金形成非晶的最大临界尺寸分别为6 mm、10 mm和14 mm.采用三点压弯式黏度仪、差热分析仪(DTA)研究了上述非晶合金过冷液体的黏度、脆性系数及临界冷却速度对玻璃形成能力的影响.结果表明:在3种合金中,Zr50.7Cu28Ni5Al12.3不仅具有最高的过冷液体黏度,而且具有最低的动力学脆性系数m (51.2)和临界冷却速率Rc(9.8 K/s),这导致该合金具有极强的玻璃形成能力.     

Cu50 Zr42 Al8块体金属玻璃的组织和力学性能

采用悬浮熔炼-铜模吸铸法制备了Cu50Zr42Al8块体金属玻璃,研究了其楔形试样的组织演变.随着熔体凝固过程中冷却速度的变化,楔形试样中存在表面全非晶区,中心晶体区以及二者之间的过渡区域,并确定Cu50Zr42Al8块体金属玻璃临界尺寸为4.8 mm.分别考察了φ4 mm铸态完全非晶棒和φ5 mm非晶复合棒的力学性能.φ4 mm非晶棒的压缩断裂强度,弹性应变和塑性应变分别为2260 MPa,2.0%,0.4%,几乎没有塑性变形.而φ5 mm铸态非晶复合棒的屈服强度、断裂强度分别为1670MPa、1849 MPa,弹性应变和塑性应变分别为1.6%和1.9%.非晶基体中存在的马氏体相CuZr和正交晶相Cu10Zr7的竞争影响了非晶复合棒的最终力学行为.     

Cu_(50-x)Zr_(40+x)Al_5Nb_5合金非晶形成能力、组织结构及力学性能研究

选择Cu50-x Zr40+x Al5Nb5(x=0,2,4,6)合金,研究主要元素成分变化对非晶形成能力和组织的影响,分析了组织结构和力学性能的关系。结果表明,玻璃形成最优成分为Cu46Zr44Al5Nb5,ΔTx、Trg、γ参数分别为51.9 K,0.60,0.401,具有良好的热稳定性。全非晶结构的Cu46Zr44Al5Nb5合金其断裂强度高达1811 MPa,无明显宏观塑性变形;断口表面较平整,且伴有明显的脉络状花样大面积的分布在断面上,扩展方向一致。非晶-晶体复合结构的Cu44Zr46Al5Nb5合金具有较好综合力学性能,其断裂强度达到1747 MPa,塑性应变为3.94%;断口平滑区分布着大面积细密且深的脉络状花样,剪切带宽度约为40μm,与压缩轴向约成45°。Cu44Zr46Al5Nb5合金析出结晶相的尺寸小于剪切带的宽度,且分布均匀,外力加载时对非晶基体起到一定的增韧作用。结晶相的组织结构和尺寸分布决定了非晶-晶体复合材料的力学行为。     

氧含量及过热度对铸态Zr52.5Cu17.9Ni14.6Al10Ti5大体积玻璃合金微观组织结构及力学性能的影响

利用射流成型法制备了厚度为2mm的Zr52.5Cu17.9Ni14.6Al10Ti5金属玻璃薄板,通过控制氧含量和过热度来改变玻璃薄板中淬态结晶相的体积分数。研究表明：低的氧含量水平和高的过热度有利于提高该合金的 玻璃形成能力,形成完全非晶的合金;完全非晶的2mmZr52.5Cu17.9Ni14.6Al10Ti5大体积金属玻璃薄板其断裂应力为1710MPa,弹性模量为80GPa,弹塑性为2.2%,提高合金中的氧含量水平或者降低熔体过热度都有利于结晶相析出,基体中出现2%和6%的结晶相时,断裂应力分别降为1580MPa和1220MPa。淬态结晶相的析出改变了Zr52.5Cu17.9Ni14.6Al10Ti5大体积金属玻璃剪切流变的变形方式,使材料脆断。     

ZrCuAlSi大块非晶合金形成及力学性能

通过铜模铸造法制备(Zr47Cu44Al9)100-xSix(x=0,0.5,1.5,2.5)大块非晶合金.利用差热分析、X射线衍射、显微硬度和室温压缩试验.研究分析添加Si元素对Zr47Cu44Al9合金非晶形成能力、热稳定性及力学性能的影响.结果表明,适量Si的加入能显著提高非晶合金的热稳定性,当Si的加入量为1.5时,合金具有最大的非晶形成能力,其纯非晶试样的临界尺寸由Zr47Cu44Al9的4 mm增大到(Zr47Cu44Al9)98.5Si1.5的6 mm.Si提高非晶形成能力的原因主要是抑制了引起异质形核的CuZr相的形成与析出.力学性能实验显示,显微硬度(Hv)随Si的加入由Zr47Cu44Al9合金的5850MPa增呔到(Zr47Cu44Al9)98.5Si1.5合金的6220 MPa,(Zr47Cu44Al9)98.5Si1.5合金的断裂强度为1862 MPa.     

添加微量Fe对Zr_(55)Al_(10)Ni_5Cu_(30)块体金属玻璃非晶形成能力和力学性能的影响(英文)

通过磁悬浮熔炼和铜模吸铸法制备直径3mm的(Zr0.55Al0.10Ni0.05Cu0.30)100-xFex(x=0,1,2,3,4)合金试样,研究Fe元素的微量添加对Zr55Al10Ni5Cu30块体金属玻璃非晶形成能力和力学性能的影响。研究表明,合理添加Fe元素(不超过3%,摩尔分数)导致约化玻璃转变温度Trg(=Tg/Tl)和参数γ(=Tx/(Tg+Tl))增大,因而其非晶形成能力增大,但添加过量的Fe元素(4%)会导致其非晶形成能力的降低。添加Fe元素也会显著地改善Zr55Al10Ni5Cu30块体金属玻璃的压缩塑性及提高其压缩断裂强度,当Fe元素的添加量为2%时,直径3mm、长度6mm的试样在压缩时出现一定的塑性及加工硬化现象。Fe元素添加量为4%形成的金属玻璃基复合材料,同样也显示良好的压缩塑性和高的压缩断裂强度。     

Ag和Fe元素添加对Cu-Zr-Al系非晶形成能力和力学性能的影响

以Cu-Zr-Al三元系为基础,研究Ag和Fe合金组元添加对块体金属玻璃(BMG)及BMG基复合材料的非晶形成能力和力学性能的影响.在Cu-Zr-Al三元合金体系中,Cu50Zr42Al8系BMG的△Tx=61 K,Trg=0.624,γ=0.416.适量添加Ag元素能显著地提高非晶形成能力:在Cu-Zr-Al-Ag四元合金体系中,Cu43Zr45Al8Ag4、Cu45Zr42Al8Ag5、Cu40Zr44Al10Ag6、Cu43Zr41Al8A98和Cu36Zr48Al8Ag8的Trg分别为0.618、0.625、0.618、0.628和0.598,γ值分别为0.424、0.427、0.424、0.432和0.433,△TX分别为77、76、78、84和108 K.在(Cu0.36Zr0.48-Al0.08Ag0.08)100-XFex(x-=0,3,5,10,15,20)五元体系中,Fe的添加明显影响合金的非晶形成能力;尽管△TX和Trg呈下降趋势,但(Cu0.36Zr0.48Al0.08Ag0.08)97Fe3块体非晶合金仍具有较高的非晶形成能力,其△TX=103 K,Trg=566,γ=0.424:Fe的适量加入可显著提高合金的力学性能,其中(Cu0.36Zr0.48Al0.08Ag0.08)95Fe5合金的强度和塑性应变分别提高至2 249 MPa和4.9%.Fe元素的存在导致Cu36Zr48Al8Ag8合金中产生明显的相分离,使(Cu0.36Zr0.48Al0.08Ag0.08)100-xFex合金得到增强增韧.     

Zr含量对非晶合金非晶形成能力及力学性能的影响

采用铜模吸铸法制备出直径为3 mm的[Zr0.72+x(Cu0.59Ni0.41)0.28-x]88Al12(x=0,0.05,0.1)棒状非晶合金。通过X射线衍射(XRD)、差示扫描热量法(DSC)、微机控制电子式万能力学试验机和扫描电镜(SEM)研究其非晶形成能力与压缩力学性能的变化规律。结果表明:随着Zr含量的提高,合金的过冷液相区宽度ΔTx减小,热稳定性下降;约化玻璃转变温度Trg和参数γ均随着Zr含量的提高而下降,非晶形成能力下降;在x=0时,断裂强度、塑性应变和抗压强度均达到最大值,分别为1 531 MPa、14.61%和1 838 MPa;而在x=0.1时,塑性应变和抗压强度则分别达到最小值5.06%和1 495 MPa;试样的室温准静态压缩力学性能随Zr含量的增加而下降。     

不同直径的Zr60.3Ni16.2Cu13.5Al10块体非晶合金的力学性能

采用铜模吸铸法制备了阶梯型的Zr60.3Ni16.2Cu13.5Al10非晶合金,利用X射线衍射(XRD)分别对直径为3 mm、4 mm、6 mm的合金试样进行结构分析,利用万能试验机及扫描电镜对试样进行压缩试验和断口形貌分析.研究表明,由于冷却速度的影响,直径为3 mm时是非晶结构,直径为4 mm和6 mm时是中心晶体和表面非晶体混合结构;对于Zr60.3 Ni16.2Cu13.5Al10合金,直径为3 mm时断裂强度可达到1 775 MPa,塑性变形可达到2.02%,而直径为4 mm的非晶复合材料的塑性变形可达2.93%,适当体积的晶体相的加入可以有效地提高非晶材料的塑性.     

冷却速率对Zr61.6N16.6Cu13.8Al8非晶合金力学性能的影响

采用铜模吸铸法制备了阶梯形的Zr61.6N16.6Cu13.8Al8非晶合金，利用x射线衍射（XRD）分别对不同直径的合金试样进行结构分析，利用万能试验机及扫描电镜对试样进行压缩试验和断口形貌分析。研究表明，由于冷却速度的影响，合金试样直径为3mm时是非品结构；直径为4mm和6mm时晶体相增多，甚至为完全晶体相结构；对于Zr61.6N16.6Cu13.8Al8合金，直径为3mm时的断裂强度可达到1703MPa，塑性变形可达到1．7％，适当体积晶体相的加入可以有效提高非晶材料的塑性。     

X-ray diffraction study of Ba0.985Na0.015Ti0.985Nb0.015O3, Ba0.6Na0.4Ti0.6Nb0.4O3 and Ba0.3Na0.7Ti0.3Nb0.7O3 compositions

The Ba_0.985Na_0.015Ti_0.985Nb_0.015O₃, Ba_0.6Na_0.4Ti_0.6Nb_0.4O₃ and Ba_0.3Na_0.7Ti_0.3Nb_0.7O₃ compositions of the (1 − x) BaTiO₃–xNaNbO₃ (BTNNx) system have been studied by X-ray diffraction and by measurements of dielectric properties. The specimens with composition BTNN (x = 0.015, 0.40 and 0.70) have been refined by the JANA program from X-ray powder diffraction data. Ceramic samples with composition (1 − x) BaTiO₃ + xNaNbO₃ (where x = 0.015, 0.40 and 0.70) were prepared by calcinations from appropriate mixture of BaCO₃, TiO₂, Na₂CO₃ and Nb₂O₅. The calcined powder was sintered at temperature range 1200–1400 °C. As the composition x increased from 0.015 (and 0.70), the ferroelectric ceramics (x = 0.015, FE) with tetragonal phase changed to the ferroelectric relaxors (RFE, x = 0.40). RFE ceramics showed a peculiar diffuse phase transition and dielectric relaxation at the low temperature (down to 180 K) due to a frustration between RFE and FE state. These ceramics present the classical ferroelectric character when 0 ≤ x < 0.075 and 0.55 < x ≤ 1 and relaxor character when 0.075 ≤ x ≤ 0.55.     

Magnetic, electrical and plastic properties of Fe76Nb2Si13B9, Fe75Ag1Nb2Si13B9 and Fe75Cu1Nb2Si13B9 amorphous alloys

Influence of 1 h annealing in vacuum on magnetic, electrical and plastic properties of Fe₇₆Nb₂Si₁₃B₉, Fe₇₅Ag₁Nb₂Si₁₃B₉ and Fe₇₅Cu₁Nb₂Si₁₃B₉ melt spun ribbons were carefully investigated. It was shown that in all cases soft magnetic properties can be significantly enhanced by applying 1-h annealing at characteristic temperatures T_op. This optimization annealing causes that permeability increases more than 15-times and magnetic losses (tangent of loss angle) achieves a minimum in relation to the as quenched state. Using structural examinations (X-ray and HRTEM) it was shown that for the Fe₇₅Cu₁Nb₂Si₁₃B₉ alloy the optimized microstructure corresponds to a nanocrystalline αFe(Si) phase whereas in other alloys to a relaxed amorphous phase free of iron nanograins. As a consequence of this fact the Fe₇₆Nb₂Si₁₃B₉ and Fe₇₅Ag₁Nb₂Si₁₃B₉ alloys show higher plasticity in comparison to the nanocrystalline Fe₇₅Cu₁Nb₂Si₁₃B₉ alloy. Temperatures of the first stage of crystallization, and related diffusion parameters were determined using measurements of resistivity versus temperature with different heating rates.     

Fe2+-Ni2+-NH3-NH4+-C2O42-H2O体系的沉淀配合平衡热力学

针对草酸盐配位共沉淀热分解还原法制备超细铁镍合金粉过程中Fe2+-Ni2+-NH3-NH4+-C2O42--H2O体系的溶液平衡建立热力学分析模型,并根据模型进行相关计算,揭示反应体系中各物质随pH值、氨及草酸浓度的变化关系。结果表明:溶液中的Fe主要以[Fe(C2O4)n]2 2n络合物形式存在,而铁氨络合物含量很低。当氨含量较低时,溶液中的Ni主要以[Ni(C2O4)n]2 2n存在;氨含量较高时,在酸性条件下,溶液中的Ni主要以[Ni(C2O4)n]2 2n存在,在碱性条件下,则主要以[Ni(NH3)n]2+存在。低pH值下,Ni的沉淀率较Fe的高,而高pH值下,Ni的沉淀率则较Fe的低。     

Thermodynamics and phase diagrams in the binary systems Na2O-SiO2, Na2O-GeO2, Na2O-B2O3, Li2O-B2O3, CaO-B2O3, SrO-B2O3, and BaO-B2O3

We applied our model to the enthalpy of mixing data of the binary systems Na₂O-SiO₂, Na₂O-GeO₂, Na₂O-B₂O₃, Li₂O-B₂O₃, CaO-B₂O₃, SrO-B₂O₃, and BaO-B₂O₃. The most stable composition in the liquid, that is where the enthalpy of mixing is most negative, is with a metal-oxygen ratio of 4 to 3, for monovalent metals (Na and Li) and 3 to 4 for divalent metals (Ba and Ca) in liquid silicates or borates. The same applies to the CaO-SiO₂, CaO-Al₂O₃, PbO-B₂O₃, PbO-SiO₂, ZnO-B₂O₃, and ZnO-SiO₂ systems. The oxygen to metal ratio, its constant value in various types of systems, reflects and describes the structure of the liquid. Using the analyzed enthalpies of mixing data and the available phase diagrams, we calculated the enthalpies of formation of the various binary compounds. The results are in excellent agreement with data in the literature that were obtained from direct solid-solid calorimetry.     

New Zr6CoAs2-type compounds: Y6CoBi2, Ho6CoBi2 and Tm6CoBi2

Results of a powder X-ray diffraction investigation of new ternary compounds are reported. The compounds Y₆CoBi₂ [a=0.8312(1) nm, c=0.4144(1) nm], Ho₆CoBi₂ [a=0.8246(2) nm, c=0.4095(1) nm], and Tm₆CoBi₂ [a=0.8155(2) nm, c=0.4066(1) nm] crystallize in the hexagonal Zr₆CoAs₂-type structure (space group P6b2m No. 189). The Zr₆CoAs₂-type structure is a superstructure of the Fe₂P-type structure.     

Zur Kenntnis von RbBa3Ca4Cu3V7O28

Single crystals of RbBa₃Ca₄Cu₃V₇O₂₈ were prepared above the melting point of the reaction mixture. It crystallizes with hexagonal symmetry, space group C_6V⁴-P6₃mc, a 11.1751, c 12.434 Å, Z = 2. RbBa₃Ca₄Cu₃V₇O₂₈ is the second member of a new structure type of the copper-oxovanadates. Ba²⁺ shows an unusual 12-fold coordination. The two calcium positions are coordinated by trigonal prisms and octahedra respectively. The copper coordination is characterized by a stretched square pyramid. The Cu²⁺ ions are outside the centre nearly in plane of the pyramids.

Zusammenfassung

Einkristalle von RbBa₃Ca₄Cu₃V₇O₂₈ wurden oberhalb des Schmelzpunktes der Reaktionsmischung erhalten. Die Verbindung kristallisiert hexagonal, Raumgruppe C_6V⁴-P6₃mc, a 11.1751, c 12.434 Å, Z = 2. RbBa₃Ca₄Cu₃V₇O₂₈ ist das zweite Beispiel für einen neuen Strukturtyp der Kupfer-Oxovanadate, mit 12-fach koordinierten Ba²⁺ -Ionen. Die zwei Calciumpositionen sind trigonal prismatisch bzw. oktaedrisch koordiniert. Die Koordination der Cu²⁺-Ionen ist durch eine gestreckte Pyramide charakterisiert. Cu²⁺ ist auβerhalb des Polyederzentrums nahezu in der quadratischen Fläche der Pyramide angeordnet.     

Al2O3-Sm2O3-CeO2电解质的性能（英文）

采用溶胶-凝胶法和低温燃烧技术制备Ce1-xSmxO2（x=0,0.1,0.2,0.3）和掺杂Sm和（2%-8%）Al2O3的二氧化铈;研究其合成、结构、致密化、导电性和热膨胀等性能,并利用XRD研究其结构和相组成。结果表明,于1300°C烧结球团,获得致密的陶瓷,于1250°C在Ce0.8Sm0.2O0.2中加入2%和4%的Al2O3以促进烧结。利用扫描电子显微镜观察烧结后球团的表面形貌,使用双探针交流阻抗谱研究总离子电导率。     

电弧喷涂制备Fe65Cr20Mo7B3.5SiMn1.5W3涂层

在Q235低碳钢板上利用电弧喷涂工艺进行喷涂,以制得Fe65Cr20Mo7B3.5SiMn1.5W3涂层。喷涂材料为自行配制的丝材,按照35%的填充率将配好的粉填充到U型不锈钢外皮中,经过多道拉拔、挤压工艺制成Φ2mm的粉芯丝材。采用X射线衍射仪、扫描电镜、能谱分析仪、透射电镜对涂层的物相和组织形貌及成分进行了表征;采用差示扫描量热仪、显微硬度仪等设备对涂层的热稳定性及显微硬度进行了检测和分析。试验结果表明:涂层组织形貌呈典型的层状组织结构,由变形良好的带状粒子相互搭接堆积而成。涂层含有50.63%的非晶相,同时含有纳米级的晶相。涂层组织均匀、结构致密、孔隙率低,并且涂层硬度高达1040.5HV0.3,属硬质涂层,具有良好的热稳定性。     

Synthesis and electrochemical properties of LiNi0.4Mn1.5Cr0.1O4 and Li4Ti5O12

Spinel compound LiNi_0.4Mn_1.5Cr_0.1O₄ (LNMCO) and Li₄Ti₅O₁₂ (LTO) were synthesized by the sol-gel method and the solid-state method, respectively. The particle sizes of the products LiNi_0.4Mn_1.5Cr_0.1O₄ and Li₄Ti₅O₁₂ were 0.5 to 2 um and 0.5 to 0.8 um, respectively. All samples exhibited excellent electrochemical properties. A LiNi_0.4Mn_1.5Cr_0.1O₄/Li₄Ti₅O₁₂ (LNMCO/LTO) cell was fabricated and was demonstrated to exhibit good electrochemical properties at the high current rate of 1 C. When the specific capacity was determined based on the mass of the LNMCO cathode, the LNMCO/LTO cell delivered 125 mAh g⁻¹ at 1 C and 77 mAh g⁻¹ at 5 C. The capacity retentions after 30 cycles were 94.4 % and 83.1 %, respectively.