铜－铌复合体冷加工后抗拉强度和导电性能的研究

对铜中添加铌的不同组份Ｃｕ－Ｎｂ铸锭的冷加工性及经不同冷拉拔比（ε）Ｃｕ－Ｎｂ复合体的抗拉强度（σｂ、σ０．２）与导电性能等方面进行了研究。试验结果表明：在含Ｎｂ量＜２０Ｖｏｌ．％的Ｃｕ－Ｎｂ铸锭，其塑性优良，可进行冷加工；当冷拉拔比为６时，Ｃｕ－１８Ｖｏｌ．％Ｎｂ和Ｃｕ－２０ｖｏｌ．％Ｎｂ两种复合体的极限强度与屈服强度分别达７００～８００ＭＰａ和６００～７００ＭＰａ；其导电率约为无氧铜的２／３。用金相显微镜观察了Ｃｕ－Ｎｂ复合体的显微组织。文中还对与Ｃｕ－Ｎｂ复合材料的性能有关的问题进行了讨论。     

带Nb膜中间层的Cu/α-Al2O3的扩散焊接

采用扫描和透射电镜、能谱分析、Ｘ射线衍射和４点弯曲试验研究了Ｎｂ膜中间层对单晶Ｃｕ与单晶α－Ａｌ２Ｏ３的扩散焊接特怀以及接头组织和性能的影响。结果表明,通过电子不蒸镀获得的多晶Ｎｂ膜中间层扩散焊后具有结构组织,其密排面（１１０）平行于Ａｌ２Ｏ３的（０００１）基面,Ｎｂ膜中间层的加入显著提高了Ｃｕ／Ａｌ２Ｏ３扩散焊接头的断裂能量,而扩散焊接温度可以与无Ｎｂ膜中间层时保持不变,带Ｎｂ膜中间层的Ｃｕ／Ａ     

新型Cu／Pd和合电触点材料

研究制备Ｃｕ／Ｐｄ２５、Ｃｕ／Ｐｄ３０、Ｃｕ／Ｐｄ４０和Ｃｕ／Ｐｄ６０（ｗｔ％）复合材料并测量它们的力学及电学性能，利用金相显微镜和扫描电镜观察了复合 组织结构，对不同Ｐｄ含量的Ｃｕ／Ｐｄ复合材料的性能进行比较。这类新型Ｃｕ／Ｐｄ复合材料显示出优异的可加工性、适中的硬度和非常高的电导率，是目前世界上最好的直流触点材料之一。     

Cu/Al_2O_3扩散焊接头界面晶体位向关系对断裂能量的影响

以单晶α－Ａｌ２Ｏ３陶瓷（蓝宝石）和单晶 Ｃｕ为母材,采用真空扩散焊接获得具有两种不同的界面晶体位向关系的Ｃｕ／Ａｌ２Ｏ３扩散焊接头以及带 Ｎｂ膜中间层的 Ｃｕ／Ｎｂ／Ａｌ２Ｏ３扩散焊接头,研究了界面晶体位向关系对接头断裂能量的影响。结果表明,陶瓷－金属界面的晶体位向关系影响界面粘合功（Ｗａｄ）和断裂过程中金属侧所消耗的塑性变形功（Ｗｐ）,从而显著影响接头的断裂能量。界面位向关系为（１００）［０１１］Ｃｕ／／（０００１）［１１２０］Ａｌ２Ｏ３的 Ｃｕ／Ａｌ２Ｏ３接头断裂能量值最低,而具有相同位向关系的带 Ｎｂ膜中间层的 Ｃｕ／Ｎｂ／Ａｌ２Ｏ３接头的断裂能量值则最高。     

Cu/Al2O3扩散焊接头界面晶体位向关系对断裂能量的影响

以单晶α－Ａ１２Ｏ３陶瓷（蓝宝石）和单晶Ｃｕ为母材,采用真空扩散焊接获得具有两种不同的界面晶体位向关系的Ｃｕ／Ａ１２Ｏ３护散焊接头以及带Ｎｂ膜中间层的Ｃｕ／Ｎｂ／Ａ１２Ｏ３护散焊接头,研究了界面晶体位向关系对接头断裂能量的影响,响接头的断裂能量,界面位向关系为（１００）「０１１」ｃｕ｜｜（０００１）「１１２０」Ａ１２Ｏ３的Ｃｕ／Ａ１２Ｏ３接头断裂能量值最代,而具有相同位向关系的带Ｎｂ膜中间层的Ｃｕ     

球磨粉末反应热压法合成铌/硅化铌复合材料

Ｎｂ/Ｓｉ二元合金基复合材料是一种很有前途的高温结构材料 ,在这种双相复合材料之中固溶铌提供室温韧性而Ｎｂ5Ｓｉ3 提供高温强度 ,这种复合材料在高温下具有高度的热力学稳定性和显微组织稳定性。日本超高温材料研究所等单位研究了利用球磨粉末的反应热压法制取铌 /硅化铌复合材料 ,并研究评价其显微组织和力学性能。在本研究中 ,球磨过程是作为一种预处理方法 ,用来提高随后的反应烧结效果。用来实验研究的粉末采用了元素铌粉 (纯度 99 9% ,粒度 <32 5目 ) ,半导体级硅 (粒度 <30 0目 ) ,按照Ｎｂ 3 5 %Ｓｉ、Ｎｂ 6 %Ｓｉ、Ｎｂ 10 %…     

Cu／Pd复合材料的组织特征及性能研究

研究制造几种不同结构的Ｃｕ／Ｐｄ复合材料,测试其电学及力学性能,用金相显微镜及扫描电子显微镜分析它们的组织特征,比较不同方法制造的Ｃｕ／Ｐｄ复合材料的组织及性能。     

在600－800℃低氧压下Co－Nb合金的氧化

研究了含１５与３０ｗｔ％Ｎｂ的两种Ｃｏ－Ｎｂ合金在６００－８００℃低氧压Ｆ的氧化性能选择的氧压低于相应温度的氧化钴分解压，由Ｈ２－ＣＯ２混合气获得，在６００℃为１０－２４ａｔｍ，而７００与８００℃为１０－２０ａｔｍ．两种合金在６００与７００℃氧化结果仅产生由α－ＣＯ与氧化铌（ＮｂＯ２与Ｎｂ２Ｏ５）混合物组成的内氧化带在７００℃尚可能生成双元氧化物ＣＯＮｂ２Ｏ６在内氧化带界而无贫Ｎｂ层可见．两会金，尤其是Ｃｏ－３０Ｎｂ在８００℃时发生了由内氧化向外氧化的转变，伴随有贫Ｎｂ的单相区出现于合金的表层．从Ｃｏ中Ｎｂ的溶解度很低和合金与氧化膜显微组织的特点等角度详细讨论了合金的腐蚀机制．     

雾化粉末形状对Fe—Si—Al系压粉磁心磁特性的影响

最近发现Ｆｅ Ｓｉ Ｂ Ｎｂ Ｃｕ系铸造非晶态合金棒(直径约为 0 5ｍｍ) ,通过退火晶化可形成由纳米级ｂｃｃ-Ｆｅ晶粒与其周围残留非晶相所组成的显微组织 ,具有良好的软磁性能。新近研究了利用铜模铸造法生产的Ｆｅ Ｓｉ Ｂ Ｎｂ Ｃｕ系非晶态合金棒的部分晶化组织与其磁性能之间的关系。研究时采用了纯金属铁、铌、铜和纯硅和晶体硼作原料配成的混合料 ,在氩气氛中电弧熔炼制得Ｆｅ95-ｘ -ｙＳｉｘＢｙＮｂ4Ｃｕ1 (原子百分比 )多元金合锭。该合金锭重熔后用铜模铸造法制成不同直径 (≤ 2ｍｍ)的合金棒。同时也利用熔体旋淬法制备合金…     

Al65Cu20Cr15准晶颗粒／铝基复合材料中二十面体准晶扩散相变

用ＪＣＸＡ－７３３型电子探针,Ｈ－８００型透射电镜、Ｄ／ｍａｘ－ⅢＡ型Ｘ射线衍射仪等研究了Ａｌ６５Ｃｕ２０Ｃｒ１５准晶颗粒／铝基复合材料中的准晶颗粒在热压过程中扩散相变。     

Sn-0.7Cu-xNb复合钎料微观组织和力学性能

文中主要研究了纳米Nb颗粒对Sn-0.7Cu基复合钎料显微组织和力学性能的影响。结果表明,添加纳米Nb颗粒细化了Sn-0.7Cu复合钎料微观组织,提高了Sn-0.7Cu复合钎料的抗拉强度。当Nb含量为0.12%时抗拉强度达最大值25.36 MPa,但此时钎料的断后伸长率有所降低。Sn-0.7Cu-x Nb复合钎料的断裂模式均为塑性断裂,随Nb含量的增加,Sn-0.7Cu基复合钎料断口表面的韧窝尺寸逐渐变小,表明微量的纳米Nb可以抑制合金内Cu 6 Sn 5金属间化合物的长大。     

Tribological properties of Cu-based composites with S-doped NbSe_2

n this study, S-doped Nb Se_2(NbS_(0.2)Se_(1.8)) powders were fabricated, and the corresponding Cu-based composites(Cu/Nb S_(0.2)Se_(1.8)) were obtained by powder metallurgy technique. The phase compositions, physical, and tribological properties of Cu-based composites were investigated systematically. The results show that Cu matrix reacts with Nb S_(0.2)Se_(1.8)to produce Cu_2 Se and Cu_(0.38) Nb S_(0.2)Se_(1.8)during sintering process, which influences the physical and tribological properties of Cu-based composites significantly. Specially, with Nb S_(0.2)Se_(1.8)content increasing, the density of Cu/Nb S_(0.2)Se_(1.8)composites decreases, and the hardness increases firstly and then decreases, while the electric resistivity increases slightly. In addition, the incorporation of Nb S_(0.2)Se_(1.8)enhances the tribological properties of Cu greatly, which is attributed to the lubricating effect of Cu_(0.38) Nb S_(0.2)Se_(1.8)and the reinforcement effect of Cu_2 Se. In particular, when the content of Nb S_(0.2)Se_(1.8)is 6 wt%, the Cu-based composite has the best tribological properties.     

DIFFUSION REACTIONS BETWEEN Cu AND NbTi-ALLOY

Diffusion reaction of superconductig composite NbTi/Cu assembled both mechanicallyand metallurgically,diffusion couples Ti/Cu and Nb/Cu have/been studied by means ofEPMA.The results indicate that the initial interface state of thecomposite NbTi/Cu significantly affects the forming process of intermetallic compounds atthe interface.In comparison with the metallurgically bound composite,the intermetallic com-pounds forms at a higher temperature in mechanically bound one.Therefore.the mechanicalhinding process is beneficial to the production of NbTi/Cu superconducting composite.No intermetallic compounds have been observed in Nb/Cu system.The morphology ofintermetallic phases and the sequence in which they form in Ti/Cu system are somewhatdifferent from that in NbTi/Cu.The relationship between the thickness of compound layerand annealing time obeys the rule of y~(1.5) ∝ t.     

Cu与NbTi之间扩散反应的研究

采用电子探针微分析术研究了机械复合和冶金复合两种界面状态的Nb-Ti/Cu复合超导线,以及Nb-Ti/Cu,Ti/Cu和Nb/Cu偶的扩散反应过程.结果表明,原始组件的界面状态对Nb-Ti/Cu间金属间化合物的生成有明显的影响.机械复合组件较冶金复合组件能承受更高的热处理温度而不致生成金属间化合物.Ti与Cu之间反应生成化合物的次序与形态及NbTi与Cu之间不同.Ti/Cu间生成化合物的厚度y与时间t关系遵循y~(1.5-t)的规律.     

Meso-Scale Modeling the Orientation and Interface Stability of Cu/Nb-Layered Composites by Rolling

Metallic-based multilayered nanocomposites are recognized for their increased plastic flow resistance and indentation hardness, increased ductility, improved radiation damage resistance, improved electrical and magnetic properties, and enhanced fatigue failure resistance compared to conventional metallic materials. One of the ways in which these classes of materials are manufactured is through accumulated roll bonding where the material is produced by several rolling and heat-treatment steps during which the layer thickness is reduced through severe plastic deformation. A single rolling pass of the accumulated roll bonding process in which a Cu/Nb-layered composite with an initial average layer thickness of 24 μm subjected to a 50% height reduction is modeled. A single-crystal model based upon thermally activated dislocation motion is used. Nanohardness tests for both the Cu and Nb layers are used to help initialize the model for each of the two materials. Electron backscatter diffraction (EBSD) data of the heat-treated material is used to characterize the initial state of the composite and to produce 40 combined morphological and crystallographic numerical model realizations of the material. The results suggest very good agreement between the predicted and experimental textures for both the materials. Highly oriented microstructure develops during severe plastic rolling deformation of Cu/Nb nanocomposites. The deformation textures significantly deviate from those expected when rolling Cu or Nb alone, and the Cu/Nb interfaces do not correspond to those with the lowest possible formation energies. We study the interfacial stability of specific Cu/Nb bicrystal configurations under rolling conditions using a finite-element crystal plasticity model. Specifically, we examine how slip activity and lattice reorientation are affected by the kinematic constraint imposed by the interface. Our results show that for certain configurations the slip activity and lattice rotation of the individual crystallites display some sensitivity to the kinematic constraint, yet the overall stability of a given bicrystal can be predicted by the stability of the individual single-crystal orientations. Future work will account for the influence of the bimetal interface on the interface stability and development of enhanced properties.     

Effect of W/Cu composite filler metals on the microstructure and mechanical properties of laser welded pure niobium/304 stainless steel joint

Cracking in a laser weld of niobium to stainless steel occurred due to the formation of brittle, continuously distributed Nb-Fe intermetallic compounds. A crack-free joint, which had a tensile strength of 147 MPa, was obtained by using the W/Cu composite filler metals. To determine the reasons for cracking in the Nb/SS joint and the function of the W/Cu composite filler metals on the improvement of the cracking resistance of the Nb/W/Cu/SS joint, the microstructures of the joints were studied by optical microscopy, scanning electron microscopy and X-ray diffraction. The cracking susceptibilities of the joints were evaluated with microhardness test on the cross section of the Nb/W/Cu/SS joint. The results showed that the Nb/W/Cu/SS joint was characterized by various solid solution. The formation of solid solution reduced the cracking susceptibility of the joint.     

Size-induced enhanced mechanical properties of nanocomposite copper/niobium wires: nanoindentation study

The effect of microstructure dimension δ on plasticity of high strength multifilamentary nanocomposite copper/niobium wires was studied by nanoindentation. Two structures were tested: a Cu matrix containing Nb filaments and a Cu matrix containing Nb tubes filled with Cu. For δ>10 μm, no size effect on the composite hardness is observed. In the 1–10 μm range, a strong increase in hardness indicates a change in plasticity mechanism, attributed to the classical Hall–Petch grain size strengthening. In the nanometre range, the hardness of the nanocomposite Cu/Nb regions exceeds that of nanocrystalline Cu or Nb, reaching 5.8 GPa for the finest conductors. The observed size effect on the plasticity of Cu/Nb nanostructures added to the dislocation barrier role of Cu/Nb interfaces confirms previous analyses based on the occurrence of a single dislocation regime at nanometre scale associated with impenetrable Cu/Nb interfaces.     

采用Ag-Cu-In-Ti钎料真空钎焊SiO2f/SiO2复合陶瓷与铌

设计了Ag-(15~26)Cu-(13~20)In-(3.1~6.9)Ti活性钎料,分别在780℃/20 min,780℃/40 min和800℃/10 min三种参数下实现了SiO_2f/SiO₂复合材料与铌的连接,分析了接头微观组织,测试了接头室温抗剪强度.其中800℃/10 min钎焊参数下的接头平均抗剪强度最高,达到21.6 MPa;微观分析结果表明,接头中靠近SiO_2f/SiO₂母材界面处形成了厚度约为2μm的连续扩散反应层,靠近铌的界面钎料与母材也形成了良好的结合.该钎焊参数下接头界面物相依次为:SiO_2f/SiO₂→TiO+TiSi₂→TiO+Cu₃Ti→Ag(s, s)+Ag₃In+Cu(s, s)→Nb.     

超高强度及塑性的钨丝增强ZrTiCuNiBeNb金属玻璃复合材料

采用渗流铸造工艺制备了钨丝增强ZrTiCuNiBeNb金属玻璃复合材料,利用X射线衍射、扫描电镜、压缩力学试验机研究了复合材料的相组成、界面结构及室温力学性能。结果表明,钨丝增强ZrTiCuNiBeNb金属玻璃复合材料界面非常清晰光洁,证明了微量Nb元素的加入能够有效地抑制界面反应的发生;含钨丝体积分数60%的复合材料具有超高的强度(断裂强度3695MPa)和室温塑性(塑性应变25.3%)。优化的界面结构和钨丝体积分数是产生这种现象的原因。     

高强高导Cu-Nb微观复合材料的界面结构

通过集束拉拔技术获得了高强度高电导Cu-Nb微观复合材料,采用SEM及EDS观察分析了4次复合过程中内部Nb芯丝和Cu层的微观形貌变化,Cu/Nb界面的互扩散行为;对不同复合条件下的挤压、拉拔样品,通过XRD测试,表征了芯丝和基体的晶体取向的演变规律;通过HRTEM和反傅里叶变换研究了Cu/Nb的界面结构和晶体学位向关系。研究表明,在极塑性变形条件下,Cu/Nb界面在3次复合出现明显扩散,Cu、Nb逐渐形成丝织构取向,界面存在典型的(111)_(Cu)//(110)_(Nb)取向关系,晶面夹角为18.7°,每6个(111)Cu晶面出现1个晶面错配。