Ag/Cu/Fe系层状复合材料的制备及性能

采用新工艺制备了Ag／Cu／Fe系层状复合材料。研究了在不同变形量、热处理温度和一定保温时间下材料的电学和力学性能的变化,得出材料的最佳热处理条件,并探讨了变形过程中性能变化的机理。     

TiAl/Ag-Cu-Ni-Li/35 CrMo感应钎焊接头的组织特征

利用扫描电镜、电子探针及能谱分析等方法,对TiAl／Ag-Cu-Ni-Li／35CrMo感应钎焊的接头组织进行了研究。结果表明,钎焊焊缝沿圆柱试件径向出现宽、窄两反应区：钎焊试件外侧为宽反应区,内侧为窄反应区．两区界线明显。900℃保温5min时的钎焊接头组织结构为：TiAl／TiAl与钎缝间的扩散层／富Ag、Cu相／Ti(Cu,Al)2相／富Ag相／AlM2Ti相(M代表Fe,Cu,Ni)／钎缝与35CrMo间的扩散层／35CrMo。靠近TiAl侧的反应层组织形态依次为等轴细晶和Ti(Cu,A1)2相柱状晶,Ti(Cu,Al)2相柱状晶与TiAl母材存在一定的位向关系。     

Cu基材料作焊接过渡层TA1/Q345复合板接头的组织与性能

以Cu-Ag-Mo药芯焊丝为焊接中间层过渡材料,对TA1/Q345双金属层状复合板进行熔焊试验。利用SEM、EDS和XRD等分析方法对接头元素分布、相组成及组织构成进行了微观分析,并进行了焊缝区显微硬度测试。结果表明:钛焊缝中,微量的Fe向上扩散形成了少量的金属间化合物Ti Fe,在拉伸应力的作用下产生了裂纹,但在过渡层中的Ag元素具有很好的流动性,填补了裂纹,阻碍了裂纹的扩展;过渡层Mo元素与扩散Ti形成了连续固溶体,降低了过渡区中扩散Ti的含量,控制了Ti、Fe金属间化合物的生成;焊缝区的显微硬度值整体呈下降趋势,但其中钛焊缝与过渡层界面处的硬度值高达475 HV0.1,该区域的主要相为Ti Cu和Ti2Cu,降低了焊接接头塑韧性。     

粉末冶金法制备Cu/Ag(Invar)复合材料的显微组织与性能（英文）

采用球磨制得的Ag(Invar)复合粉体制备Cu/Ag(Invar)复合材料。研究烧结及形变热处理后复合材料的显微组织结构与性能。结果表明,在球磨过程中,微锻造焊合与加工硬化断裂共同作用导致Ag(Invar)粉体的平均颗粒尺寸先急剧增大,再快速降低,最后趋于稳定。相对于Cu/Invar复合材料,Cu/Ag(Invar)复合材料的烧结性能大大提高,其中的气孔小而少。形变热处理后,该复合材料近乎完全致密,具有最佳的相成分与元素分布,更重要的是,该复合材料中的Cu及Invar合金均呈三维网络状连续分布。Cu/Invar界面扩散被Ag阻挡层有效抑制,使Cu/Ag(Invar)复合材料的力学及热学性能均有明显提高。     

Ag/Cu钎焊复合带材轧制和退火研究

利用Ag-28Cu合金钎焊复合制备Ag/Cu复合材料,经轧制加工成复合带材。研究轧制变形和扩散退火对复合界面形貌、界面组织和性能的影响,以及界面元素扩散特征。结果表明,随着轧制变形量增加,Cu、Ag-28Cu和Ag发生协调变形,复合界面由波浪形,转变成锯齿状,最后Cu层整体向Ag层倾斜。随着加工率增加,Cu层硬度逐渐降低,Ag-28Cu层硬度显著升高,Ag层硬度不变。随着退火温度增加,界面组织逐渐长大粗化,复合层宽度增加。界面原子扩散行为主要是Cu原子向Ag中发生扩散,退火温度增加时,Ag-28Cu层中Cu原子向Ag侧逐渐减少,Ag层中的Cu原子含量增加,Cu和Ag层硬度没有发生变化,而Ag-28Cu层硬度逐渐降低。     

SnAgCu/Cu和SnPb/Cu界面热-剪切循环条件下化合物的生长行为

对热剪切循环条件下Sn-3.5Ag-0.5Cu/Cu和Sn-Pb/Cu界面上原子扩散和化合物的生长行为进行了研究。结果表明:再流焊后,在两界面上均形成一种Cu6Sn5化合物;随着热剪切循环周数的增加,两界面上化合物的形态均从扇贝状向层状生长,其厚度随循环周数的增加而增加,且生长基本遵循抛物线规律,说明Cu原子的扩散控制了Cu6Sn5化合物的生长。界面近域的钎料内,颗粒状的Ag3Sn聚集长大成块状。     

合金元素对彩金颜色及加工性能的影响

以Au－Ag－Cu系为基础,对影响合金的颜色及加工性能的因素,如成分、热处理制度等做了探讨。结果表明,Ag／Cu配比是影响颜色的主要因素,合金的加工性随相对Ag含量的减少而变差,热处理制度随合金成分的不同而变化。     

镁/铝层状复合材料的扩散连接制备及界面特性

采用扩散连接制备了镁/铝层状复合材料,进而采用热处理改善界面结合性能,最后利用纳米压痕技术初步研究了复合材料的界面结合状况。结果表明,采用400℃/30MPa/10min、400℃/40MPa/10min和400℃/30MPa/20min3种条件均可获得连接较好的层状复合材料,但400℃/30MPa/10min条件下扩散层不明显;利用热处理可以改善界面结合状况,对于扩散层明显的复合材料,热处理可以大大增加扩散层厚度;扩散层的纳米硬度比基体高约3倍,弹性模量介于镁合金的与铝合金的之间。     

液固相复合-轧制铜包钢线的组织性能及界面冶金行为

以液固相复合-轧制工艺生产的铜包钢线为研究对象,研究了在特定工艺条件下铜／钢界面的组织组成及其界面区的冶金行为。经金相组织观察,铜、钢晶粒在界面处直接接触,界面呈极细微的凹凸不平的状态,经冷轧后,铜、钢晶粒在界面处互相咬合,且铜与钢的变形随着变形量的增大而趋于均匀。通过对界面区的成分进行能谱分析表明,Cu,Fe原子间发生了互扩散,形成了Fe／Cu的固溶体,其中Fe向Cu扩散量明显高于Cu向Fe的扩散量,测试界面结合强度表明,铜包钢线的初结合界面剪切强度可达80-95 MPa,轧制变形后该强度可提高3％-5％。     

扩散热处理对316L不锈钢表面钯／铁薄膜形貌和相组成的影响

采用真空电弧离子镀工艺，在316L不锈钢表面沉积钯，铁（Pd／Fe）合金薄膜并进行真空扩散热处理，观察扩散热处理工艺对Pd／Fe薄膜的形貌和相组成的影响。结果表明：采用真空电弧离子镀工艺，可在316L不锈钢表面沉积均匀的Pd／Fe膜；扩散热处理工艺对Pd／Fe膜的形貌和相组成有显著影响。经900℃保温1h处理后，Pd膜与Fe膜间互扩散形成一定量的Pd-Fe合金相；随着热处理温度升高，Pd,Fe膜层向316L基体扩散的距离增大，同时基体中的Cr，Ni向外扩散的量也增多。     

Influence of Nb Diffusion Layer on Superconductivity of MgB2/Nb/Cu Wires

采用原位法粉末装管工艺(in-situ PIT),以Nb/Cu复合管作为包套材料制备了MgB2超导线材并且在氩气保护气氛中,不同温度条件下保温2h进行成相热处理。分别采用电阻-温度测试、磁矩转变测试、临界传输电流测试以及Nb-MgB2界面磁光研究等分析手段进行研究。结果表明:当热处理温度高于750℃时,在MgB2超导芯丝和Nb阻隔层之间形成一个扩散层,该扩散层的存在阻碍了电流的传输,从而导致在磁测法测试中可以检测到超导相存在,而在传输法测试中无法看到超导传输现象。说明采用Nb作为MgB2超导线带材的扩散阻隔层时其热处理温度不能高于750℃。     

热处理对C/C-SiC接头连接强度的影响

C纤维增强C和SiC双基复合材料(C/C-SiC)的连接是其能否得到广泛应用的关键技术之一。采用硼改性酚醛树脂以及B4C和SiO2填料通过反应成形连接工艺连接C/C-SiC,研究热处理温度(300～1000℃)对连接件强度保留率的影响。结果表明,随着热处理温度的升高,强度保留率先降低,在800℃时达到最低值80.6%,然后随着温度进一步升高,强度保留率又升高,在1000℃时达到88.1%,表明连接件具有较好的耐热性能。随着热处理温度的升高,连接层相组成发生变化。连接件经过1000℃处理30min后,连接层由B4C、SiO2和玻璃碳以及无定型B2O3组成,C、Si、O和B元素分布都较为均匀,并在界面处发生了扩散,连接件断裂方式为混合断裂。     

Preparation and H^＋ response mechanism of W/WO3 pH electrode by sol-gel method

1 INTRODUCTION Acidityis one of the most i mportant parame- ters in aqueous samples . Although the glass elec- trodeis byfar the most commonly used pHsensor , li mitations of the glass electrode ,such as acid and alkaline error , high i mpedance , high temperature instability and mechanical fragility restrict its fur- ther application to pH determination in the wider range[1]. Therefore ,the researchinterest has been directed toward the development of alternatives to conventional glass el…     

Heat treatment effect on electrochemical properties of spinel Li4Ti5O12

Anode material Li4Ti5O12 was prepared at 800℃ by a solid-state reaction, followed by heat-treatment at 600℃ for different times （0, 2, 8, and 12 h）. The effects of heat-treatment time on the particle morphology, rate-capability, and electrode kinetic process of the Li4Ti5O12 electrode, and on the lithium ion diffusion coefficient inside the Li4Ti5O12 electrode were investigated. Proper heat treatment could smoothen the particle surface of Li4Ti5O12 particles and increase the rate-capability of the electrode. Overlong heat treatment might cause particle aggregation and hence result in a poor electrode kinetic process. A sample with 8 h of heat treatment showed the best rate-capability and the lowest electrode reaction resistance. Heat treatment for 2-8 h does not significantly change the lithium ion diffusion coefficient inside the Li4Ti5O12 electrode, whereas, 12-h treatment results in a lower lithium ion diffusion coefficient.     

Effects of isothermal heat treatment on microstructural evolution of semisolid Al-4Cu-Mg alloy

The authors investigated the effects of the isothermal heat-treatment conditions on the microstructural evolution and composition distribution of semisolid Al-4Cu-Mg alloy during isothermal heat treatment. The experimental results show that the microstructural evolution and composition distribution of semisolid Al-4Cu-Mg alloy are controlled by atom diffusion during the isothermal heat treatment process. Grain growth and spheroidization were promoted with the increase of the isothermal temperature and/or the holding time. Moreover, the higher the isothermal temperature, or the longer the holding time, the more segregation constituent elements occurred to the grain boundaries. The low melting structure at grain boundary is greatly affected by Cu. The microstructural evolution in the isothermal heat-treatment process is as follows: recovery, recrystallization, fragmentation, spheroidization, and coarsening. Such fragmentation, spheroidization, and grain growth of coalescence and Ostwald ripening are involved as main mechanisms in the isothermal heat-treatment process.     

钛沉积工艺制备TiN/cBN和TiC/金钢石涂层颗粒(英文)

用钛熔盐沉积及热处理工艺分别制备碳化钛涂覆的立方碳化硼颗粒(TiN/cBN)及碳化钛涂覆的金刚石颗粒(TiC/金刚石)。将cBN或金刚石颗粒分别与钛粉和KCl、NaCl和K2TiF6熔盐混合。将所得混合物在Ar气氛中加热至900°C,然后在H2气氛中于1000°C进行热处理。采用扫描电镜、X射线衍射和聚焦离子束技术对所制得颗粒进行表征。结果表明:cBN和金刚石颗粒表面已覆盖了纳米钛层。对Ti/cBN和TiC/金刚石涂层颗粒进行热处理后,颗粒表面沉积的Ti层与cBN和金刚石颗粒发生了原位化学反应,分别转化为钛化合物TiN和TiC。     

SiCp/ZL108复合材料的时效行为

液态搅拌法制备了SiCp/ZL108复合材料,试验研究了该复合材料固溶处理后的时效行为。复合材料ZL108-20vol%SiCp在515℃固溶处理后,180℃时效,3h～7h达到时效峰值,硬度HBS167.6。自然时效2d～7d后硬度达到峰值硬度HBS134.5。复合材料SiCp/ZL108固溶处理后人工时效可以大幅提高其性能水平。     

Au/NiCr/Ta和Au/NiCr多层金属膜的划痕特征载荷

采用摩擦力和声发射两种模式同时监测的划痕法研究了Au/NiCr/Ta和Au/NiCr多层金属薄膜的临界载荷Lc，并与TiN硬质薄膜进行了对比。实验结果表明：摩擦力和声发射模式均能反映出压头进入不同金属膜层时的变化，在单一金属薄膜层中两者均无大的变化，对应实验范围内不同的沉积温度，拐点特征载荷值基本不受其影响，而主要取决于多层膜的层厚和层数。     

Effect of annealing on the morphology evolution and densification of LiMn2O4 film from chitosan-containing solution

Dense LiMn₂O₄ films deposited on a Pt-coated silicon substrate were obtained by annealing the deposited Li–Mn–O-chitosan films under a two-stage heat-treatment procedure. It was demonstrated that the heat-treatment at 300 °C plays an important role in the subsequent densification of LiMn₂O₄ films. This is attributed to the formation and rearrangement of the nano-sized LiMn₂O₄ crystallites. The surface morphology of the calcined Li–Mn–O-chitosan films was highly related to the annealing temperature. Ridge-like bumps formed on the surface of the films after being heated at 200 °C for 1 h. With calcination at 400 °C or higher, the surface morphology turned into a wrinkle-like microstructure. This morphology transformation is ascribed to the flowing characteristics of the Li–Mn–O-chitosan films during heat-treatment and subsequent thermal decomposition of the precursor at higher temperatures. Moreover, the electrochemical tests showed that the 700 °C-annealed LiMn₂O₄ film possesses the highest discharge capacity of 56.3 μA h/(cm² μm) and best capacity retention of 90.7% after 50 charge/discharge cycles of all annealed films.