Linear friction welding of Ti6Al4V: experiments and modelling

Linear friction welding of the Ti6Al4V alloy is studied. A new definition of the energy input rate is proposed, based on an integration over time of the in-plane force and velocity; a strong correlation with the upset rate is then found. The effective friction coefficient is estimated to be 0·5±0·1 for varying frequencies and amplitudes, with only a weak dependence on the processing conditions displayed. A model is proposed that accounts for both the conditioning and equilibrium stages of the process, which is shown to be in good agreement with the experimental data. The model is used to study the mechanism by which the flash is formed. A criterion is proposed by which the rippled nature of its morphology can be predicted.     

Al、Mo含量对铸造钛合金力学性能的影响

运用正交实验 ,考察了Al、Mo含量对Ti Al Mo 1Zr系铸造钛合金力学性能的影响。试验结果表明 :随Al、Mo含量提高 ,铸造合金的强度增加 ,塑性和冲击韧性降低 ,但Al、Mo的交互作用却使合金塑性提高 ,强度和冲击韧性降低     

凝胶成型法制备加氢催化剂载体的研究与工业化生产

采用凝胶成型法制备加氢催化剂载体，并进行了工业放大试验。通过BET、NH3-TPD、H2-TPR等表征手段及实际的加氢反应性能评价对凝胶成型法制备的载体及加氢催化剂与常规方法进行对比分析，结果表明，采用凝胶成型法所制得的载体及催化剂均具有较高的孔体积和比表面积、较低的堆密度，其机械强度可满足工业要求，总酸量及中强酸酸量得到提升，催化剂活性组分与载体强结合力得到削弱，金属利用率提高，应用性能明显优于传统方法制备的加氢催化剂载体。通过该方法完成了加氢催化剂载体的工业生产，所生产的载体应用于天津院THDS-3加氢精制催化剂取得了良好的工业应用效果。     

JOINING MECHANISMS OF β''''-Al2O3 CERAMIC AND PYREX GLASS TO Al MATRIX COMPOSITE

The bonding of β'-Al2O3 and pyrex glass to Al matrix composites by anodic bonding process is achieved. The microstructure of the bonded interface and the joining mechanisms are analyzed with scanning electron microscope (SEM), energy dispersive X-ray fluorescence spectrometer (EDX). It is observed that the bonding region across the interface consists of the metal layer, oxide transitional layer and the ceramic layer, with the transitional layer composed of surface region and sub-surface region. The bonding process can mainly be categorized into anodic bonding process and solid state diffusing process. The pile-up of the ions and its drift in the interface area are the main reasons for anode oxidation and joining of the interface. The temperature, voltage and the drift ions in the ceramic or glass during the bonding process are the essential conditions to solid state diffusing and oxide bonding at the interface. The voltages, temperature, pressure as well as the surface state are the main factors that influence the anodic bonding.     

Transmittance and cathodoluminescence of AlN ceramics sintered with Ca3Al2O6 as sintering additive

Aluminum nitride ceramics were prepared by sintering with 0–4.8 mass% of Ca₃Al₂O₆ (C₃A) as a sintering additive. The transmittance in the range of 260–550 nm increased with increasing amount of C₃A. The cathodoluminescence intensity attributed to oxygen-induced defects decreased with increasing amount of C₃A. From the results, the increase of the transmittance in the range of 260–550 nm was considered to be related to the decrease of the oxygen-induced defect density.     

均匀设计法分析制备过程对钴钼硫化物催化剂机械强度的影响

建立了CoMoP/Al2O3加氢精制催化剂机械强度及其可靠性在制备过程中的数学模型,采用均匀设计考察了浸渍、干燥、煅烧、硫化4个制备过程中,浸渍时间、干燥温度、干燥时间、煅烧温度、煅烧时间、硫化温度和硫化升温速率7个实验因子对催化剂强度均值、Weibull模量的影响,同时考察了这些因素对颗粒密度的影响。方差分析表明所有模型都是充足的。实验结果表明,硫化过程是影响催化剂强度均值的主要过程。在实验范围内提高硫化温度、降低硫化时的升温速率有利于提高催化剂的强度。影响催化剂Weibull模量的因素主要为各个制备过程的交互效应。要提高催化剂强度的可靠性就必须全面考虑催化剂制备的各个过程,特别是各个制备过程的交互效应。     

IF板与08Al板的成形性能研究

通过模拟成形性试验，对新型超深冲用IF钢板和传统冲压用08Al钢板的冲压成形性能进行了研究．结果表明：IF板的拉深性能、扩孔性能、胀形性能以及“拉深-胀形”复合性能等均优于08Al板，其中，扩孔性能和平面各向异性的改善最为显著；各项试验中，IF板的成形力普遍小于08Al板。     

Exchange and oxidation of CO on O-predosed Rh---Al2O3 and Rh---CeO2 catalysts

Exchange and oxidation of C¹⁶O were investigated at 450°C on ¹⁸O-predosed Rh and Pt catalysts supported on A1₂O₃, CeO₂ and CeO₂-Al₂O₃. In all cases, a rapid exchange of C¹⁶O with the surface can be observed. CO oxidation leads to C¹⁶O₂, C¹⁶O¹⁸O and C¹⁸O₂. Significant formation of C¹⁶O₂ is due to the relatively high ¹⁶O coverage in reaction resulting from the C¹⁶O exchange and from an exchange between O surface species and ¹⁶O internal atoms. Hydrogen is also formed via a water-gas shift reaction (CO + surface OH) in higher proportion on CeO₂-containing catalysts than on A1₂O₃. Chlorine inhibits all the reactions (exchange, oxidation and WGS) and particularly the internal exchange.     

助剂对Pd/树脂醚化催化剂催化性能的影响 Ⅰ.铝助剂的影响

研究了不同助剂对Ｐｄ／树脂醚化催化剂在临氢条件下对催化裂化汽油Ｃ５馏份与甲醇和Ｈ２反应的催化性能的影响。结果表明，在Ｐｄ／树脂醚化催化剂中引入Ｚｒ、Ｔｉ、Ｂ、Ｓｎ和Ａｌ等助剂后，都能改善催化剂的醚化、双键异构和二烯烃选择性加氢活性，其中以Ａｌ、Ｓｎ为最好。Ａｌ助剂的体积质量和负载方式对Ｐｄ－Ａｌ／树脂醚化催化剂的活性有影响。ＢＥＴ方法和Ｘ－射线荧光光谱分析（ＸＦＳＡ）表明，Ａｌ助剂对Ｐｄ－Ａｌ／树脂醚化催化剂的表面积、孔结构和Ｐｄ离子交换量影响较小。