一种新型板件连接

TOX板件冲压连接工艺是一种新的板件连接技术。作者对TOX板件冲压连接技术进行了应用研究，并取得了一些经验。主要介绍一种板件连接技术－板件冲连接工艺，较详细地叙述了其原理、应用范围及工艺要点。     

MB8镁合金薄板的搅拌摩擦焊

针对我国航空航天工业常用的MB8镁合金。采用搅拌摩擦焊工艺进行焊接，对其焊缝的成形特点、组织特征和力学性能进行分析。结果表明，采用搅拌摩擦焊焊接镁合金效果良好。     

Material flow and microstructure in the friction stir butt welds of the same and dissimilar aluminum alloys

The material flow and microstructural evolution in the friction stir welds of a 6061-Al alloy to itself and of a 6061-Al alloy to 2024-Al alloy plates of 12.7 mm in thickness were studied under different welding conditions. The results showed that plastic deformation, flow, and mechanical mixing of the material exhibit distinct asymmetry characteristics at both sides of the same and dissimilar welds. The microstructure in dissimilar 6061-Al/2024-Al welds is significantly different from that in the welds of a 6061-Al alloy to itself. Vortex-like structures featured by the concentric flow lines for a weld of 6061-Al alloy to itself, and alternative lamellae with different alloy constituents for a weld of 6061-Al to 2024-Al alloy, are attributed to the stirring action of the threaded tool, in situ extrusion, and traverse motion along the welding direction. The mutual mixing in the dissimilar metal welds is intimate and far from complete. However, the bonding between the two Al-alloys is clearly complete. Three different regions in the nugget zone of dissimilar 6061-Al/2024-Al welds are classified by the mechanically mixed region (MMR) characterized by the relatively dispersed particles of different alloy constituents, the stirring-induced plastic flow region (SPFR) consisting of alternative vortex-like lamellae of the two Al-alloys, and the unmixed region (UMR) consisting of fine equiaxed grains of the 6061-Al alloy. Within all of these three regions, the material is able to withstand a very high degree of plastic deformation due to the presence of dynamic recovery or recrystallization of the microstructure. The degree of material mixing, the thickness of the deformed Al-alloy lamellae, and the material flow patterns depend on the related positions in the nugget zone and the processing parameters. Distinct fluctuations of hardness are found to correspond to the microstructural changes throughout the nugget zone of dissimilar welds.     

氮化硅基陶瓷连接技术的研究进展

陶瓷连接技术是结构陶瓷实用化的有效手段，焊料成分对连接体的性能具有决定性作用。本文主要从焊料成分选择的角度，总结了氮化硅基陶瓷连接技术的发展现状；并重点讨论了陶瓷／玻璃复合焊料在β-Sialon陶瓷连接中的应用。     

Electric field assisted solid-state interfacial joining of TaC-HfC ceramics without filler

The application of ultra-high-temperature ceramics (UHTCs) demands effective ways of joining in overcoming the problems associated with the fabrication of complex-shaped components. In this study, we choose to investigate a new method of rapidly joining pre-sintered TaC and HfC ceramics without any filler material using the spark plasma sintering (SPS) technique. A well-bonded TaC–HfC interface was observed with no apparent cracking and porosity at the joint. The joining mechanisms were predominantly driven by solid-state diffusion and localized plastic deformation. The nanomechanical properties of the TaC-HfC joint are better than the HfC while comparable to that of the TaC. High-load indentation (up to 200 N) results suggest that the TaC–HfC interface is stronger than the parent UHTCs with no crack propagating at the interface. Upon comparison with the parent UHTCs, the damaged area and the average crack length at the interface, reduced up to ~94% and ~56%, respectively. This study shows that the SPS technique can also apply to joining other UHTCs without any filler, resulting in the new field of developing complex components for the thermal protection system (TPS).     

纳米Ni粉填料对聚硅氮烷连接SiC陶瓷接头性能的影响

研究了活性填料纳米Ni粉对陶瓷先驱体聚硅氮烷连接反应烧结SiC陶瓷接头性能的影响，同时与惰性填料纳米SiC粉及活性填料微米Ni粉进行了对比，指出填料的种类及颗粒度对连接强度均有较大影响。活性填料纳米Ni粉的加入可减少连接层内的孔隙和裂纹，同时还可以与聚硅氮烷的裂解产物及母材发生反应，促进聚硅氮烷的裂解，从而降低连接温度，提高连接强度。当连接温度为1200℃时，其最大抗弯强度达到251．6MPa。微观研究表明，连接层结构较为均匀致密，且与母材间界面结合良好。惰性填料纳米SiC粉对连接强度没有明显改善。微米Ni粉因不能与先驱体形成均匀的连接层而导致连接强度降低。     

Characteristics of deformation joining of aluminum-stainless steel composite sheet

1　INTRODUCTIONAseveryoneknows ,aluminumandstainlesssteelaredifficulttoweldtogether[16 ] .Inthepast,braz ing ,projectionweldingaswellasaluminizingwereused .Nowadays ,anewmethodisputforward ,inwhichthealuminumsheetandstainlesssteelsheetheatedbyinductionheaterareconnectedbypressureofascrew press .Notonlycanthismethodimprovebondingbehaviorofthecompositesheet,butalsocanitraisetheproductivity greatly .Thistechnologyiscalleddeformationjoining ,i.e .pressjoining .InChi na ,ithasbeensuccessfully…     

新时期大学生入党动机偏差及纠偏途径研究

由于大学生自身的特点、社会环境和家庭环境的影响以及学校教育与党建工作的不足,大学生的入党动机呈多元化趋势,表现出复杂性和多样性的特点,直接影响高校思想政治教育工作和学生党建工作的质量。文章就此进行了分析,并针对新形势学生入党动机的多元化,提出相应的纠偏对策。     

Electrical Characterization of a Joined Electroceramic, La0.85Sr0.15MnO3

Pieces of saw-cut La_0.85Sr_0.15MnO₃ were joined at 1150° and 1250°C under a compressive stress. The strains to form the joints were ∼0.1. Joints formed by plastic deformation were examined using scanning electron microscopy, and they were indistinguishable from the bulk. The room-temperature direct-current resistivity of the joined pieces was identical to that measured in the bulk material. This indicated that a sound, electrically conducting joint could be formed using plastic deformation (grain-boundary sliding) with little surface preparation.     

Impedance spectroscopy study and electrical behavior of PMN-PZT actuators joined by ceramic slurry

The solid solution of Pb(Mg,Nb)O₃-Pb(Zr,TiO) O₃ materials have high piezoelectric constant of 600 ∼650 pC/N and electromechanical coupling coefficient k _p of 0.65. Due to such high piezoelectric constant and electromechanical coupling coefficient, Pb(Mg,Nb)O₃-Pb(Zr,TiO)O₃ materials have been attracted attentions for the applications of multilayer ceramic actuators. Actuators can be produced by staking piezoelectric ceramic materials and inner electrodes, alternatively. However, it is difficult to fabricate huge ceramic actuators without any serious problems during the process conditions. Because ceramic are easily cracked during the sintering process, due to strikingly different shrinkage rate between the ceramic materials and metal electrodes. In this research, new jointing methods will be proposed for huge ceramic actuators, and then their electrical properties were investigated. Time dependent leakage current and impedance spectroscopy were employed to expect device performances.