Interface regulation effects on mechanical behavior of heterostructure Ti6Al4V/TiAl-based laminated composite sheets

Design of architectured composites with layered-ordered structure can solve the strength-toughness mismatch problem of structural materials. In the present study, heterostructure Ti6Al4V/TiAl laminated composite sheets with different thicknesses of interface layer and TiAl composite layer were successfully produced by hot-pressing technology. The effects of interface regulation and laminated structure on their mechanical properties, crack propagation, and fracture behavior were studied. The results indicated that compressive strength of the sheets increased with the decrease in interface thickness. Compressive strength of TiAl composite sheet with thicker composite layer reached 1481.55 MPa at the arrester orientation with sintering holding time of 40 min, which was 25.96% higher than that of the sheet obtained at 120 min. Analysis indicated that the interface area transferred stress through slip bands and through-interface cracks. Compressive strength at the divider orientation reached 1443.06 MPa, which was 45.78% higher than that of the sheet obtained at 120 min. In this case, the interface area transferred stress through slip bands and along-interface cracks. For TiAl composite sheets with thinner composite layer, compressive strength was further improved to 1631.01 MPa and 1594.66 MPa at the arrester and divider orientations with sintering holding time of 40 min, respectively. The ductile metal layer exerted a significant toughening effect. Both interface regulation and laminated structure transformation could enhance the hetero-deformation induced (HDI) strengthening and improve the comprehensive mechanical properties of the composite sheets.     

Achieving Rich and Active Alkaline Hydrogen Evolution Heterostructures via Interface Engineering on 2D 1T‐MoS2 Quantum Sheets

Large‐scale production of hydrogen from water‐alkali electrolyzers is impeded by the sluggish kinetics of hydrogen evolution reaction (HER) electrocatalysts. The hybridization of an acid‐active HER catalyst with a cocatalyst at the nanoscale helps boost HER kinetics in alkaline media. Here, it is demonstrated that 1T–MoS₂ nanosheet edges (instead of basal planes) decorated by metal hydroxides form highly active ${\text{edge}}_{{\text{1T‐MoS}}_{\text{2}}}$/ ${\text{edge}}_{\text{Ni}{(\text{OH})}_{\text{2}}}$ heterostructures, which significantly enhance HER performance in alkaline media. Featured with rich ${\text{edge}}_{{\text{1T‐MoS}}_{\text{2}}}$/ ${\text{edge}}_{\text{Ni}{(\text{OH})}_{\text{2}}}$ sites, the fabricated 1T–MoS₂ QS/Ni(OH)₂ hybrid (quantum sized 1T–MoS₂ sheets decorated with Ni(OH)₂ via interface engineering) only requires overpotentials of 57 and 112 mV to drive HER current densities of 10 and 100 mA cm^?2, respectively, and has a low Tafel slope of 30 mV dec^?1 in 1 m KOH. So far, this is the best performance for MoS₂‐based electrocatalysts and the 1T–MoS₂ QS/Ni(OH)₂ hybrid is among the best‐performing non‐Pt alkaline HER electrocatalysts known. The HER process is durable for 100 h at current densities up to 500 mA cm^?2. This work not only provides an active, cost‐effective, and robust alkaline HER electrocatalyst, but also demonstrates a design strategy for preparing high‐performance catalysts based on edge‐rich 2D quantum sheets for other catalytic reactions.     

NSA-500-1型氩弧焊机VD9不同接法对引弧和稳弧的影响

从一起NSA－500－1型氩弧焊机故障，分析其高压脉冲旁路二极管VD9不同接法对引弧、稳弧及设备安全的影响。     

φ1m氨合成塔20钢异径管失效分析

分析了氨合成塔底部副线20钢异径管爆破的原因。结果表明：异径管长期处于200℃以上工作，管内H2与管材中的碳或Fe3发生化学反应，生成CH4致使管内脱碳并产生裂纹，异径管强度降低脆性增加，导致爆破。     

DXDK800自动充填包装机料袋长度的调整

本文主要介绍了在DXDK800自动充填包装机中 ,采用一种新型的齿轮—蜗轮、蜗杆差速器来对膜片的进给速度进行微量的调整。及采用一种新型的可调式偏心链轮来调整横封辊的瞬时线速度 ,使其与料袋膜的进给速度相一致     

TiAl基合金板材制备技术的发展现状

综述了TiAl基合金板材制备技术的发展现状。介绍了的制备TiAl基合金板材三种技术的工艺过程及制得的TiAl基合金板材的显微组织和力学性能。     

The need for style systems in ODA

Many advanced document systems provide a formatting mechanism called ‘style sheets’ Style sheets provide a great deal of flexibility in describing a document's format, and allow easy maintenance of different house styles for a collection of documents. In this paper, we describe the basics of general style sheet systems, argue that successful document interchange must include the exchange of style sheet information, and evaluate ODA's style mechanism against this requirement.     

上海市用电负荷管理系统主站异地冗灾备份方案研究

对上海市用电负荷管理系统主站灾备系统的建设进行可行性研究,根据系统现有结构,结合主流技术提出建议性的方案.重点对各种设备技术进行分析,包括涉及计算机、网络、软件等各方面的设备技术,提出建设原则及实施建议.     

发电机用DJL350磁极钢板的开发与应用

本文论述了高强度冷轧磁极板的试制性研究，应用性研究及在开生桥机组上的实施。通过与国外材料的对比，研究了材料的化学成分、力学性能、磁性能、金相组织及其与性能的关系。并对其实际应用效果进行了分析总结。     

工艺条件对薄片陶瓷材料凝胶流延成型的影响

利用有机单体的聚合原理，成功进行了陶瓷薄片材料的凝胶流延成型。讨论了工艺条件对成型的影响。使用惰性气氛保护克服了单体聚合反应中的氧气阻聚问题，浆料在一定温度和气氛条件下能够顺利完成聚合反应。所成型的坯体具有良好的强度和柔韧性，在1550℃经2h烧结，烧结样品显微结构均匀，没有发现晶粒异常长大现象，烧结体致密度达到97．7％。