Ferritic stainless steels are promising candidates for IT-SOFC interconnect applications due to their low cost and resistance to oxidation at SOFC operating temperatures. However, steel candidates face several challenges, including long term oxidation under interconnect exposure conditions, which can lead to increased electrical resistance, surface instability, and poisoning of cathodes due to volatilization of Cr. To potentially extend interconnect lifetime and improve performance, a variety of surface treatments were performed on AISI 441 ferritic stainless steel coupons prior to application of a protective spinel coating. The coated coupons were then subjected to oxidation testing at 800 and 850 degrees C in air, and electrical testing at 800 deg C in air. While all of the surface-treatments resulted in improved surface stability (i.e., increased spallation resistance) compared to untreated AISI 441, the greatest degree of improvement (through 20,000 hours of testing at 800 deg C and 14,000 hours of testing at 850 deg C) was achieved by surface blasting.

关键词：合金；尖晶石；不锈钢；表面处理；涂料

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The research under this project focused on a theoretical and computational modeling of dislocation dynamics of mesoscale deformation of metal single crystals. Specifically, the work aimed to implement a continuum statistical theory of dislocations to understand strain hardening and cell structure formation under monotonic loading. These aspects of crystal deformation are manifestations of the evolution of the underlying dislocation system under mechanical loading. The project had three research tasks: 1) Investigating the statistical characteristics of dislocation systems in deformed crystals. 2) Formulating kinetic equations of dislocations and coupling these kinetics equations and crystal mechanics. 3) Computational solution of coupled crystal mechanics and dislocation kinetics.

关键词：金属；统计力学；耦合；晶体；变形

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Two kinds of welding methods,including SMAW and GTAW,were employed to connect 16MnR steel and 2205 steel.OM and TEM was used to observe the microstructure.EDX line scan was used to analyze elements in special areas of the joint.The results show that the degree of carbon migration in the side of 16MnRofthe seam welded by GTAW is larger than that by SMAW.Particle and chain-island are two maiin form of Fe3C in micro-area of carbon migration.The grain size of seam material in GTAW section is larger than that of SMAW and the content of austenitic of seam material in GTAW section is more than that of SMAW.The tongues in the side of 16MnR appear in both two seams welded by SMAW and GTAW and they are parts from base metal.

关键词：异种钢；焊接方法；热输入；微观结构

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Gas carburizing is a widely used heat treatment process in which carbon is transferred into steel. The hardening reliability involves an active control of mass transfer during the process and this is why understanding diffusion in solids is so essential to model the process. The currently used models are often based on the simplest, one-dimensional form of the diffusion equation in which diffusivity depends on composition. The objective of this work is to develop a model of carbon diffusion in multicomponent alloy subjected to pulse carburizing. The model is based on the Darken method (bi-velocity method) in which the diffusion velocity depends on the diffusion potential gradient and is independent of the choice of the reference frame while the drift velocity is common for the carbon and steel components. Our model allows predicting the kinetics of carbon transfer at various treatment conditions and is applied to the pulse carburizing process at constant temperature. The process is carried out by repeating consecutively a carburization stage, when the carburizing gas is supplied into a carburizing chamber, and a diffusion stage at vacuum conditions, when the carburizing gas is exhausted and only the diffusion of carbon takes place. The numerical calculations are made for varying carburization and diffusion periods and are confirmed by the experimental results. On the basis of the series of computer experiments some findings that are important in designing the carburizing technology are formulated.

关键词：脉冲渗碳；扩散；双速度法

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Based on node test and finite element analysis results of four different structural form enhanced nodes,failure modes,hysteretic behavior,bearing capacity,ductility and energy dissipation capacity of nodes are analyzed comprehensively and comparatively for more in-depth exploration about the seismic performance of symmetric enhanced nodes.The results showed that all the symmetric enhanced nodes have full hysteretic curve and energy dissipation capacity.On the whole,The flange-plate reinforced node exhibit better seismic performance.

关键词：钢框架；加强节点；循环加载试验；有限元分析

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Although steel orthotropic deck is currently the most widely adopted solution for long-span bridges, the poor adhesion to the upper asphalt layers still represents a serious problem without a clear solution. In recent decades many techniques that involve the use of special bituminous bonding coats, reinforced asphalt membranes, net-reinforced steel deck surfaces, or epoxy asphalt binders have been applied, with varying results, to improve the level of adhesion of the asphalt pavement to the steel surface. In this experimental study, two such techniques were adopted to investigate the shear resistance of steel-asphalt pavement systems. The first technique used epoxy asphalt both as a bonding coat and as a binder of the upper asphalt layer, while the second technique involved the use of a reinforced asphalt membrane that was applied on the steel deck before overlaying with conventional hot-mix asphalt (HMA). The Ancona Shear Testing Research and Analysis shear test device was used to evaluate the shear resistance of different types of HMA-steel interfaces and to investigate the effects of temperature and normal stress. The results have been compared with the shear properties of bitumen-coated interfaces, studied in previous research. The results showed that epoxy asphalt guaranteed high performance regardless of the test temperature. However, the shear resistance of the system with the asphalt membrane was lower than with the epoxy asphalt, although it was higher than the resistance of bitumen-coated interfaces at high temperatures.

关键词：正交异性钢桥；钢铁；沥青膜

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Improved software interoperability is key to realizing more fully the potential benefits of integrated and accelerated project delivery in a way that also somehow ensures product quality. The increasing appeal of three-dimensional (3-D) building information modeling (BIM) notions applied to bridges [known as bridge information modeling (BrIM)] motivates the need for principled prescriptions of associated electronic data exchanges between various project stakeholders and the various software applications that they use. Such data exchanges must be sufficiently precise to facilitate detailing for fabrication and construction while being sufficiently concise to facilitate parametric modeling and thereby avoid needless data duplication. The highway geometry to which bridges must conform distinguishes BrIM from the building column grid orientation of BIM at the outset of the bridge life cycle. In contrast to the overdefined highway geometry in the LandXML data exchange standard, a 3-D control curve is defined, presented, illustrated, and recommended as the basis for parametric data exchange suitable through the life cycle of steel Ⅰ-girder bridges on (straight and) curved alignments. This 3-D control curve combines in a single curve the traditional horizontal control line and profile grade line that bridge structural engineers receive from highway designers to define bridge geometry. Data exchanges associated with three distinct stages in the life cycle of a steel bridge are defined and illustrated: analysis and design, detailing for fabrication, and erection and construction. The data exchange based on a 3-D control curve provides the data integrity required through the life cycle of a steel bridge.

关键词：三维参数；钢铁；曲线钢桥

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We consider a cutting problem, which have a practical application. In this problem, items are being cut from larger items, for example textile patterns from a panel of cloth. We deal steel tubes of given length, which have to be sawed from longer steel tubes. These longer steel tubes come with given costs and the sawing has to be planned such that the total costs are minimized.

关键词：切割的问题；一维；吉尔摩和戈莫里方法；钢铁

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To develop an effective software for finite element (FE) model updating of bridges, the interface technology between VC++ and MATLAB was investigated firstly, and then a software for updating FE model of bridges, named 'Doctor for Bridges' (version 1.0) was developed. Finally, a model ofconcrete-filled steel tube arch bridge was applied to verify the performance and effectiveness of the proposed software.

关键词：桥梁；有限元模型修正；接口技术

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High hard armor steels are used on many tactical vehicles, such as the Stryker and the mine-resistant, ambush-protected vehicle. Although they provide good protection against armor-piercing threats, these steels corrode rapidly without the use of a good corrosion protective coating. Corrosion on military ground vehicles increases the infrared signal from the vehicle that the topcoat camouflage usually inhibits, making the vehicle more vulnerable to detection by the enemy. Stryker vehicles are prohibited from using hex-chrome and are currently coated without any pretreatment or conversion coating. The products demonstrated here will satisfy the hexavalent chrome prohibition while minimizing environmental impact and worker safety. This demonstration plan is designed to generate the data necessary for authorization and implementation decisions by appropriate authorities within the U.S. Department of Defense.

关键词：护甲；腐蚀；六价铬；高硬度装甲腐蚀

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