Commercially pure nickel (Ni) was thermomechanically processed to promote an increase in Σ3 special grain boundaries. engineering the character and chemistry of Σ3 grain boundaries in polycrystalline materials can h...
Commercially pure nickel (Ni) was thermomechanically processed to promote an increase in Σ3 special grain boundaries. engineering the character and chemistry of Σ3 grain boundaries in polycrystalline materials can help in improving physical, chemical, and mechanical properties leading to improved performance. Type-specific grain boundaries (special and random) were characterized using electron backscatter diffraction and the segregation behavior of elements such as Si, Al, C, O, P, Cr, Mg, Mn, B, and Fe, at the atomic level, was studied as a function of grain boundary character using atom probe tomography. These results showed that the random grain boundaries were enriched with impurities to include metal oxides, while Σ3 special grain boundaries showed little to no impurities at the grain boundaries. In addition, the influence of annealing time on the concentration of segregants on random grain boundaries was analyzed and showed clear evidence of increased concentration of segregants as annealing time was increased.
This paper presents the results of structural investigations and results of tribological and microhardness tests of the coating obtained by electron beam cladding of a Ni-Cr-Si-Fe-B self-fluxing alloy on low-carbon st...
This paper presents the results of structural investigations and results of tribological and microhardness tests of the coating obtained by electron beam cladding of a Ni-Cr-Si-Fe-B self-fluxing alloy on low-carbon steel. After electron beam treatment high-quality dense layer with a thickness of 1.2-1.8 mm was obtained. The structure of the coating consisted of dendrite crystals based on y-Ni-solid solution and eutectic with complex composition. Microhardness of the coating achieves 370 HV. Wear-resistance of the coating obtained by electron-beam cladding technique was 1.6-fold higher than that of low-carbon carburized steel.
Heat treatments of the HVOF sprayed chromium oxide coating were performed in chamber electric furnace. Effects of heat treatment temperature on dry tribological properties and wear mechanism of the coating were studie...
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Heat treatments of the HVOF sprayed chromium oxide coating were performed in chamber electric furnace. Effects of heat treatment temperature on dry tribological properties and wear mechanism of the coating were studied by microhardness testing machine, scanning electron microcopy (SEM), energy-dispersive spectroscopy (EDS) and friction wear testing machine. Results indicate that comprehensive wear & friction resistance of the coating after heat treatment at 500°C were the best under the experimental condition in this paper. Heat treatment doesn't alter wear mechanism of the coating. The main wear mechanisms of the coating were abrasive wear and slight spalling at 10 N load, but at 25 N load, spalling was the main wear mechanism and abrasive wear also exist.
The article reveals the peculiarities of obtaining Zn anticorrosive diffusion layers on heat-treated metal parts using sherardizing method. It is shown that sherardizing processes can be successfully used as a final h...
The article reveals the peculiarities of obtaining Zn anticorrosive diffusion layers on heat-treated metal parts using sherardizing method. It is shown that sherardizing processes can be successfully used as a final heat treatment operation for some metal parts after hardening in a temperature gap between 350-700 °C. 380-450 °C are the most efficient temperatures of sherardizing process to reveal hardening stresses in details. At the same time, applying sherardizing method for anticorrosive protection of details subjected to final heat treatment may cause a weakening of metal accomplished by a reduction of working properties. This fact can be described by structural changes in metal caused by additional heat impact of sherardizing temperatures.
Based on Molecular Dynamics and quantum mechanics, proton transfer reaction in the poly (2, 5-polybenzimidazole) (ABPBI) used as the high temperature proton exchange membrane is simulated by the molecule simulation me...
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Tribology is an important method for evaluating the coefficient of friction and wear of friction pairs of technical materials. The most commonly used modes are "pin on disc", resp. "ball on disc". ...
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A 3D numerical model is developed for estimating breaking wave impact forces on an inclined cylindrical pile. Because the inclined pile installed in the numerical model, unlike the experiment, is modeled as a rigid ob...
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In a mixed environment of autonomous driverless vehicles and human driven vehicles operating on the same road, identifying intentions of human drivers and interacting with them in a compliant and responsible manner be...
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In a mixed environment of autonomous driverless vehicles and human driven vehicles operating on the same road, identifying intentions of human drivers and interacting with them in a compliant and responsible manner becomes a challenging problem for the driverless vehicles. In this paper, the problem of vehicle interaction at an intersection merging scenario is formulated as an Intention-Aware motion planning problem using the tools from Mixed Observability Markov Decision Process (MOMDP). We utilize the tools from recent intention aware planning framework to demonstrate a merging behavior in the presence of human drivers by trying to infer and act according to the intentions of the human drivers. A driver behavior model for T-junction intersections is developed in order to calculate the probabilistic state transition functions of the MOMDP model. With proposed solution, it is demonstrated that using intention aware planning improves performance in comparison to present time to merge approach by lowering accident probability and intersection navigation duration. The proposed method is tested on a real autonomous vehicle (AV) in the presence of human driven vehicles to validate our approach.
The intrinsic spin Hall effect originates from the topology of the Bloch bands in momentum space. The duality between real space and momentum space calls for a spin Hall effect induced from a real space topology in an...
The intrinsic spin Hall effect originates from the topology of the Bloch bands in momentum space. The duality between real space and momentum space calls for a spin Hall effect induced from a real space topology in analogy to the topological Hall effect of skyrmions. We theoretically demonstrate the topological spin Hall effect in which a pure transverse spin current is generated from a skyrmion spin texture.
In this paper, Microencapsulated paraffin/polyurea (PU) phase change materials were prepared through an interfacial polymerization method using composite paraffin with solid/liquid mass ratio 3:7 as core materials, 2,...
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