Finite Element Analysis of Residual Stress in the Diffusion Zone of Mg/Al Alloys

In this study, the finite element method was applied for analyzing the effect of annealing temperatures on residual stress in the diffusion zone of AZ31 Mg and 6061 Al alloys. The microstructure and mechanical behavior of the diffusion zone were also investigated. Simulations on the annealing of the welded specimens at 200°C, 250°C, and 300°C were conducted. Moreover, experiments such as diffusion bonding and annealing, analysis of residual stress by X-ray diffraction, elemental analysis using an electron probe microanalyzer, and microstructure investigation via scanning electron microscopy were performed for further investigation of the diffusion layers. According to the results of the simulations and experiments, the diffusion layers widen with increasing annealing temperatures, and the results of the simulations are in good agreement with those of the experiments. The microstructure and elemental distribution were the most uniform and the residual stress was the least for samples annealed at 250°C. Thus, 250°C was found to be the most appropriate annealing temperature

Conversion of multi-layered Mg-based carrier to hydrogen storage performance

The mixed powder method and covering method were adopted to prepare a composite that has hydrogen storage properties. In the experimental process, the alloy phases Mg2Ni and NiTi generated regularly; the penetration of the hydrogen atoms to the material was considered as the adsorption of the material to the hydrogen atoms; the original thermodynamic equation was edited; the crystal phases were optimized by adjusting the parameters about the material composition and gas concentration, so that providing advantageous channels of the hydrogen atoms in and out to improve the hydrogen storage properties. The results showed that integer multiples adjustment to trace element Ti could make hydrogen storage properties maximizing optimize and have controllability for the capacity and rate of hydrogen storage according to the newly editing equation. The innovation was to edit out equation that can improve the hydrogen storage properties through adjusting three parameters of trace element Ti, adsorption and penetration to find the most optimal condition improving the hydrogen storage properties

Study on AgCl/Al2O3 Catalyst Coating on Metal Workpiece Surface by Electrophoretic Deposition and Its Overall Catalytic Performance

This paper is a study of the coating technique of AgCl/Al2O3 catalyst on metal-based surfaces. In order to remove nitrogen oxides from the exhaust of marine diesel engines, this paper proposes a method of electrophoretic deposition and designs an electrophoretic deposition apparatus according to the coating conditions. An in-house developed catalyst was coated on a specific stainless-steel workpiece by the electrophoretic deposition method under the conditions of appropriate voltage and catalyst solution concentration. The surface and cross section of AgCl/Al2O3 coating on stainless steel were observed by scanning electron microscope, and the thickness of catalyst coating after coating was determined. In this study, an exhaust gas evaluation system was built, and a removal test of nitrogen oxides from diesel exhaust gas was conducted under the environment of temperature cyclic change, and repeated experiments proved that the coated workpiece could still effectively remove harmful nitrogen oxides from the exhaust gas. Converting them to N2 provides a new idea for ship exhaust gas purification

Simulations about the effect of heat treatment temperatures on the properties of diffusion bonded Mg/Al joints

In this study, Finite elements method (FEM) was used for simulations on the annealing treatment. And the distributions of residual stress were obtained from the resualts of simulitions. Besides, in order to study the mechanical properties. Composite plates of AZ31B magnesium alloys and 6061 aluminum alloys were fabricated by vacuum diffusion bonding method. Then experiments about annealing, measurement of residual stresses and tension test were also carried out. The results of residual stresses obtained by X-ray diffraction (XRD) were compared with the results of simulations. It can be thought that the results of residual stress obtained from simulations and that from experiments are in a good agreement. What’s more, The residual stress after annealing at 250°C is the least of all, while the tensile strength is the strongest. On the basis of results of simulations and experiments, the conclusion can be obtained that 250°C is the most appropriate annealing temperature

Simulations about the effect of heat treatment temperatures on the properties of diffusion bonded Mg/Al joints

In this study, Finite elements method (FEM) was used for simulations on the annealing treatment. And the distributions of residual stress were obtained from the resualts of simulitions. Besides, in order to study the mechanical properties. Composite plates of AZ31B magnesium alloys and 6061 aluminum alloys were fabricated by vacuum diffusion bonding method. Then experiments about annealing, measurement of residual stresses and tension test were also carried out. The results of residual stresses obtained by X-ray diffraction (XRD) were compared with the results of simulations. It can be thought that the results of residual stress obtained from simulations and that from experiments are in a good agreement. What’s more, The residual stress after annealing at 250°C is the least of all, while the tensile strength is the strongest. On the basis of results of simulations and experiments, the conclusion can be obtained that 250°C is the most appropriate annealing temperature

A Human-Computer Control System Based on Intelligent Recognition of Eye Movements and Its Application in Wheelchair Driving

This paper presents a practical human-computer interaction system for wheelchair motion through eye tracking and eye blink detection. In this system, the pupil in the eye image has been extracted after binarization, and the center of the pupil was localized to capture the trajectory of eye movement and determine the direction of eye gaze. Meanwhile, convolutional neural networks for feature extraction and classification of open-eye and closed-eye images have been built, and machine learning was performed by extracting features from multiple individual images of open-eye and closed-eye states for input to the system. As an application of this human-computer interaction control system, experimental validation was carried out on a modified wheelchair and the proposed method proved to be effective and reliable based on the experimental results

Simulation of Flow Stress Characteristic During Two-stage Hot Deformation Process in AZ31B Magnesium Alloy

A 2-D CA model has been developed to simulate two-stage hot deformation processing of magnesium (Mg) alloy. Based on the fact that Mg has an HCP crystal structure with six-fold symmetry, the model employs hexagonal CA lattice. The physically-based model has integrated the effects of individual metallurgical phenomena related with the hot deformation, including dynamic recrystallization (DRX), static recovery, static recrystallization (SRX), meta-dynamic recrystallization (MDRX) and grain growth, etc. The model is validated by simulating single-stage and two-stage hot compression tests of AZ31B. The effects of temperature, strain rate, the interval and pre-strain on stress-strain curves are investigated. The calculated results are compared with the available experimental findings in AZ31B Mg alloy, and the simulated results agree well with the experimental results and theoretical models