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Beyond Graphene Anode materials for Emerging Metal Ion Batteries and Supercapacitors

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Nano-Micro Letters 2018年第4期10卷 228-254页

作者： Santanu Mukherjee Zhongkan Ren Gurpreet Singh department of mechanical and nuclear Engineering Kansas State University

Intensive research effort is currently focused on the development of efficient, reliable, and environmentally safe electrochemical energy storage systems due to the ever-increasing global energy storage demand. Li ion battery systems have been used as the primary energy storage device over the last three decades. However, low abundance and uneven distribution of lithium and cobalt in the earth crust and the associated cost of these materials, have resulted in a concerted effort to develop beyond lithium electrochemical storage systems. In the case of non-Li ion rechargeable systems, the development of electrode materials is a significant challenge, considering the larger ionic size of the metal-ions and slower kinetics. Two-dimensional(2D) materials, such as graphene, transition metal dichalcogenides, MXenes and phosphorene, have garnered significant attention recently due to their multi-faceted advantageous properties: large surface areas, high electrical and thermal conductivity, mechanical strength, etc. Consequently, the study of 2D materials as negative electrodes is of notable importance as emerging non-Li battery systems continue to generate increasing attention. Among these interesting materials, graphene has already been extensively studied and reviewed, hence this report focuses on 2D materials beyond graphene for emerging non-Li systems. We provide a comparative analysis of 2D material chemistry, structure, and performance parameters as anode materials in rechargeable batteries and supercapacitors.

关键词： Two-dimensional materials Transition metal dichalcogenides MXene Exfoliation Top-down Anodes

Effect of thermomechanical treatment on microstructure and hardness behavior of AZ63 magnesium alloy

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Acta Metallurgica Sinica(English Letters) 2009年第6期22卷 401-407页

作者： H. Jafari M.H. Idris A. Ourdjini G. Payganeh department of materials Engineering Faculty of Mechanical EngineeringUniversiti Teknologi Malaysia department of materials Engineering Faculty of Mechanical EngineeringShahid Rajaee Teacher Training University department of materials Engineering Faculty of Mechanical Engineering Shahid Rajaee Teacher Training University

Due to their high specific strength and low density, magnesium alloys are widely used in many weight-saving applications. This research is aimed at investigating the microstructure and hardness of commercial AZ63 alloy specimens subjected to two different thermomechanical treatments （TMTs）. For the first TMT, after solution treated at the temperature of 380 ℃ for 20 h, AZ63 alloy specimens were 5% cold worked by rolling process followed by ageing at the temperatures of 150 ℃and 250 ℃ for 3, 9 and 25 h. In the second TMT, the specimens were solution treated at the temperature of 380 ℃ for 20 h, underwent 2% cold worked and quenched in water of 0 ℃. Half of the specimens were then 2% cold worked whilst the rest were rolled to 8% cold worked. All the specimens were then aged at the temperatures of 150 ℃ and 250 ℃ for 3, 9 and 25 h. Optical microscope was used to analyze the microstructures of the specimens. Hardness test was too conducted to measure the effect of the treatments on the specimens. Results show that two-step aging enhances the hardness of the specimens due to the distribution of fine β-phase （MglTA112） in the alloy matrix. The results also reveal that, the best hardness from the first TMT was produced by specimen that was pre-aged at 150 ℃ whereas, in the second TMT, aging at 250 ℃ exhibited the best hardness values.

关键词： Thermomechanical treatment Magnesium alloys Cold work Aging AZ63

Multi-scale study of ductility-dip cracking in nickel-based alloy dissimilar metal weld

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Journal of materials Science & Technology 2019年第4期35卷 545-559页

作者： Yifeng Li Jianqiu Wang En-Hou Han Wenbo Wu Hannu Hanninen Key Laboratory of nuclear materials and Safety Assessment Institute of Metal ResearchChinese Academy of Sciences School of materials Science and Engineering University of Science and Technology of China department of mechanical Engineering Aalto University

A ductility-dip-cracking(DDC)-concentrated zone(DCZ) in a width of about 3 mm was observed adjacent to the AISI 316 L/52 Mw fusion boundary(FB) in 52 Mw. The morphology, microstructure, mechanical and thermal properties and corrosion behavior in simulated primary water of DDC/DCZ were investigated by scanning electron microscopy(SEM), transmission electron microscopy(TEM), 3 D X-ray tomography(XRT), 3 D atom probe(3 DAP), slow strain rate tensile(SSRT) testing and thermal dilatometry. The results indicate that DDCs are random-shaped and disc-like cavities with corrugated structure of inner surface and are parallel in groups along straight high-angle boundaries of columnar grains, ranging from micrometers to millimeters in size. Large-size M_(23)C_6 carbides dominate on the grain boundaries rather than MC(M=Nb, Ti), and thus the bonding effect of carbides is absent for the straight grain *** impurity segregation of O is confirmed for the inner surfaces of DDC. The oxide film formed on the inner surface of DDC(about 50 nm) is approximately twice as thick as that on the matrix(about 25 nm)in simulated primary water. The yield strength, tensile strength and elongation to fracture of 52 MwDCZ(400 MPa, 450 MPa and 20 %, respectively) are lower than those of 52 Mw-MZ(460 MPa, 550 MPa and 28 %, respectively). The intrinsic high-restraint weld structure, the additional stress/strain caused by the thermal expansion difference between AISI 316 L and 52 Mw as well as the detrimental carbide precipitation and the resulting grain boundary structure all add up to cause the occurrence of DCZ in the dissimilar metal weld.

关键词： Dissimilar metal weld Nickel-base alloy Ductility-dip cracking(DDC) Slow strain rate tensile(SSRT) testing Thermal expansion coefficient

mechanical Properties of Al/BN Nanocomposites Fabricated by Planetary Ball Milling and Conventional Hot Extrusion

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Acta Metallurgica Sinica(English Letters) 2018年第3期31卷 245-253页

作者： Reza Gostariani Ramin Ebrahimi Mohsen Asadi Asadabad Mohammad Hossein Paydar department of materials Science and Engineering School of Engineering Shiraz University materials and nuclear Fuel Research School Nuclear Science and Technology Research InstituteTehran Iran

In this study,Al matrix nanocomposites containing 1,2 and 4 wt% nano-boron nitride were fabricated by mechanical milling and hot *** mechanical properties of all extruded samples were ***,the morphology and microstructure of the milled composite powders were characterized using two types of electron *** results showed that a high fraction of the boron nitride nanoparticles dissolved and formed a solid solution in Al matrix during the milling *** the process of solid solution formation,the work hardening rate of the composite powders *** led to a morphological change in the composite powders and resulted in equiaxed *** powder particle size also decreased after the milling *** increasing boron nitride content within a range of 0--4 wt% in the hot extruded samples,tensile stress increased from 212 to 333 *** hardness of the nanocomposite samples including 1,2 and 4 wt% boron nitride improved approximately 55,70 and 90% in comparison with pure Al,respectively.

关键词： Al/BN nanocomposite Planetary ball milling Hot extrusion mechanical properties Microstructure

In situ study of the mechanical properties of airborne haze particles

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Science China(Technological Sciences) 2015年第12期58卷 2046-2051页

作者： DING MingShuai HAN WeiZhong LI Ju MA Evan SHAN ZhiWei Center for Advancing materials Performance from the Nanoscale (CAMP-Nano) and Hysitron Applied Research Center in China (HARCC) State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong University department of nuclear Science and Engineering and department of materials Science and Engineering Massachusetts Institute of Technology department of materials Science and Engineering Johns Hopkins University

Particulate pollution has raised serious concerns regarding its potential impacts on human health in developing countries. However, much less attention has been paid to the threat of haze particles to machinery and industry. By employing a state-of-the-art in situ scanning electron microscope compression testing technique, we demonstrate that iron-rich and fly ash haze particles, which account for nearly 70% of the total micron-sized spherical haze particles, are strong enough to generate abrasive damage to most engineering alloys, and therefore can generate significant scratch damage to moving contacting surfaces in high precision machineries. Our finding calls for preventive measures to protect against haze related threat.

关键词： haze particle hardness abrasive damage precision industry

Improved corrosion resistance of Mg alloy AZ31B induced by selective evaporation of Mg using large pulsed electron beam irradiation

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Journal of materials Science & Technology 2019年第5期35卷 891-901页

作者： Woo Jin Lee Jisoo Kim Hyung Wook Park department of mechanical Aerospace and Nuclear Engineering Ulsan National Institute of Science and Technology

Large pulsed electron beam(LPEB) irradiation was employed as a surface treatment of magnesium(Mg)alloy AZ31B to enhance its corrosion and wear resistance. Selective evaporation of Mg induced by LPEB irradiation at an energy density of 5J/cm^2 for 40 cycles has led to the formation of an Al-enriched resolidified layer with nano-grained structure consisting of Mg3.1 Al0.9 metastable phase. The formation of such a re-solidified layer after LPEB irradiation has enabled a decrease in corrosion rate of Mg alloy AZ31B in 3.5% NaCl solution. Different equivalent electrical circuit models were proposed to account for the corrosion behavior of untreated Mg alloy AZ31B and those subjected to LPEB irradiation. A decrease in wear depth when compared to that of the untreated alloy suggests an increase in wear resistance of LPEB-irradiated Mg alloy AZ31B. Adhesive wear is the predominant mechanism of untreated Mg alloy AZ31B while abrasive wear mechanism dominates for LPEB-irradiated Mg alloy AZ31B.

关键词： Magnesium alloys Electron beam treatment Corrosion resistance Microstructure Rapid re-solidification Wear resistance

Separating viscoelasticity and poroelasticity of gels with diferent length and time scales

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Acta Mechanica Sinica 2014年第1期30卷 20-27页

作者： Qi-Ming Wang Anirudh C.Mohan Michelle L.Oyen Xuan-He Zhao Soft Active materials Laboratory Department of Mechanical Engineering and Materials ScienceDuke University Cambridge University Engineering department

Viscoelasticity and poroelasticity commonly coexist as time-dependent behaviors in polymer gels. Engineering applications often require knowledge of both behaviors separated; however, few methods exist to decouple viscoelastic and poroelastic properties of gels. We propose a method capable of separating viscoelasticity and poroelasticity of gels in various mechanical tests. The viscoelastic char- acteristic time and the poroelastic diffusivity of a gel define an intrinsic material length scale of the gel. The experimen- tal setup gives a sample length scale, over which the solvent migrates in the gel. By setting the sample length to be much larger or smaller than the material length, the viscoelasticity and poroelasticity of the gel will dominate at different time scales in a test. Therefore, the viscoelastic and poroelastic properties of the gel can be probed separately at different time scales of the test. We further validate the method by finite-element models and stress-relaxation experiments.

关键词： Poroviscoelasticity Hydrogel. Tissue. Stressrelaxation test Indentation

Low temperature annealing of metals with electrical wind force effects

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Journal of materials Science & Technology 2019年第4期35卷 465-472页

作者： Daudi Waryoba Zahabul Islam Baoming Wang Aman Haque Engineering Applied MaterialsPenn State UniversityCollege Place mechanical & nuclear Engineering Penn State UniversityUniversity Park

Conventional annealing is a slow, high temperature process that involves heating atoms uniformly, i.e., in both defective and crystalline regions. This study explores an electrical alternative for energy efficiency,where moderate current density is used to generate electron wind force that produces the same outcome as the thermal annealing process. We demonstrate this on a zirconium alloy using in-situ electron back scattered diffraction(EBSD) inside a scanning electron microscope(SEM) and juxtaposing the results with that from thermal annealing. Contrary to common belief that resistive heating is the dominant factor, we show that 5 × 10~4 A/cm^2 current density can anneal the material in less than 15 min at only135?C. The resulting microstructure is essentially the same as that obtained with 600?C processing for360 min. We propose that unlike temperature, the electron wind force specifically targets the defective regions, which leads to unprecedented time and energy efficiency. This hypothesis was investigated with molecular dynamics simulation that implements mechanical equivalent of electron wind force to provide the atomistic insights on defect annihilation and grain growth.

关键词： Annealing Grain-growt Electron backscattered diffraction(EBSD) Molecular dynamics simulations Electron wind force

Analysis and Modeling of Friction Stir Processing-Based Crack Repairing in 2024 Aluminum Alloy

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Acta Metallurgica Sinica(English Letters) 2017年第3期30卷 228-237页

作者： Jun-Gang Ren Lei Wang Dao-Kui Xu Li-Yang Xie Zhan-Chang Zhang department of mechanical Engineering and Automation Northeastern University department of Electromechanical Engineering Shenyang Aerospace University Key Laboratory of nuclear materials and Safety Assessment Institute of Metal ResearchChinese Academy of Sciences

Abstract A friction stir processing-based method was used to repair cracks in the 2024 aluminum alloy plates. The temperature field and plastic material flow pattern were analyzed on the basis of experimental and finite element simulation results. Microstructure and tensile properties of the repaired specimens were studied. The results showed that the entire crack repairing was a solid-phase process and plastic materials tended to flow toward the shoulder center and then resulted in the repairing of cracks. Meanwhile, the coarse grain structures were refined in repaired zone （RZ）, while the grains in thermal-mechanically affected zone and heat-affected zone were elongated and driven to grow up. Meanwhile, large phases are crushed into small particles and dispersed inside the RZ. Finally, the strength of the repaired specimens can be restored dramatically and their ductility can be partially restored. After heat treatment, the tensile properties of the repaired specimens can be further enhanced.

关键词： Friction stir processing Crack repairing Aluminum alloy Microstructure Hardness Tensile properties