Wei Lv

Bio: Wei Lv is an academic researcher from Shenyang Aerospace University. The author has contributed to research in topics: Austenite & Machinability. The author has an hindex of 4, co-authored 22 publications receiving 38 citations. Previous affiliations of Wei Lv include Shenyang University of Technology.

Advances on FeCuNbSiB Nanocrystalline Soft Magnetic Powder Cores

Abstract: For the past few years, nanocrystalline soft magnetic alloy has become hot topic in the field of strategic functional materials based on its excellent magnetic properties and advantages of energy saving, low cost, etc. With rapid innovationof various new type soft magnetic materials, FeCuNbSiB soft magnetic powder cores havebeen gradually turning into researching focusin soft magnetic material field for its excellent high frequency properties, such as high magnetic permeability (μ) and quality factor (Q), low core loss (Pc) and coercivity (Hc), etc.This paper mainly reviews the recent advances and technological achievements of FeCuNbSiB nanocrystalline soft magnetic powder cores, and also provides a brief introduction of FeCuNbSiB/Mn-Zn ferrite powder core, one new type composite magnetic powder core. Finally, future developing trend for FeCuNbSiB nanocrystalline powder cores isalso prospectedcompendiouslyin the paper.

Research on Annealing Process for Amorphous & Nanocrystalline Soft Magnetic Alloy with High μi and Low Pc

Abstract: Recent advance and application about Fe-based amorphous nanocrystalline alloy have been reviewed, the latest achievement of static stress annealing, continuous moving stress annealing, and magnetic field annealing for the alloy discussed, and future tendency of Fe-based amorphous nanocrystalline prospected in the paper.

Investigations on Low Environmental Impact Machining Processes of Free Cutting Austenitic Stainless Steels

Abstract: In the present paper, sulfur, RE (rare earth) and bismuth were added to an austenite stainless steel. Low environmental impact machining processes of free cutting austenitic stainless steels was investigated by machinability testing. The results show that a significant amount of grey and dispersed inclusions were found in steel B. The inclusions are typical sulfide inclusions, and bismuth element is attached to double end of manganese sulfide inclusions. Some inclusions exhibit globular shape due to the presence of rare earths elements in steel B. Chip morphology was improved in steel B under the same turning conditions. The machinability of steel B is much better than that of steel A. This is attributed to the presence of free-cutting additives of sulfur, RE and bismuth in the austenitic stainless steels. Satisfactory mechanical properties were also obtained under the conditions of our experiments. The reasons why satisfactory mechanical properties were obtained may lie in that the sulfides and bismuth are soft phase, and the presence of rare earths elements contributes to the improvement of the toughness of the austenitic stainless steels.

Study of Microstructure and Mechanical Properties of Hot-Rolled Ultra-High Strength Ferrite-Bainite Dual Phase Steel

Abstract: Effects of thermo-mechanical control processing (TMCP) on microstructure and mechanical properties of hot-rolled ultra-high strength ferrite-bainite dual phase steel were investigated on a laboratory hot rolling mill. The results have shown that the microstructure containing ferrite and bainite can be obtained by TMCP. Ultimate tensile strength of all the specimens exceeded 1000MPa. Finish rolling temperatures affect the mechanical properties of ultra-high strength ferrite-bainite dual phase steel. Ultimate tensile strength reached 1078MPa at relatively low finish rolling temperature because of the ferrite grains refined. Fast cooling after low temperature rolling results in the ferrite grains refined and the formation of martensite islands. As a result, the product of ultimate tensile strength and total elongation (Rm×A50) of specimen 4 with fast cooling after low temperature rolling reaches the maximum value (18096MPa%).

Materials Characterization I

Abstract: The effect of heat input on microstructural zones, hardness and fracture of T-joints in EN S235JR carbon steel was evaluated using the Vickers hardness, SEM, and fractography on impact fractured specimens. The gas metal arc welding (GMAW) process with pulsed metal arc transfer and different welding speeds was performed by an industrial robot using a teaching pendant. Microstructural observations revealed differences in the size and quantity of phases exhibited in the solidified weld bead and recrystallized heat affected zone (HAZ) as well as a refinement of ferrite with different morphologies when a greater heat input was generated. The hardness results indicated greater hardening with greater heat input for the weld bead than the HAZ, which was associated with fine secondary Widmastätten ferrite sideplates growing from columnar grains separated by a larger amount of fine acicular ferrite. At a speed of 35 cm/min, the greater heat input produced a greater increase in volume fraction and width of HAZ with complex microstructures formed by fine-grained ferrite and acicular ferrite. The weld bead reached a greater hardening and volume fraction compared to the HAZ linked to fine acicular ferrite. The hardening of weld bead was confirmed by fractography that showed the presence of a small microvoid morphology I. Guzman-Flores • J.J. Gasca-Dominguez • J. del Prado • L. Rios-Vargas Manufacturera de cigueñales de México (MACIMEX), Centro de Investigación Innovación y Desarrollo Avanzado, Km. 38.5 Carretera la Marquesa, Tenango del Valle, Estado de México 52300, México e-mail: Isidro.Guzman@macimex.com; JuanJose.Gasca@macimex.com; Joaquin.DelPrado@macimex.com; Leopoldo.Rios@macimex.com B. Vargas-Arista (*) División de Estudios de Posgrado e Investigación, Instituto Tecnológico de Tlalnepantla, Av. Instituto Tecnológico s/n, Col. La Comunidad, Tlalnepantla de Baz, Estado de México 54070, México e-mail: benjaminvar@yahoo.com.mx E. Garfias-Garcia División de CBI, Departamento de Materiales, Área de Ingeniería de Materiales, UAM –Azcapotzalco Av. San Pablo No. 180, Col. Reynosa Tamaulipas, Azcapotzalco 02200, México e-mail: D.F.elgg@correo.azc.uam.mx

High Power Density Electrical Machines for Electric Vehicles—Comprehensive Review Based on Material Technology

Abstract: The growth of electric and hybrid electric vehicles has drawn more attention toward the development of high power density electrical machines. The materials used in the fabrication of electrical machines play a crucial role in enhancing their power density. In this paper, the significance of advanced magnetic materials for lamination, nano-material based conducting materials, and high energy product permanent magnets (PMs) is discussed in detail. Finally, a case study has been presented with a 5 kW PM synchronous machine in order to understand the advantages of the discussed materials.

Monitoring strain gradients in adhesive composite joints by embedding fibre Bragg grating sensors

Abstract: Keywords: Fiber Bragg grating ; optical fiber sensor ; composite joints Reference EPFL-CONF-183849 Record created on 2013-02-18, modified on 2016-08-09

Overview of anisotropic filtering methods based on partial differential equations for electronic speckle pattern interferometry.

Abstract: In this paper, we first present the general description for partial differential equations (PDEs) based image processing methods, including the basic idea, the main advantages and disadvantages, a few representative PDE models, and the derivation of PDE models. Then we review our contributions on PDE-based anisotropic filtering methods for electronic speckle pattern interferometry, including the second-order, fourth-order, and coupled nonoriented PDE filtering models and the second-order and coupled nonlinear oriented PDE filtering models. We have summarized the features of each model.

Replacement of silicon by aluminum with the aid of vanadium for galvanized TRIP steel

Abstract: Silicon existence in conventional low carbon TRIP steel is essential for inhibiting cementite precipitation, despite that it tends to obstruct the hot-dip galvanizing process. Aluminum is considered the mostly preferable substituent of silicon for such purpose. However, it has a counter effect on the strength/ductility balance of TRIP steel as a result of ferrite grain growth. Thereby, this study aimed to completely replace silicon by aluminum in the presence of vanadium in order to enhance the coatability of such grade of steel. Microstructure of the studied steel was examined by using optical microscope and FE-SEM. XRD analysis and tent-etching technique were performed to study the fractions and morphology of the retained austenite. Moreover, the influence of the selected parameters on the mechanical properties were investigated. Showcased results promoted the significant potential of aluminum and vanadium as a substituent to the conventional silicon-based TRIP steel. This substitution has a great influence on promoting the retained austenite stability and hence the mechanical performance of TRIP steel.